Vegetation and vegetational history of Northern Latin America - Graham 1973 by JPZ.

VEGETATION-AND VEG-ETATIONAL HISTORY OF NORTH ERN LATIN AMERICA PAPERS PRESENTED AS PART OF A SYM POSIUM, " VEGETATION AND VEGETAT IONAL HISTORY IN NORTH ERN LAT IN AMERICA", AT TH E AMERI CAN INSTIT UTE OF BIOLOGICAL SCIENCES MEETJN G,S. BLOOMINGTON, IN D. (U.S.A.), 1970

edited by

ALAN GRAHAM Departmelll of Biological Sciences, Ken/ State University, Kent, Oflio (U.S .A.)

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ELSEVIER SCIENTIFIC PUBLISHING COMPANY Amsterdam - London- New York

. 1973

Contents Preface . . . . . . . . . . . . . . . . . .

Chapter 1. The Vegetation of the Antilles RICHARD A. HOWARD Summary . . . . . . . . l ntroduct iOJl . . . . . . . Vegetation types in the Antilles Coastal formations . Lowland formations Montane forma tions Qrigins of the existing vegetation of the Antilles Relationships and distribution of the Antillean vegetation Disjunct distribution patterns in the Antilles . . . . . Distribut ion patterns wit hin the islands . . Long-distance 1elationships and disjunct distribution patterns Conclusions References . .

5 8 12 16 17

29 31 34 37 37

Chapter 2. A-Paleoclimatic Interpretat ion of the Eocene Floras of Southeastern

North America DAVID

D ILCHER

Summary . . . . . Introduction . . . Individual components of the fl ora Identification to modern taxa Evolution of the fossil taxa . Relation of range and ecological tolerance. Community structure . . . . . . . . . . . . Stability through time . . . . . . . . . Separation into equivalent modern communities Foliar physiognomy . . . . Leaf-margin analysis . . . . . . . . Leaf-size analysis . . . . . . . . . Interpretation of foliar physiognomy . Application to this nora Additional evidence Wood . . . . . . . Pollen . . . . . . . Paleoclimatic interpretations References . .

40 41 4t 42

43 44 44 45

46 48

50 53 54 55 55 55 56 57

Chapter 3. G eographical Relationships ofthe Flora of Mexican Dry Regions J. RZEDOWSKI Suillmary . Introduction

61 61

f X

CONTENTS

CONT ENTS

Relationships between diOcrent arid zones of Mexico Relationships with other arid zones of the world Relationships with zones of non-a rid climate . Conclusions References . . . . . . . . . . . : . â&#x20AC;˘ .

63 1;6'

70 71

Clrapter 4. Ecology of the Vegeta tion of Veracruz ARTURO G6MEZ-POMI'A

Summary . . . . Introduction . . . Physical condi lions Topography Climate Soils . Vegetation . . Forests Selvas . High sclvas . Low selvas . Grasslands . Arid or semi-arid vegetation Secondary vegetation References . . . . . . . . . . .

73 73 73 73 75 85

89 94 105 106 118

128 135

145 147

Chapter 5. The Phytogeography and Vegetation ofChiapas (Mexico)

149

149 150 154

155 155 158 161 163 164

Chapter 6. The Vegetation of Panama: a Review D UNCAN M. PORTER

Summary . Introduction Climate Soils Man Vegetation .

Vegetation maps . . . Koppen macroclima tes Holdridge Life Zones Human innucnccs . . . Darien forest types . _ . A summary of plant comnumiti<.,-s Incipient Forest . . . _ Early Secondary Forest Late Secondary Forest Liltoral Forest . . . . Thorn Forest _ . . . . Deciduous Seasonal Forest . Savanna .. . . . . _ . S<tltwatcr Swamp Forest . Saltwater Riparian Forest. Brackish Swamp Forest _ llrackish Riparian Forest Freshwater Marsh . . . Freshwater Swamp Forest Frcshw<tter Riparian Forest . Monsoon Forest . . . . Evergreen Seasonal Forest Premontane Rain Forest Cloud Forest Elfin Forest Acknowledgements ~ References . . . .

17 1

171 172 173 174 175

175 177 179

182 183 184 185 187 187 187

189 189 190 192

193 197

197 198 199 199 200

Chapter 7. Phytogeographic History of the Isthmus of Panama during the Past

DENNIS E. B REEDLOVE

Summary . . . . . . . Introduction . . . . . . Phytogeography of Chiapas . Vegetational formations ofChiapas Description of the formations . Optimum forma tions. . . . Seasonal format ions . . . . Wet-land forest formations . Treeless formations References . . . . . . . . . . .

167 167 169 170

170 171

12,000 Years (A History of Vegetation, Clima te, and Sea-level Change) ALEXANDRA S. B ARTLETT AN D ELSO S. BARGHOORN Summary . . . . . . . . . . Introduction . . . . . . . . . Northern South America . Southern Central America Panama . . . . . . . Geological history of Panama .. Pre-Quaternary history . . Late Quaternary and Recent history Physiography' and climate of Panama . Climate of the Canal Zone The present vegetation of Panama Preparation ofsamples . . . . Preparation techniques . Preservation of samples The pollen diagrams . . . . . Theoretical considerations The Gatun Basin diagrams The modern pollen rain . Climatic change in Panama . . . Identification and nomenclature of the fossil pollen .

203 204 .-

204

206 207 208

208 209

211 211

212 216 219

219 2 19 2 19

222 225 228

229

XII

CONTENTS

Nomenclature . . . . . . Vegetation 35,500 B. I'. Vegeta tion 11 ,300-9,600 B.P. Vegetatio n 9,600-7,300 ·1l.P.. Vegetation 7,300-4,200 B. P.. Vegetation 4,200 B.P. to the present Annotated list of species identified as po llen in Panama sediments . Monocotyledonac Dicotyledonae . . . . Other groups . . . . . Sea-level change- the literature Introduction . . . . . Early work Problems in interpreta tion of former sea leve l Sea levcl 35,000-18,000 D.P. . . . . . . . Climatic evidence from continental deposits . Evidence from oceanic cores Sea Jevel24,000-18,000 D.P. . . Sea leveJ· JB,000-10,000 D.P.. . Sea leveiiO,OOO B.P. to present Eustatic sea-level change in Panama . Introduction . . . . . . . . Mangrove pollen as a sea-level indicator. Sea-level data from the Gatun Basin Sea level 35,500 B. P. . . . . . . . .- . Sea level from4,200 B.P. to present . Acknowledgem ents References . . . . . . . . . . . . . .

CONTENTS

23 1 233 235 "239 241 245 249 249 255 268 268 268 269 269 27 1 274

I l J

ALAN GRAHAM

301 301 303 303 308 310 312

Chapter 9. Literature on Vegetationa l History in Latin America ALAN GRAH AM

Summary . . . . Introduction . . . General bibliographic references . Biogeography and his torical geology . Paleobotany of Mexico . . . . . . .

324 325 328 358

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36 1

277 277

Chapter 8. History of the Arborescent Temperate Element in the Northern L atin American Biota

Summary . . . . . . . . . . . . . . .......... . Introduction . . . . . . . . . . . . . . . . . . Origin of the eastern United S ta tes-eastern Mexican floristic relatio nship. Earlier studies. . . . . . . . . . . . . . . . . . . . . . . New data from the Miocene Pa rajc Solo Formation, Veracruz, Mexico Progressive southward introduction of the arborescent temperate element into the Latin American biota. Refere nces . . . . . . . . . . . . . . . . • .

Pa1cobolany of Cenlral America . Palcobolany of I he Antilles . . . Paleobolany of South America . Selected references o n I he pollen morphology of predominantly neotropica1 taxa .

276 276 282 282 283 290 29 1 293 293 294

315 315 316 316 319

XIII

Clwp/er I

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The Vegetation of the Antilles

RICHARD A . HOWARD Arnold Arboretum, Jamaica Plain, Ma.<s. (U.S.A.)

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Summary The Caribbean islands form an archipelago of over I ,000 islands of considerable range in size, alt it ude, soil types and environmental niches. l'he larger islands oft he Greater Anti lles have the largest number of species a nd the grea test endemism numerically. Especially on Cuba and Hispaniola there are geographic areas of high speciation and these arc largely_areas of mesophytic to xerophytic environments. Although there are many small endemic gen~ra restricted t o one or a few islands, only two genera with twenty s pecies o r more appear to be li mited to the Antilles. One fa mily, Picrodendraceae, is restricted to the Greater Antilles. Patterns of d isjunct distribution are ab undan t and involve the Greater Antilles a nd the lesser Antilles; islands of the Greater Antilles and Central America, and the Greater A nti lles and South America. Examples are ci ted of the relationships of the Antillean flora to Africa and to Asia.

Introduction The islands of the West Indies, the Ant illes, form an archipelago, that is, a series of small land masses scattered in a sheet o f water. In the southern part of t heir distribu tion their orientation north and south separates the Caribbean Sea from the Atlantic Ocean. Exposed land surfaces cover a distance of I ,700 miles from Barbados on the east to t he western tip of Cuba, while the distance from Grenada in the Lesser Antilles to the northern tip of the Bahamas is I ,200 miles. Nearly 1,000 named and vegetated islands comprise the Antilles, ra nging in size from Cuba, with 44,220 sq. miles and a vascula r flora of over 6,000 species, to i:;lets or small rocks of a few square yards and a flora o f a dozen species. Although isolated from each other at sea level, the islands are related below the surface in three prominent sweeping curves revealed· as sea mounts by under-sea exploratio n. The Bahama Islands appear as a continuation of the North American coastal shelf. The deepest point in the Atlantic Ocean, 27,500 ft., occurs in the Puerto Rico trench between the southern exten sion of the Bahama Bank and the Antillean arc. Lines of sea mounts extend south and west from the Greater Antilles, but present information is only speculative as to ·whether these existed in the past as continuous

, 2

R. A. HOWARD

T H E VEGETATION OF THE ANTILLES

land bridges for biological migrations. However, Grenada on the south is sepa rated from the South America n coastal shelf by a narrowj rench and by a sea-level distance of eighty miles. Western Cuba and the Yucatan peninsula are but I J 5 miles apart at sea level. The diversity of the Ant illes is seen in such factors as the altit ude of the islands, the temperature range, the soil types and the units of vegetation on each island. Hispaniola has the grea test rai1ge in altitude where the Enriquillo Basin is 100 ft. below sea level and the highest mountain is reported to be 9,700 ft. (Fig. I). Volcanic peaks in the Lesser Antilles range from 3,000 ft. to approximately 5,000 ft. The major part of

9,'100 8 ,300

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1'vlean average 1empemture

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Mean 11//IIIWI precipitation

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June

December

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II :29

13:42

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Havana Nassau

25. 1 25.6 26. 1 24.9 25. 1

1609 1275 1979 11 57 118 1

Grenada (560 m) Martinique (725 m) Guadeloupe (510 m) Puerto Rico ( 101 5 m) .

24.0 23.2 21.3 18.6

4 165 5.273 2630 4533

Dominica

J,600

TJ\ ULE J CLIMATE WITH IN l'II E \VfST INDIES

receives that quantity Gf water, the vegetation of the area suffers a water deficiency which is shown in progressive stages of wilting, leaf fall and eventual death of the plant. Many areas of the Antilles receive less than 40 inches of annual rainfali. Jn fact, there was no rain reco rded fo r a period of 3 years by personnel of the Sea Board Oil Company workin g in the Enriquillo Valley in Hispaniola in the 1950's. Rainfall exceeding 200 inches annual precipitation has been suggested for several areas, but documentation is in freq uent. Many areas of the Antilles show periods of 6 or 7 months of reduced rainfall occurring as two dry periods when part of the vegetation may lose its leaves and show mass flowering. In these areas irrigation is necessa ry for

J,lOO ;!)

3,200~

2,800 0

Fig. !. Altitudinal data on the islands of the Antilles. Diagonal lines indicate areas of less t han 1,000 ft . D otted areas exceed 3,000 ft. Highest mountains are indicated by appropriate numbers in feet.

the land surface within the archipelago is below 1,000 ft. in altitude. Although there are vegetational changes with altitude, there is no timber line within the Antilles and no high-altitude tundra or paramo. The average mean temperatures of the area, presented in Table I, are taken mostly from reports of government weather stations at elevations of less than 100m. Temperature range throughout the year is not great, nor is the daily variation in temperature. Day-length range is nearly two hours greater in Nassau in the north than it is in Trinidad just south of the area under consideration. With reference to the rates of evaporation within the area of the Antilles, the figures of 40 and 48 inches of rainfall have been cited as significant in determining the type and distribution of vegetation in the tropics. According to Beard (1949), the critical rainfall figure for the West Indies is 4 inches per month. Unless an area

~ SILICEOUS

J~11f:;l SALT~CYPS\n-1

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VOLCANIC-SOU!'RI&RE

ALUMINOUS-LATERITIC

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Fig.2. T he distribution of special soil types within the Antilles.

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R. A. HOWARD

T H E VEGETATION OF TH E ANTI L LES

commercial production of sugar cane or bananas. Other areas show no months of rain fall deficiency of less than4 inches, as exemplified by a lowland weather station on Dom inica or mountain stations in Puerto Rico and Martinique. The Antilles show a vari::ty of soil types which offer ecological niches or interesting areas for the plant collector to examine. The vegetat ion on the various soil types is often distinctive in composition or habit and is frequently high in endemic species. The accompanying map, Fig.2, indicates the location of siliceous savannas in western Cuba and on the north coast of Puerto Rico. The central area of Cuba has an interrupted serpent ine savanna dominated in various areas by shrubs or by palms. Areas or gypsum and salt concentration s, often in bands from an exposed syncl inous geological structure, occur in Hispaniola. A belt of alu minous lateritic soil extends through most of the island of Jamaica and occurs also in the southern peninsula of Hispan iola. Areas of volcanic activity occur in the Lesser Anti lles, with eruptive activity in this century on Martinique and St. Vincent. Fumeroles, sulfur vents and boili ng la kes with varying degrees of activity are encountered from Grenada to Montserrat. Outcrops of I imesto ne as sedimenta~y rock or elevated coral reefs are abundant and intrusive areas of igneous rock could be added to the_ chart as additional specialized habitats.

Montane formations lower montane rain forest montane rain forest or cloud forest montane thicket high mountai·n forest elfin woodland or mossy fo rest paramo tundra

Optimum/ormation rain forest Seasonal formations evergreen seasonal forest semi-evergreen seasonal forest deciduous seasonal fores t thorn woodland cactus scrub

deSert

Dry evergreen formations dry rain forest dry evergreen forest dry evergreen woodland and littoral woodland dry evergreen thicket and littoral thicket evergreen bushland and littoral hedge rock pavement vegetation

Sll'amp formations swamp forest and mangrove forest swamp wood Ia nd. swamp thicket herbaceous swamp

Stehle (1945, 1946) considered only the forest types of vegetation in the Lesser Antilles and presented a classification dependent on altitudi nal distribution, ra infall and soil type as the follo wing system . MangrOI'I: marine riparian

Mesophytic calcareous volcanic

Xerophytic · spiny deciduous sandy calcareous volcanic

Hygi'Ophytic marshy humid

Vegetation types in the Antilles

The history of botanical interest in the Antilles is a long one, but it has been devoted primarily to the studies of individual islands from the time of Columbus to the na~onalistic studies of island groups of more recent years. No comprehensive flo ra exists for the Antilles nor is one in preparation. As a result various systems of classification have been proposed for the vegetation of the Antilles or for individ ual islands. An extensive bibliography is given by Stehle (1945, 1946), although the proposals most wi_dely quoted are those of Beard (1944, 1949, 1955). Beard ha s proposed, with Clementsian terminology, a three-part vegetation classifica tion based on: (a) a floristic grouping-the climax association; (b) a physiognomic grouping-the forma tion; and (c) a habitat grouping- the formation-series. The following twenty-eight categories he recognizes are applied to all of tropical America, but not all are represented in the Antillean archipelago.

Seasonul-su·amp formations seasonal-swamp forest seasonal-swamp woodland seasonal-swamp thicket savanna

1 )

•

Altitudinal alluvial volcanic culminating

In order to consider the composition, distri bution and relationships of the Antillean vegetation it is· desi rable to discuss and il lustrate some of the vegetational types. The following modified classification will be followed wh ich utilizes the geograph ic location as well as the ecological fac tors of the area . Coaslal formations beach strand rock pavement mangrove Lowlandformations thorn scrub savanna marsh or swamp alluvium

Montana formations wet or dry forests on li mestone montane sclerophyll palm brakes tree fern communities pine forests cloud for~ts volcanic and soufriere communities crater lakes elfin thickets

Coastal formations

The beaches of the Caribbean area are attractions for the tourist and the botanist alike (Plate I, 1). Undisturbed beach areas are increasingly difficult to find. Sandy beaches, however, are oflimi ted extent on the islands of the Antilles when compared with the rocky or coralline coastal areas. Beaches may be composed of white sand of

R. A. HOWARD PLATE I

I. 2. 3. 4. 5. 6.

Sandy beach and strand vegetation o n Beata Is land, Hist>aniola. Alluvial bay with Avicennia, Balis and Sesuvium, Puerto Rico. Dry-thorn scrub vegetation, Jamaica. Savanna area with Prosopis, Antigua. A limestone cliff or mogote with thorn scrub vegetation, Jamaica. Enriquillo Basin, Hispaniola. Lake Enriquillo with the surface below sea level is in the upper right hand corner . Edges of the syncline are seen with alternating zones of gypsum a nd salt rock outcrops. Thorn scru b vegetation includes areas of pure stands of cacti.

T HE VEGETATION OF T H E ANTILLES

coralline o rigin or black sand of vo lca nic origin . Some islands rnay have on ly one kind of sand beach, while others have li mited amounts of each kind. A spit o n the southern end· o f Gre nada is black sand on one coast and whi te sand on the other. Beach p lants mos t commonly encountered are Canal'a(ia (Legum inosae), Cenclrrus, Distichifis (Gramincae), Euphorbia (E uphorbiaccac), ipomoea (Convolvulaceae), Ses111·ium (Aizoaccac) and Uniofa (Gramincac). Both t he _genera and the species involved arc o f wide geographic distribut io n, and no endemic taxa occur in this zone (Sauer, 1967). Inland from the.coastal beach, dunes may be bu ilt up consisting solely of sand or may be of sand d eposi ted on a rocky substratum (Plate 1, 1). T he sea grape, Coccoloba ut•ifera, is the classic componeni of such strand areas, although t his species is not as universally d istributed as most textbooks claim. Also present in the strand vegetation are Bontia dap/moides (Myoporaceae), Caesa/piuia or Guilandina spp. (Legumi nosae), Clrrysobafanus icaco (Chrysobalanaceae), Erit/raflisfruticosa (Rubiaceae), Hippomane manciuefla (Euphorbiaceae), Met opium toxiferum (Anacardiaceae), Scaet•ofa plumieri (Goodei1iaceac), Suriaua maritima (Su rianaceae or Simarou baceae), Toumejortia gnaplzafodes (Bo raginaceae). These are mostly examples o f single species of wide distri bution. Nearly all present taxonom ic or morphologic problems regmding their classificat ion or relat i on~11i ps. The rock-pavement substratun1 for a recognizable type of vegetation rnay occur ~ coastally on uplifted coral reefs as benches; dominate entire islands of such origin as in the Bahamas; or occur in isolated outcrops in inla nd areas. Such benches and elevated reefs are usually of soft rock, porous and weathered into sink holes of various sizes. They may consist of·extremely hard rock. On the soft rock matrix the vegetation is commonly rooted ove1 a considerable a rea. Succulent herbaceous species of Sesut'ium (Aizoaceae), Portulaca (Portulacaceae), A chyranthes (Amaranthaceae) and Peetis (Composi tae) are abundant. Where s h rubs predominate, the genera Rachical/is, Ernodea (Rubiaceae), Lantana (Verbenaceae), Jacquinia (Theophrastaceae) and Strumpfia (Rubiaceac) may be well rep resented by ind ivid uals of one species or several species. Spectacular coastal benches occu r at the easte111 end of Cuba aro und Punta Maisi, and a series of uplifted coastal benches are found on the so uthern coast of Hispaniola extendin g inland to considerable altitude. Globular growth fo r ms of cacti (Mefocactus) are consp icuous while spiny shrub .vegetation may consist of a large number of endemic genera or unusual genera as Phylostylon (Ulmaceae), tree forms of Cnidoscolus and Victorino (Euphorbiaceae) and clad ophyllo us species of Phyllanthus (Euphorbiaceae). More common s hru bs include Catesbaea (Rubiaceae), Co/ubrina (Rhamnaceae), Cordia (Boraginaceae), Dodonaea (Sapindaceae) Eugenia (Myrtaceae) Randia (Rubiaceae), Reynosia (Rhamnaceae) and Tabebuia(Bignoniaceae). The rock pavement areas may consis t of a very hard type oflimestone rock which erodes into sharp ed ges and which has a metallic ring when struck or when pieces are moved about (Howard and Briggs, 1953). The area has such a characteristic form that the rock is commonly known as d ogtooth limestone. Erosion may form sink holes of

R. A. HOWARD

considerable depth and the plants commonly have a deep tap root. Here one finds such genera as Comocladia (Anacardiaceac), Cynmantiles (Euphorbiaecac), Cuef/arda (Rubiaceac) and Swietenia (Me\iaceae). The mangrove vegetation type found in limited coastal atcas or in extensive swamp for mat ions has been subdivided by some workers into fresh-water or riparian and marine units. Four kinds of mangrove, as single species of Rhizopilora (Rhizophoracea~), Lagwrcu/aria and Conocarpus (Combretaceac) and A t•icemria (Verbenaceae) occur in the Antilles. Rhizopilora is the most abundant of the four occurring in pu re stands on the ocean side, but on the inland margin may be associated with such genera as Caesafpinia (Leguminosae), Dafbergia and Piscidia (Leguminosae), Ximeni; (Oiacaceae) and Acrosticllllm (Pte1 idaceac) as well as the other mangroves. The riparian mangrove formation has been characterized by Pterocarpus (Leguminosae), but this is at best of a limited occurrence. Hibiscus (Malvaceae) and Mac!taerium (Drepanocarpus) of the Leguminosae may also form pure stands or part of a mixture.

Lowland format ions A group of lowland formations may be recognized which can extend to or from the coastal areas. The most common and extecsive of these is a thorn scrub format ion in which the sharp-pointed or recurved hooks may be modified stems, stipules, leaves, inftorescent axes or emergences. Although this unit has been subdivided by Beard ( 1944, 1949, I955) as seasonal-formations and to a Jesser extent by Stehle (I 945, 1946) as xerophytic types, four units are of interest. The most common of the lowland formations is the thorn scrub, considered by many botanists to be the most diagnostic formation in the West Indies since it dominates areas of low rainfall and is most difficult to penetrate and most easy to remember (Plate T, 3). Abundant are Leguminosae as Acacia, Brya, Calliandra, Haematoxylon, Piscidia, Pithecef/obium, Pictetia; Cactaceae as Cereus, and Opuntia and their segregates; Rubiaceae as Guel/arda, Psychotria and Rondeletia ; Euphorbiaceae as A eidolon, Croton, Jatropha and Phyflantlrus; as well as Tabebuia (Bignoniaceae), Bw·sera (Burseraceae) a nd Raut•o/jia and Tabernaemontana (Apocynaceae). Individual plants of this vegetation in coastal areas may be modified into grotesque windswept aberrant forms. In the Dominican Republic and Haiti, a thorn scrub occurs in areas below sea level in the Enriquillo Valley-Cui de Sac area giving way to succulent sea coast vegetation at the shores of the lake {Plate T, 6). It also occurs on alternating salt rock and gypsum outcrops on the slopes of the abutting mountain ranges. Endemism is apt to be high in such areas, and the plants seem to be characterized by small flowers which appear infrequently. Beard attributes the occurrence of savannas (grasslands with scattered shrub growth) in tropical America to alternating periods of water-logging due to poor drainage and to dessication producing conditions too severe for the growth of trees

T HE VEGETATION OF THE ANTILL ES

(Plater, 4). The savanna he classifies as one of a series of seasonal-swamp formations. Stehle docs not recognize a savanna formation , presumably because he considers primarily the vegetation types of the islands of Guadeloupe, Dominica and Martinique. Savannas are infreque nt in the Lesser Antilles and the Grand Savanna of Dominica is the only good example of a Sporobo/us grassland with occasional shru bs of Haematoxylon (Lcgum inosae) and Byrsonima (M alpighiaceae). Savannas on siliceous soils are abui1dant on the Isle of Pines and Pinar del Rio provinces of Cuba and of limited occurrence in the area of Laguna Tortuguero on the north coast of Puerto Rico. These areas, however, may occasionally be so wet as to constitute classification as a swamp. A serpentine savanna occurs in central Cuba with the best examples in the Las Villas (Santa Clara) province (Plate II, 3). Shrubs may be more abundant and the composition of the vegetation more diversified with species of Byrsonima (Malpighiaceae), Jacaranda (Bignoniaceae), Rondeletia (Rubiaceae), and Erytlrroxylum (Erythroxylaceae) showing reduced leaf size. Unusual leaf forms also occur in genera of the Malpighiaceae as well as in species of Aristoloclria (Aristolochiaceae) and Passiflora (Passifloraceae). Other areas of serpentine soils may show a dominance of palms and the speciation of Copernicia in Cuba on serpentine soils is a classic example (Leon, 1946; Leon and Alain, 1951). ~ Areas of persistent moisture can be classi fied as swamp or marsh formations. The largest marsh or swamp in the West Indies is the Cienaga Zapata on the south coa>t of Cuba. An area of this swamp known as the Bahia de Cochinos or the Bay of Pigs has an historical political connotation. The saw grass C/adium (Cyperaceae) dom inates this area, yet ge nera of interesting distributional patterns also occur in the swamp. In open water are species of Va/lisneria (Hydrocharitaceae), Nymplraea and Nuplwr (Nymphaeaceae) and Po/ygonum (Polygonaceae) with northern rather than tropical affinities. In drier areas are found Solidago (Compositae), Cerardia (Scrophulariaceae) and Vicia (Legumi nosae), usually not regarded as tropical genera. Hammock vegetation in the Cienaga Zapata consists of Saba/, Coccothrinax and Acoelorrhaphe _(Palmae), but also Fraxinus (Oleaceae). Swamps are also found occupying large areas on the southern portion of the eastern end of Hispaniola in the vicinity of Higuey. Swamps at higher elevations may be the result of altered d rainage patterns such as the Mason River savanna in Jamaica (Proctor, 1970) and Sabana Nueva above San J uan de Ia Maguana in the Dominican Republic. Peculiar small hillside marshes or savannas occur in the Luquillo Mountains of eastern Puerto Rico. The occurrence of northern genera or those with montane South American affinities make such areas of particular interest. Ascyrum (Guttiferae), Drosera (Droseraceae), Lobelia (Campanulaceae), Potentifla (Rosaceae), Sisyrinclrium (lridaceae), Steffaria (Caryophyllaceae), Utricufaria (Lentibulariaceae), Viola (Violaceae) and Xyris (Xyridaceae) are often found in such swamps. The category of all uvial formations in the Antilles is a useful one and can include such areas as coastal embayments or river flood plains on many islands, the rich

R. A. HOWAR D PLATE I I

J. Mountains of the Cordillera Central of Hispaniola. A pine forest occurs on the ridges, with a broad-leafed vegetation in the valleys. 2. A pine forest in the Sierra de Moa, Cuba. Red lateritic soils support a flora rich in endemic species. 3. An area of serpentine soil with a savanna and shrub vegetation in the Las Villas province, Cuba. 4. A crater lake, the Grand Etang, in Grenada. A montane broad-leafed wet forest. The margin of the lake has a fl oating bog vegetation . 5. An abandoned c ultivated field in Ja maica has developed a shrub vegetation almost entirely of introduced weed species. 6. TI1e Botanic Garden of St. Vincent, the first botanic garden in the West Indies.

TH E VEGETATION OF TH E ANTILLES

I>LATE lll

1. An elfin summit forest in the Luquillo Mountains, Puerto Rico. Area of Prestoea 111ontana (Palmae)

in the upper left corner occurs on a landslide area. 2. Interior of elfin summit forest showing the density of the stems and the abundance of leafy liverworts and other epiphytes. 3. The Cockpit country of Jamaica. A limesto ne mass with steep-sided valleys. Dry limestone fores t type. 4. A mined out pit of bauxite soils, Jamaica. 5. Gage's Soufriere on Montserrat. An example of vegetation loss due to the heat and fumes of active fumeroles. 6. The slo pes of the Soufriere Mountain on Guadeloupe. Period ic emissions from summit fumeroles have killed the woody vegetation. Philodendron giganteum (Araceae) survives the fumes o r invades the affected area.

R . A. HOWARD

tobacco lands of Pinar del Rio in Cuba, portions or the Enriquillo Basin in Hispaniola and the bauxite areas of Hispaniola and Jamaica. The flat lands of Pin ar del Rio asso~iated with the mogotes of the Viiiales area support a vegetation with species or genera of disj unct distribution such as Befaria, Kalmia and Pieris or the Ericaccae, Laclmocau!on (Eriocaulaccae), Lechea (Cistaceae) and Quercus (Fagaceae). The endemic cycad Microcycas is also found in this area. The soils are generally rega rded as a derivative of the limestone mogotes. The occurrence of bauxitic ores in soils of Hispaniola and Jamaica have proven to be of economic significance to the respective cour.tl ;-.~ (?l:: te Ill, 4). The pockets of ba uxite soils occur in depressions in the base limestone rock of Late Eocene or Oligocene age and occur from elevations of 3,000-5,000 ft. The ore as mined is about 20 % ferruginous iron oxide, 50% alumina and less than 3 % silica. The origi n of the ore is still a matter of speculation fo r the base li mestone rock has less than 0. 1 % bauxite, hence a fa ir estimate of over 3,000 ft. oflimestone rock wou ld be required to be eroded and form the amount of bauxite occurring in some of the pits. A few endemic species of flowering plants are recognized on the bauxite soils in Hispaniola, but none has been discovered in Jamaica. The physiologica l effect of the alul]linum ions in the soil on the vegetation, however, has permitted a general classification of the species in the area of bauxite ~oil s as aluminum intolerant, aluminum tolerant and aluminum accumulating species (Howard and Proctor, 1957). Sand cays have developed in coastal areas on many of the Caribbean island s, enclosing bays of shallow water wh ich have been exploited as salt ponds historically as well as currently (Plate T, 2). Such alluvial areas, when unexploited or drying out, natu rally support a halophytic vegetation of succulent herbs as Achyranthes (Amaranthaceae), Atriplex (Chenopodiaceae), Heliotropium (Boraginaceae), Salicornia and Suaeda (Chenopod iaceae) and shrubs or trees as Annona (Annonaceae), Al'icennia (Verbenaceae), Batis (Bataceae), Capparis (Capparaceae), Dalbergia (Leguminosae), Pithecellobium (Leguminosae), and Thespesia (Malvaceae) .

TH E VEGETATION OF THE ANTILLES

fo rmation occurs in the Cockpit country of Jamaica where the erosion holes dominate and the limestone matrix is continuous. The palm genus Gaussia is fou nd on the mogotes of Cuba anti occurs elsewhere only in western Puerto Rico on similar limestone crags. Spathe!ia, a monocarpic member of the Ru taceac, is present on the mogotes of Cuba, in the Cockpit country of Jamaica and on the limestone islands of t he Bahamas. Several species of plants from Venezuela have been transferred recen tly to this genus, but the habi tat of the species is not descri bed. The best examples of stem gigantism in the Anti lles are Bombax emarginatum, found on the mogotes of Cuba. In general species of Andira (Legum inosae), Bucicla and Buchenavia (Combretaeeae), Dipholis (Sapotaceae), Oxandra (Annonaceae) , Sapium (E uphorbiaceae) and Zanthoxylum (Rutaceae) may predominate on the limestone outcrops. The dry limestone mountain forests of the Grenadines in the Lesser Antilles are composed pri marily of species of Bauhinia (Legum inosae) , Bourreria (Boragi naceae), Casearia (Flacourtiaceae), Coccoloba (Polygonaceae), Hymenaea and Lonchocarpus (Leguminosae), Spondias (Anacard iaceae) and Tabebuia (Bignon iaceae). A montane sclerophyll ype of vegetation, occurring in the Trinidad Mountains PLATE IV

Montane fo rmations The mountain vegetation of the Antilles can be subdivided as Beard has done, although a more simple approach is all that is required for descriptive purposes of this paper. Interesting limestone-based forests composed of primarily deciduous species with seasonal flowering characteristics are found on the mogote or haystack mountains of Cuba and Puerto Rico, the Cockpit country and the John Crow Mountains in Jamaica and on the Samana peninsula of Hispaniola (Plate III, 3; Plate I, 5). Endemis~ is apt to be high in these areas. Limestone-based forests of species of wider distribution are found on many islands of the Lesser Antilles. The origin of the mogotes as an erosional feature is clear. The mogotes a re usually steep-sided and composed of a porous structure and possess many erosion caverns. The mogotes are isolated and the valleys continuous in Cuba and Puerto Rico, but perhaps an earlier stage in their

J. The open aspect of a montane forest with trees of Dacryodes, S wartzia, PiJ/recellobium and Ta-

launza, St. Lucia. 2. C limbing plants of the Cyclanthaceae and Araceae dominate a montane forest on Gros Piton, St. Lucia.

R.A. HOWARD

T il E VEGETATION O F THE ANTILLES

and portio ns of the Sierra Macstra ranges of Cuba, predomi nates in Puerto Rico and o n most of the islands of the Lesser Antilles (Plate IV, I, 2) ..:rhe vegetation may occm in layers and Beard's classificatio n is based on the number of tiers of vegetation. The plant s comprising the vegetation are considered as evergreen, without coordinated leaf fall, and fl owering is mostly con tinuous rather than conspicuously seasonal. Genera arc numerous within this vegetati_on, and Stehle lists 175 genera with 385 species in the islands he considers. These are represented as 14% Burseraceae, 10% Lauraceae, 9% Elaeocarpaceae and 7% Myrtaceae. Asprey and Robbins ( I953) indicate the dominants in this forest in Jamaica to be species of Alcllomea (Euphorbiaeeae), Calopllyllum (Guttiferae), Ficus (Moraceae) and Psidium (Myrtaceae). ln the Lesser Antilles the dominant s are a few species of Dacryodes (Burseraceae), Sloanea (Eiaeocarpaceae), Sterculia (Sterculiaceac) and Licania (Chrysobalanaceac) (Hodge, 1954), altho ugh the genera Ormosia, Pitllecellobium and Swartzia (Leguminosae), Simarouba (Simaroubaceae) and Pouteria (Sapotaceae) are well-represented by individuals of single species. · Wi thin the broad-leafed montane sclerophyll vegetation the forest may be d ominated in places by palms. When these occur in conspicuous stands, as on the slopes of El Yunque in the Luquillo Mountains of eastern Puerto Rico, they indicate a n unstable soil area or rock slide zone. Beard has considered tl1e palm a successional development in areas affected by hurricanes, but Bannister ( 1970) disagrees as the resul t of her studies in Puerto Rico. My own as yet unpublished work on a plane crash cite in the Luquillo M ountains reveals palm seedlings as an early invader of open areas, with the fru its of Prestoea montana being distributed by birds and rodents. There is no ready explanation, though, fo r the pure stands of tree ferns, such as Cyatbea sp. often fo und in the Antilles. These are most common in Puerto Rico and occur frequently in the Leeward l slands of the Lesser Antilles. G enerally tree ferns of the Antilles are numerous, but scattered and many species occur only as subcanopy plants. The pine fo rests of the Antilles might be considered as a variation of the montane sclerophyll. The genus Pinus occurs in North America, but does not reach South America. fn the West Indies it is found only in Cuba and Hispaniola (Plate II, 1). I ts introd uction as a timber tree for afforestation has been successful on the other island s only when soil innoculants of mycorrhiza have been m ade. Pure stands of pine occur at low elevations in western Cuba and at higher elevations in the Oriente province of eastern C uba. The Cordillera Central of Hispaniola and the ranges of the southern peninsula possess pine forests on the ridges at higher to summit elevations with a broad-leafed sclerophyll fo rest in many areas in the river valleys. On the north coast of Cuba, near Moa, the pine forest occurs on lateritic iron-rich soils (Plate IJ, 2). Pine forests are good collecting areas for the botanist seeking unusual plant species, and the percentage of endemic species found in pine forests exceeds that oflowland forests. In Hispaniola alone the pine itself is parasitized by Arceutobium bicarinatum (Loranthaceae). This mistletoe has been considered an endemic species restricted to Hispaniola, but the genus is known from western North America as well as Asia. Recently

the same species has been recognized g rowing on Pinus oocarpa in Honduras in Cen tral America. A mo ng the shrubs found in the pine forests arc endemic species of Rubus (Rosaceae), Sah•ia (Labiatae) and Gesneria (Gcsneriaceae), but unusual genera in the Eupho rbiaceae and Mclastomataccae arc frequen t. The vegetatio n is reduced in stature and increases in density at the summi ts of the volcan ic peaks of the Antilles. Since many of these peaks are cloaked in clouds much of the time, the humidity is high and the woody vegetation is commonly laden with epiphytes (Plate Hl , I, 2). This type o f vegetation has been callccl·a mossy forest, an elfin fores t or a montane thicket. Detailed studies of such an area have been pu blished for o nly one such fo rmation (Howard, 1968, 1969) where it is ind icated that the grow th habits of the plants are unus ual in the abundance of a long-shoot- shortshoot and d ichotomous apical growth and of a sy!'n podial branching habit; the abundance of aerial o r advent itious ro ots; the low ferti lity o f the flowers and the red uced rate of metabolism and transpiration within the plants. The transition to lower-alt itude forest types may be gradual or relat ively abrupt. The principal genera in s uch areas may be Clus.ia (Guttiferae), Didymopanax and Oreopanax (Araliaceae), /nga (Leguminosae), Hibiscus (Malvaceae), /lex (Aqui foliaceae), Freziera (Theaceae), Riclreria (Euphorbiaceae), Weinmannia (Cunoniaceae), Tabebuia (Bignoniaceae), Ocotea ( Lauraceae), Psychotria (Rubiaceae) and Charianthus (Melastomataceae). The species p resent are widespread in their distribution in comparable environments and endemics are few. In the Lesser Anti lles volcanic activity has occurred in recent times, and there are currently active fumeroles ( Howard, 1962; Plate IIJ, 5). Regrowth of the vegetation is slow following cataclysmic volcanic activity, and the stages in this development can be found on peaks of adjacent island s. Species of Lobelia (Campanulaceae), Clrariant!rus and Tibouchina (Melastomataceae), Pitcairnea (Bromeliaceae), Cladium (Cyperaceae) and Freziera (Theaceae) appear to be the early invaders. Such fo rmations of scattered or low-stature plants are not comparable to tundra or paramos vegetation as has been suggested. The destruction and loss of vegetation in the lee o f active fumeroles can be observed on many islands. Species of the Araceae, Philodendron and Anthurium, Lycopodium ( Lycopodiaceae) and Pteridium (Dennstaediaceae) are the most resistent to the sulfur fumes or the first to invade a quiescent a rea (Plate HI, 6). A crater lake of about 17 acres and of considerable dept h is found on St. Vincent's Soufriere Mountain. Shallow crater la kes, some ephemeral, are on islands from Grenada to St. Kitts. Neither crater lakes nor fumeroles are found in the Greater Antilles. Eleocharis and Rhynchospora (Cyperaceae), and Nepsera (Melastomataceae) are the principal invading genera of the shallow margins of crater lakes with Montrichardia (Araceae), Miconia, Psychotria as the early invading shrubby genera. The marginal vegetation of the crater lakes often exists as a quaking bog (Plate II, 4). These then are some of the ecological niches on the islands of the West Indies in which plants exist. The total flora of the Antilles is conservatively estimated to be 8,000 species of flowering plants. Unhappily, the vegetation has been studied by many

R . A. HOWARD

THE VEGETATION OF THE ANTILLES

taxon omist s commo nly regarded a s "splitlers", eit her on the basis of their own j udgement of what is an individual taxo n or in the fact that their research is based on the flow of a single island wh ich t hey isola te from the adjacent island s or other areas in their limited considera tio ns. The monograph ic approac h at the generic or fa milial level to the vegetation of northern Latin America, including the Antilles, is needed. P robably not more than I0 % of the genera found in the area a rc represented by monogra phs published in the last fifty years. Thus there is an inherent difficulty of a weak laxo nomic base in mak ing broad sta tements or drawing conclusions on the distributio n of laxa within I he Anti lles . Nevertheless, this is the objective of this paper.

ment is necessa ry in considering the nat ive clements of the Antilles-tn a-discussion of the geographic ranges o f distri bution. In t he total flora of the Anti lles seven f;1mil ies of flowerin g plants predom inate in the number of genera, and there is onl y a slightly difTcrent composition when one considers the number or species as ind icated in Ihe followi ng ta ble. LARGE FAMILIES OF Tllf! WEST INDIAN FLORA

in order of the number of genera

iu order of the mt•nber of species

Composittic Gramincac Lcguminosac Rubiaccac Orchidaccac "Euphorbiaccac Mclastomataccac

O rigins of the existing vcgctalion of the Antilles T he total fl ora of the West Indies involves a sizeable com plemen t of weeds and extraterritorial cultivated plants, often now well-establ ished, which should be excluded from geographic considerations. Pre-Columbian movements of people in the Antillean area are known th rough many p teroglyphs and through a study of artifacts of kitchen middens ( Kirby, 1971). Neither of these sources of evidence of fo rmer occupation, however, yield much, i!' a ny, co nvincing evidence of the plant materials used and therefore p robably introd uced from one area to another. However, the occurrence of certain plants in t he Antilles may be the result of deliberate or accidental pre-Columbian introductio n. The post-Columbian introduction of cultivated plants now naturalized, often as weed s, is better documen ted (Plate Ir, 5). The records of Columbus' voyages indicale the Etfropean plants deliberately carried to be e~tablished as cultivated plants. The introduction of co mmercia l crops such as bananas, sugar cane and coffee can also be documented. The first botanical garden in the West Ind ies was established on St. Vincent in 1765 ( Plate 1[, 6) fo llowi ng the interest expressed by the colonial planters for additional plants of fo reign origin to improve the agricultural econ omy of this tro p ical area (Guildi ng; 1825; Howard , 1953). The voyages of Captain William Bligh for t he breadfruit bro ugh t plants from Europe to the Southern Hemisphere and from the South Pacific islands to fi rst St. Vincent and then Jamaica ( Howard, 1954). The French used the island of M a urit ius as a transplant point fo r East l ndian plants desti ned for the French co lonies and botanic gardens in the Antilles (Jacquin, 1797). An interest in establi shing plantations of rubber-producing species Jed to the introduction o f such plan ts from Central America, South America, Africa, Madagascar and the Pacific tropics (Howa rd and Powell, 1963). Many of the genera and species involved are established and not distinctive in the existing vegetation of the Antilles. The ackee (Biighia sapida) is associated now with the tra nsportation of slaves across the Atlantic Ocean from A frica and it is now well-established in Jamaica. If fruit trees and ornamental plants cou ld be transported, it is not difficult to believe that seed s of grasses and weedy plants could have been introduced just as easily. Thus some judge-

Gramincac Lcguminosac Rubiaccac Composilae Euphorbiaccac Orchidaccac Myrlaccac

Relationships and distribution of the Antillean vegetation The native genera of the AntiHes are mo stly small, appearing to average less than five species per genus. There are ten large genera with sixty or more species, and, as Table II indicates, Cuba a nd H ispaniola tend to have the larger number of species of all the islands. T he number of species in these genera ta pers o fT in the smaller islands a nd in the Lesser Antilles as a group a nd often does so in continental La tin America. Thete TABLE II DISTI\IIlUT ION Of WEST IND IAN G ENf!RA WITH MORE THAN

..!2 -~

.!;!

.§ g

"':-"

Croton Eugenia Miconia Panicum Paspalum Peperomia Phyl/anthus Pilea Psychotria Rondeletia

45 12t 46 71 61 45 65 65 67 60

66 62 64 47 39 60 24 100 37 26

16 45 24 28 26 38 22 45 51 28

13 25 17 31 24 21

II. Piper 12. Pleurotha/lis

30 38

33 27

14 27

I. 2. 3. 4. 5. 6. 7.

8. 9. I 0.

60 SPE CIES

'"'

.;;: ~ ·

.!,!

..!2

"'~

'"' "''"'

()

\:>

22-

16 17 3

51 28 21 23 50 20 20 17 6

13 20 36 39 39 71 II 17 49 5

20 18 65 38 32 176 10 25 52 9

32 63 69 39 57 69 18 26 28 25

10 7

27 18

96 55

371 138

96 68

'--l

R. A. HOWARD

T I-l E VEG ETATIO N OF T HE ANTILLES

are so me genera well-represented or developed in the Ant illes which have but a few s pecies occ urring ou tside or the Antilles. Other genera such as Ptj!l!r and Pleurothal/is a rc extre mely well-devel oped in Central or Sou th America and are less well-represented within the Anti llc~. T he genera which comprise the flora of the West Ind ies reveal ma ny patterns of distribution rang ing from patH rop ical genera to isla nd endem ics and those tbat show disjunct ranges (Fig.3) . These patterns will be cited with comments and documented with examples of genera selected to s how a particular geographic pattern. T he ex-

States; B = the Bahamas; C = Cuba; H = Hispaniola, including Haiti and the Dominica n Repu blic; J =" Jamaica; PR = P uerto R ico; LA = Lesser A ntilles, incl udi ng the Br itish Virgin Islands, the Leeward and Windward Islands south to and incl uding Grenada; CA = Cent ral America, including the tropical portions of Mexico and the Yucatan peninsu la; SA = South America, including T rin idad and Tobago as well as the Dutch islands or Aru ba , Bonaire and Curacao. No .attempt will be made in this paper to distinguish ranges from the Antilles into South America, although ranges to the cast and south from Venezuela occu r as do those west and sou th ft om Venezuela alo ng the A ndes. Both of these ranges may have ex ten~ i o ns into Brazi l or co untries fa r ther to the south. (!) Pan-Caribbean distribution (Table 111). A group of genera found on all o f the islands of the Greater Antilles, the majority of the islands of the Lesser Antilles, and represented in tropical Mexico and Central America and in northern South A merica. (2) A Western Cont inental unit (T able IV; Fig.4). A group of genera wh ich are well represented in Central America and may have a range extending into the Greater

Fig.3. The patterns of geographical distribution and relationship of genera of the West Indies.

amples given do not represent all of the possible examp les or an exhaustive survey of the West Indian genera. Species could also be selected to show th e same patterns. To the best of my ability I have avoided examples from families or of genera in which the existing taxonomic treatments are unsatisfactory. If a genus has been attributed to a geographic area with some question by some author and the record cannot be documented with an herbarium sp ecimen or the commen t of a monographer, I have ch osen to disregard the citation. The foll owing abbreviations will be used in the examples which follow. NA = North America; US = United States, although primarily the southeastern United

Fig.4. The major patterns of generic distribution within Latin America. Vertical lines indicate a Western Continental unit which extends eastward across the Greater Antilles usually terminating in the Virgin Islands (arrows), but with examples extending into Guadeloupe. Diagonal broken lines indicate the Southern Continental unit which extends nort hward in the Lesser Ant illes.

R. A. HOWA RD

Antilles as well as so uth and cast on the South America n continent. This unit is best shown as a lis t of those genera which arc missing in the Lesser Antilles. The extension of these genera across the Greater Antilles may involve Cuba, Hispaniola and Puerto Rico as a pathway and may include or exclude Jamaica. Usually the American and British Vi rgin Isla nds represent a geographic break or terminus of the generic range. Genera which do not appear to occur in Puerto Rico as an extension of the Western Continental ra!lgc or those that may continue into the Leeward 1slancls or Guadeloupe wi lt be listed separa tely as Table V and Table VI respectively. Examples of disjunct distribution between the islands oft he Greater Antilles and South America will be conside red as Tables XXVI - XX IX. Examples of genera wh ich occur in the Antilles and Central Ameri ca, but are wanting in South America form Table VII. (3) A Southern Continental uni t (Table Vllf; Fig.4). A group of genera which are well represented in South Americl) and appear to have a range extension northwa rd through the Lesser Antilles. A few genera may reach Puerto Rico, but these get~era have not been reported fro m Hispaniola, Cuba or Jamaica. (4) The Antillean unit. There are relati vely few genera which appear to be restricted solely to the islands of the Greater Antilles. The two genera _Wa!lenia (Myrsinaceae) and Calycogonium (Melastomataceae) (Table IX) with twenty or more species serve as examples of large genera in the West Indian floRI found only in the Grea ter Antilles. Table X lists genera better developed in the Antilles with a few species in South America, but which appear to be lacking in Central America. (5) Greater Antillean units. The size and complexity of the flora that has developed within the Greater Antilles can be shown best by the number of endemic genera now recognized ar'd their distributi on on one or more islands (Fig.5). Alain (1962) has estimated that Cuba has a flora of 5,800 species with approximately 50% of these endemic to that island. Included in the flora of Cuba are 41 endemic genera cited in Table X I. Although..figures of the total number of species for other islands are not read ily available in modern reliable statistics, estimates can be made of the approximate percentage of endemism and of the number of endemic genera. Hispaniola has specific endemism of about 33 %, and the flora includes 26 endemic genera (Table XII). Jamaica has four endemic genera (Table XIII) and approximately 20% of the flora is of endemic species. Puerto Rico (Table ~IV) has one endemic genus and about 4% of the species are endemic (Britton and Wilson, 1923/ 1924). In contrast, there are no endemic genera in the Bahama islands, but Britton and Millspaugh (1920) suggest that 13 % of the species are endemic. These species have not received study by monographers in recent years, and the figure is certainly high. There are no endemic genera in the Lesser Antilles and a realistic estimate of 12% represents the endemic species. In addition to the local, single island endemics, there are a number of genera restricted to one or more islands. Lists are given of examples of genera found only on Cuba and H ispaniola (Table XV), Cuba and Jamaica (Table XVI), Cuba and Puerto Rico (Table XVII), Cuba and the Bahamas (Table XVIII), Hispaniola and Jamaica

TH E VEGETATION OF THE ANT I LLES

Fig.5. Some distributional patterns within the G reate r Antilles. Estimates of specific endemism a rc given as a percentage, followed by the number o f e ndemic genera of Oowering plants. Generic distribut ion patterns whic h include more tha n one island arc indicated as follows: - . - . -Âˇ . Cuba, Jamaica, Hispanio la, Puerto Rico; ... .. Cuba, Hispaniola and J amaica, but excluding Puerto Rico; - - - - Cuba and Hispaniola, excluding J amaica and Puerto Rico; Cuba, Hispanio la and Puerto R ico, excluding Jamaica; --- - Hispaniola and Puerto Rico, excluding Cuba ~and Jamaica; - ... - ... Cuba and Jamaica. excl uding Hispaniola and Puerto Rico.

(Table XIX), Hispaniola and Puerto Rico (Table XX) and Hispaniola and the Bahamas (Table XX I). There are patterns of distribution of genera which involve th ree of the islands of the Greater Antilles or, in other words, in which a genus has not been reported-from one of the major islands. There are genera which are not present on Cuba, but do occur on Hispaniola, Jamaica and Puerto Rico (Table XX Il) and genera which are absent from Hispaniola, but occur on Cuba, Ja maica and Puerto Rico (Table XX I B). The listings are larger for genera which a ppear to be lacking on either Jamaica (Table XXIV) or Puerto Rico (Table XXV). TABLE Ill EXAMI'LES O F GENERA O F PAN-CARIUBEAN D IST RIBUTION

Amyris (Rutaceae) Anoda (Malvaceae) Apteria (Burmanniaceae) Ardisia (Myrsinaceae) Beilschmiedia (Lauraceae) B;1melia (Sapotaceae) Burmannia (Burmanniaceae) Cedrela (Meliaceae) Celtis (Ulmaceae) Chlorophora (Moraceae) Clidemia (Melastomatacea e)

HMella (Rosaceae) Homalium (Fiacourtiaceae) Jacquinia (Theophrastaceae ) Leiplwmos (Gentianaceae) Linociera (Oteaceae) Manellia (Rubiaceae) Morcgravia (Marcgraviaceae) Miconia (Melastomataceae) Myrica (Myricaceae) Ocoteo (Lauraceae) Ossaea (Melastomataceae)

T HE VEGETATI ON OF THE ANTILLES

R. A. HOWARD

TABLE V

TABL E Ill (conriuuctl)

- - -- --·--·------Co!J11mtcll (Gcsncria~cac) Collo.,rcgiu (Mclastomat<lccac) Comuria (Ycrbcna~cac) Cyrilla (Cyrillaccac) Daplmupsis (Thymcl:tcaccac) Eryrltroxylwn (Erythroxylaccac) Ewmcma (Rubiaccac) Grit.f}enriedia (Mclastomataccac) Guarea (Meliaccac) Gtutzwna (Eiacocarpaccac) Guellarda (Rubiaccac) Hemandia (HcrnallCiiaccac) Hillia (Rubiaccac) Hippocrarea (Hippocratcaccac)

EXAM I'll:._') OF G f. N I:I~A W II ICil DO NOT tti:ACI I PU_f-UTO IUCO AS AN E,\STEH. N I.:X'n~NSION OF A. Wt:STERN

Ourarca (Ochnaccac) Oxoudm (Annonaccac) Picramnia (Silmrubaccac) Pudocarpu.1· (Podocarpaccac) Rondeletia (Rubiaccac) SaMa (Labiatae) Sopium (Euphorbiaccac) Scltlegelia (13ignoniaccac) Scltoepfia (Oiacaccac) · Si11wrouba (Simaroubaccac) Strucltiwn (Compositac) Tiboucltina (Mclastomataccac) Tricltilia (Mcliaccac) WeiunWJmia (Cunoniaccac)

C'ONTIN I: NTI\L H AN(iJ:

MatlfJia (!cacinaccac) CA. SA Mascagnia (Malpighiaccac) CA, SA Neurolaena (Compositae) CA , SA Oocarpwr (Onagraccac) CA, SA Plryllosry/on (Ulmaceae) CA, SA Rammw/us (Ranunculaccac) CA, SA Samolus (Primulaccac) US, B, CA, SA Srexnaspemw (Phytolaccaccac) CA Tapura (Dichapctalaccac) CA, SA Va/lcsia (Apocynaccac) US, B, CA, SA Zuclania (F iacourtiaccac) B, CA

All•ttrttduo (Simaroubaccac) US, B, CA, SA Areuaria (Caryophyllaccac) US, CA, SA Budt!/eia (Log;•niaccac) CA , SA Esenbeckia (Rutaceac) CA, SA Eusroma (Gcntianaccac) CA, SA Forchlwmmeria (Capparaccac) CA, SA Gonya (Garryaccac) US, CA Kosrelerzkya (Malvaccac) US, CA, SA Laeria (FiacourtiacC<lC) CA, SA Liabum (Compositac) CA, SA Lwwnia (Fiacou rtiaccac) CA, SA

TABLE IV WESTERN CONTI NENTAL UNIT-'EXAM I'Lf.S OF GENERA MISSING FROM THE LESSI! R ANTILL ES

- - -- - - -- - - - · -·

lld.wmtltera (Mclastomataceae) GA, CA, SA Alcltomca (Euphorbiaccac) GA, CA, SA Augdnnia (Scrophulariaccac) GA, CA, SA Atriplex (Chcn opodiaccac) GA, CA, SA Bmnellia (Brunelliaceac) GA. CA, SA Buclmera (Scrophulariaccac) US, B, GA, CA, SA Callimrpa (Yerbcnaccac) US, GA, CA, SA Cleyera (Thcaceac) GA, CA Dct~drorJcmoll

( Loranthaccac) GA, CA, SA Det1drophrltora (Loranthaceac) GA. CA, SA Drosera (Droscraceae) NA, GA, CA, SA &·hires (Apocynaceae) US, GA, CA, SA Ehretia (Borag inaccae) GA, CA, Asia Esenbeckia (Rutaceae) C, H, J , CA, SA Eusloma (Gcntianaceae) US, B, C, H, J, C A Forchlwmmeria (Capparaceae) C, H, J, CA, SA Forsreronia (Apocynaccae) GA , CA, SA Gerardia (Scrophula riaceae) US, GA G01·rya (Garryaceae) C, H , J, CA, US Gyminda (Celastraceae) US, GA, CA He/icleres (Sterculiaceae) GA, CA, SA Hieronima (Euphorbiaceac) GA, CA, SA Hyperbaena (Me(lispermaccac) G A, CA, SA lsocarpha (Compositac) US, GA, CA, SA Jug/01rs (Juglandaceae) C, H, PR, CA, SA, US Laetia (Fiacourtiaceac) C, H, J, CA, SA Laplacea (Theaceae) GA, CA, SA Liabum (Compositae) C, H,J, CA, SA Licoria (Lauraceae) US, GA, CA, SA Lwrania (Fiacourtiaceae) C, H, J, CA, SA Lyonia (Ericaceae) GA, CA, US, Asia Machaonia (Rubiaceae) GA, CA, SA Macrocarpaea (Gentianaceae) GA, SA, CA

TABLE Vf

Magnolia ( Magnoliaccac) C, H, PR, CA, SA Mappia (lcacinaccac) GA, CA, SA Mai'sdcnia (Asclepiaclaccac) GA, CA, SA Mawyba (Sapindaccac) G A, CA, SA Meriania (Mclastomataccac) GA, CA, SA Nama (Hydro phyllaccacl US, GA, CA, SA Neea (Nyctaginaceac) GA, CA, SA Newolaena(Composi tac) C, H. J , CA, SA .Oocarpon (Onagraceac) C, H, J , CA, SA Ossaea (Melastomataccae) GA, CA, SA Oxyperaltan (Asclcpiadaceac) GA, CA, SA Phaeo.1plwerion (Commelinaceae) C, H , PR, CA,

EXMII'LES O F GENERA OF T i lE GREATER ANTI LLES W HI CII REACII THE LEEWARD (NORT"IIEH N) ISL ANDS OF HI E L ESSER ANTILLES

Borrichia (Compositac) US, B, GA, Guadeloupe Forcsriera (Oicaccac) US, B, GA, CA. Antigua Gltinia (Vcrbcnaccac) C , H, PR, CA. SA, Antigua Hybam/ms(Violaccac) C, H, PR, CA, SA, Guadeloupe Hype/arc (Sapindaceac) US, B, GA, Anguilla Metopium (Anacardiaceac) US, GA, Anguilla Mouriri (Mclastomataceae) GA. CA. SA. G uadcloupc NymtJiwides (Mcnyanthaccae) GA, CA, SA, Guadeloupe Rubus (Rosaceae) US, GA, CA, SA,St. Kitts Srrrmrpjia (R ubiaceac) US, GA, Guadeloupe

-Phyllosrylon (Ulmaceae) C, H, CA, SA Portlandia (Rubiaceac) GA, CA .Pseudo/media (Moraceae) GA, CA , SA Rachicallis (Rubiaceae) B, GA, CA ROirrmcrt/us (Ranunculaceae) C, H , J, CA, SA Ravenia (Rutaceae) GA, CA, SA Sag if/aria (Aiismataccae) US, GA, CA , SA Salicomia (Chenopodiaceae) B, GA, SA, CA Sa/mea (Compositae) GA, CA, SA Samolus (Primulaceae) C, H , J, CA, SA Sarcoslema (Asclepiadaceac) US, B, GA, CA, SA Schaefleria (Celastraceae) US, GA, CA, SA Scybalium (Balan ophoraceae) GA, SA Sregnosperma (Phytolaccaceae), C , H , J, CA Stel/aria (Caryophyllaceae) B, GA, CA, SA Solandra (Solanaceae) GA, CA, SA Thalia (Marantaceae) GA, CA, SA Valeriana (Yalerianaceac) NA, GA, CA, SA Ximenia (Oiacaceae) US, GA, CA, SA Zamia (Cycadaceae) GA, CA, SA

T ABLE Vfl

EXAMPLES OF WEST INDIAN GENERA WH ICH A P PEAR TO MISS SOUTH AMERICA

Bor.-iclria (Co mpositae) US, B, GA, LA Carpadiprera (Tiliaceae) C, H, LA, CA

Lyonia (Ericaceae) US, GA, CA Masrichodendron (Sapotaceae) US, GA, LA, CA

Dip/ro/is (Sapotaceac) US, GA, LA, CA

Phialam/rus(Rubiaceae) GA , LA, CA

Elrrelia (Boraginaccae) GA, CA Eritlral/is (Rubiaceac) GA, LA, CA

Samyda (Fiacourtiaceae) GA, LA, CA Stegnosperma (Phytolaccaccae) C, H, J , CA Terrazygia (Melastomataceae) GA , LA Tropidia (O rch idaceae) US, GA, LA, CA Ureclrites (Apocynaceae) GA, L A, CA

Ernodea(Rubiaceae) US, GA, LA Exot/rea (Sapindaceae) US, GA, LA, CA Gyminda (Celastraccae) US, GA, CA Krugiodendron (Rhamnaceae) US, GA, LA, CA

R. A. HOWARD

T HE VEGETATION OF THE ANTILLES

TAllLE VIII

TABLE X

SOUTIWRN CONTINENTAL l!NIT- EXMII'LES 0 1' v ENf.RA OCCUIHU I':G IN TilE LESSF.R ANTI LLES HUT Wll l{'ll DO NOT OCCUI{ IIEYOND I'UERHl RICO IN Ti lE v REATER ANTII.LI;5

I.XAMI'LI~S

ANTILI..I~AN

/Jomia (Myoporaccac) ll, GA, LA, SA Casasia (Rubiaccac) US. ll, C, H, J, LA, SA Cymlu>carpa (llurnmn niaccac) C, H, J, SA Gesneria (Gcsncrinccilc) GA, LA, SA HuriWIIWIIIIia (Ericaccac) GA, LA, SA Nepsera (Mclastoma taccac) GA. LA, SA Rhytidopltyllum (Gcsncriaccac) GA, LA Schradera (Rubiaccac) GA. LA, SA Tetrazn:ia (Mclastomataccac) GA, LA , SA

A11umoa (Euphorbiaccac) SA, Guade loupe, Dominica A11iba ( Lauraccac) LA, CA, SA, Puerto Rico Browallit1 (Solanaceae) LA, SA Ca/u/isiant/ms(Gcntiana=c) LA, SA

Cenlropogon (Campa.nulaL·cac) LA, CA, SA C/wme/ia (Rubiaccac) LA, CA, SA Cltrysuch/amys (Guttifcrac) LA, CA, SA Codonantlte (Gcsncriaccac) LA, SA, CA Coutonbea (Gcntianaccac) LA, SA, CA Dacryodcs (llurscraccac) LA, SA, CA, Puerto Rico Drymonia (Gcsncriaceae) LA, SA, CA Dussia (Lcg uminosac) LA, SA, CA Enicostema (Gcntianaccac) LA Gonolobus (Asclcpiadaccac) LA, SA, CA, Puerto Rico Isclmm·il'holl (Marantaccac) LA, SA, CA, Puerto Rico Licania (Chrysobalanaccac) LA , SA, CA Malanea (Rubiaceac) LA, SA Nauti/o caly.r (Gcsncriaccac) LA, SA, CA Nomntea (Marcgraviaccac) LA, SA, CA Petrea (Vcrbcnaceae) LA, SA, CA Pres1o11ia (Apocynaceac) LA, SA, CA Plerc/epis(Mclastomataccae) LA, SA, CA Riclteritl (Euphorbiaceae) LA, SA Rola11dm (Compositae) LA, SA, CA, Puerto Rico Ruyschia (Ma rcgraviaceae) LA, SA, CA Sipanma (Monimiaceae) LA, SA, CA Srylogyl/e (Myrsinaceac) LA, Puerto Rico To••omita (Guttifcrac) LA, SA, CA Willmackia (Bromcliaceae) LA, SA, CA, Puerto Rico

(ii::"\F.RJ\ W I IICJI ARI-: LAC KING IN CI:I'\'T!tAL AMERICA

TABLE XI G ENERA

Ancistrimt/w;- (Acanthaccac) Behaimia (Lcguminosac) !Jembi<'idium (Lcguminosac) Caribea (Nyctaginaccac) Cerlllopyxis (Rubiaccac) Cubat'I'OI<III (Euphorbiaccac) Dm·ytropi.~

(Acan thaccac)

Doerpfcldia (Rhamnaceac) Eosanthe (Rubiaccac) Espadaca (Solanaceae) Euc/wrium (Sapindaccac) Euleria (AnaCHrdiaceac) Goerzie//a (Amaranthaccae) Hamackia (Compositac) Hebe.~ti~tma (Lcguminosac)

Hen/eaphytu111 (Malpighiaccac) Heptwlllws (Compositac) Herpyza (Lcguminosac) Koe/meo/a (Compositae) Lescai//ea (Composilae)

~NDEM IC

TO CUll/\

Linude11dmn (Thymclaeaceae) Megalopanax (Araliaceae) Microcycm· (Cycadaccac) Nodoct/J}Jea (Rubiaccac) Pllidiasia (Acanthaccac) Plty//acamlms (Rubiaccac) Phyllomelia (Ru biaccac) Piuosia (Caryophyllaceac) Rlwdogerou (Compositac) Sapphoa (Acanthaccac) Sclllnidtollia (Rubiaccac) Slwfera (Compositae) Sieme11sia (Rubiaccac) Solonia (Myrsinaccac) Spirotemma (Bignoniaccae) Tetralix (Tiliaccac) Tetraperoue (Compositac) Web;-teria (Cypcraceae) Woehleria (Amaranthaceae) Zollalllhus (Gentianaceae) TABLEX!l GENERA ENDI: MI C TO HISPANIOLA

TABLE IX EXAM P LES OF ANTILLEAN GENERA MISSING IN CENTRAL AMERICA AND SOUTH AMERICA

Ca/ycogonium (Melastomataceae) Catesbaea (Rubiaceae) Hype/ate (Sapindaceae) Lasiantlws (Rubiaceae) Reynosia (Rhamnaceae) Strumpfia (Rubiaceae) Wa//enia (Myrsinaceac)

Arcoa (Legum inosae) Coe/olleurum (Solanaceae) Cryplorhiza (Myrtaceae) Ekmmtiocltaris (Melastomataceae) Fuertesia (Loasaceae) Haitia (Lylhraceae) Herodtia (Compositae) Hybosperma (Rhamnaceae) Leprogommt (Polygonaceae) Mallfe/dia (Compositae) Mommseuia (Melastomataceac) Neobuchio (Bombacaceac) Pedinopetalum (Umbelliferac)

Peue/opeia (Cucurbilaceae) Peratautbe (Rubiaceae) Piperomhera (Piperaceae) Poitaea (Leguminosae) Pterocissus (Vitaceae) Rhodopis (Leguminosae) Sarcopilea (Urticaceae) Se//eo/a (Caryophyllaceae) Stevensia (Ru biaceae) Ulbrichia (Malvaceae) Vegaea (Myrsinaceae) Wuuschmannia (Bignoniaceae) Zombia (Palmae)

R. A. HOWARD

T HE VEGETATION OF H IE ANTILLES

T AllLE XIII GENER A I' NI>IO MIC TO JAMA ICA

Dcndroeoasinia (Euphorbiaccac) Jamima (Asclcpiadacc:.c) Peltosligma (Rutaceac) Telrasiphon (Cclastraceac)

TABLE XIV

TA BLE XV I foXAMI'I.I'S OF GI'NiillA FOU ND IN C UBA AND JA MAI C'A, BUT W ill('! I AP P EAR TO llli MISSING IN IIISl'ANIOLA ANI) I'UI'IlTO RICO

Acro.\ytwmlw.l· (Rubiaceae) endemic Auerudemlrou (Rhamnaccac) B Bemardia (Euphorbiaccac) LA Cenlaurium (Gcntianaceac) US, B. SA Cal)'plrolloma (Palmac) e ndemic Clrrys01hcmi.1· (Gesncriaccac) LA, CA, SA Cionocisyos (Cucurbitaccac) endemic Cle1hra (Ciclh raccac) US. CA, SA Dmilla (Dil lcniaccac) endemic Freziem (Thcaccac) CA, SA

GENERA ENDEMIC TO I'UERTO RICO

Grimmeotlendw11 (Euphorbiaccac) ll Hydrulea (Hyd rophyllaccac) US, LA, CA, SA Qnii11a (Quiinaceac) SA, CA Rha11midim11 (Rhamnaceae) CA, SA Simuia (Cucurbilaccac) SA S/mlhelia (Rutaceae) B, SA Strempe/iopsis (Apocynaceae) endemic Teimcerct (Dillcniaceae) CA, SA Vibumum (Caprifoliaccae) US, CA, SA Xylopia (Annonaccae) CA, SA Zueltmia (Fiacourtiaceae) B

Cybitmllwpsis (Myrsinaceac) TABLE XVII EXAMI'LE OF Gf:NERA FOU NO IN CUDA AND I' U ERTO RICO

Cau~:ria (PalnHie)

endemic

TABLE XV TABLE XV III

EXAMI'LES OF G I:NERA \VHI Cii OCCUR ON LY ON CUOA AND HISI)ANIOLA IN GRI!ATI:R ANTILLES

EXA MPLES Or GF.~F.ItA FO UND IN CUllA AN D TilE OAt-l AMAS

Ampeloc-cras (Ulmaceae) endemic Ale/cia (Leguminosae) CA, SA Bellcmia (Gesneriaceae) endemic Bisgoeppet"lio (Gentianaceae) endemic Bonottia (Euphorbiaceae) ll Cm·podiptcra (Tiliaceae) LA, CA, SA Cltascollteca (Euphorbiaceae) end emic Cubantitus (Euphorbiaceae) endemic Curalella (Dilleniaceae) CA, SA Ekmanianllte (Bignon iaceae) endemic Eriosema (Leguminosae) CA, SA Goc/matia(Compositae) US, B, CA, SA Hucr/ea (Staphy leaceae) SA Illicium (!lliciaceae) CA, US lsidorea (Rubiaceae) endemic Jacaranda (Bignoniaceae) B, CA, SA Junipems (Pinaceae) US, B, CA Kanvittskia (Rhamnaceae) US, CA, SA Lattlanopsis (Compositae) endemic Limnocltaris (Butomaceae) CA, SA Macrocarpaea (Gentianaceae) endemic Marila (Guttiferae) L A, CA, SA Mayaca (Mayacaceae) CA, SA Mesechites (Apocynaceae) CA, SA Neomazea (Rubiaceae) endemic Neoregnellia (Sterculiaceae) endemic

Pacltyanllttt.s (Mclastomataccae) SA Paconritta (Compositae) CA, SA Paepa/mulms (Eriocaulaceac) US, CA, SA Pararlteria (Gramineae) SA Pcm (Euphorbiaceac) B, CA, SA Phiuaea (Gesncriaceac) SA Phyllo.l'l)'lon (Ulmaceae) CA, SA Picardea (Rubiaceae) endemic Piuillosa (Compositae) endemic Pimts (Pinaceae) US, B, CA Pleilwdenia (Rutaceae) endemic Prolitmt (Proteaceae) LA , CA, SA Pseudocarpidium (Verbenaceae) B Sabatia (Gentianaceae) US, CA Saugelia (Gramineae) endemic Sc/w/resia (Genlianaceae) CA, SA Scutachue (Gramineae) e ndemic Sip!tocampylus (Campanulaceac) SA Strychnos (Logan iaceac) CA, SA Tapura (Dichapetalaceae) LA, CA, SA Thouiuidium (Sapindaceae) CA Tibouchiua (Melastomataceae) LA, CA, SA Verheu/lia (Piperaceae) e ndemic Victorino (Euphorbiaceae) endemic Wigandia (Hydrophyllaceae) CA, SA

Neobmcea (Apocynaccae) endcm ic Neolhymopsis (Compositae) endemic

T ABLE XIX EXAMI'LioS O F GEN ERA FOUND IN H ISPAN IOLA AND JAMAI CA, OUT NOT llEI'OilTED IN CU BA OR PUERTO RICO

Cmtaeva (Capparaceae) CA, SA Oreopauax (Araliaceae) LA, CA, SA Symplto11ia (Guttiferae) LA, CA, SA

TABLE XX EXAMPLES OF GENERA FOUND IN HJSI'ANIO LA AND PUERTO RICO, BUT NOT REI'ORTEO FROM CUBA O R J AMA ICA

Alchomeopsis (Euphorbiaceae) SA Coetzia (Solanaceae) endemic Krameria (Krameriaceae) LA, CA, SA Morrisonia (Capparaceae) LA, CA, SA Ottoschmidtia (Rubiaceae) endemic Piptocoma (Compositae) e ndemic

Pleode11drou (Canel!aceae) endemic Quararibea (Bombacaceae) LA, CA, SA Ro/linia (Annonaceae) LA Staltlia (Leguminosae) e ndemic Terragaslris (Burseraceae) CA, SA

R. A. HOWARD

T I-l E VEGET AT ION O F T HE ANT IL LES

TABLE XX I

T ABL E XXV

FXAMI 'L~ OF GENU< A I"OUNO I N II ISI'ANIOLA ANilll ll! IIAIIAMAS. BUT NOT ON C Ull.\, JAMAICA U~ I'U[I{TO

f:.XAMI'LL"i OF (ii:NHtA \V I tiCH AI'PJ:Ail TO IJE AIJSI:Nl" FH.OM I'UI!KTO K.ICO, UUTOCCUR ON CUBA, II ISPANIOLA

ltiCO

ANI)

Tcmmthus {Compositac) endemic

Aciducrowu {Euphorbiaccac)cndcmic Ail'fu·udoll (Simaroubaccac) US, ll, CA. SA ;lreuaria (Caryophyllaccac) US, CA, SA /Jesleria {Gcsncriaccac) LA, CA · Broughtunia (Orchidaceac) endemic Brya ( Lc~:uminosac) endemic Budd/cia (Loganiaccac) CA, SA Cameraria (Apocynaccac) endemic Co.wsia (Ru biaccac) US, ll, LA, SA · Cotalp11 (Bigno niaceac) US, Asia Cimwmodcudron (Cancllaceac) SA Cyatlwla {Amara nthacc;tc) LA, CA, SA Cymbocarpit (Burma nniaccae) SA Eseubeckia (R utaccac) CA, SA Eustoma (Gentianaccac) CA, SA Forchhlllllllterio {Capparaccac) CA, SA G11rry11 (GMryaccac) US, CA Grimmeodendrou (Eup horbiaccac) D Gyrotaenill (Urticaccac) endemic

TA BLE XX !l I'XA ~ I I'LES Of G ENERA W III C H AI'I'I!AR TO liE ABSENT FROM CUBA, BUT OCCUII ON IIISI'A NIOLA, J AMAICA

AND I'UERTO RICO

Alloplectus {dcsncriaccac) LA, CA, SA Ormo.l"ia (Lcguminosac) LA, CA, SA Pouteria {Sapotaccac) LA, CA, SA Sabicea (Rubiaccac) CA, SA

Jnncns{J uncaccac) US, LA, CA, SA Ko;·u:letzkya (Malvaceac) US, CA, SA, Africa

TABLE XXIII

JA~IAlCA

J.aetia (Fiacourtiaccac) CA, SA Lagella (Thymclae<lccac) endemic Lasiocroton {Euphorbiaccac) B Letteocroton (J::uphorbiaccac)-cnctctn ic Liabum {Compositac) CA, SA Lmumia (Fiacourtiaccac) CA, SA Mascaguia {Malpighiaccac) CA. SA Neuro/aeua (Compositac) CA, SA Omplwlea (Euphorbiaccac) LA, CA , SA Oocarpon (Onagraccac) CA, SA Phyl/ostylo11 (Ulmaceae) CA. SA Pkrodeudrou (Picrodcndraccac) endemic Rmllmmlw· (R<In unculaccac) CA, SA

Samo/11;· {Primulaccac) US, B, CA, SA S teguospemw (Phytolaccaccac) CA Tttpura (Dichapctalaccac) CA, SA Triopteris (M alpighiacc:\C) B Vallesia (Apocynaccac) US, B, CA, SA Vacciui11111 (Ericaccac) US, LA, CA, SA Zuelania (Fiacourtiaccac) B, CA

EXA MI' LES OF GENERA W HIC H Al'l'EAR TO BE ABSENT FROM HI Sl'A NIOLA, BUT OCCUK ON CUUA, JAMA ICA AN D PU ERTO RICO

Holtenbergia {Bromeliaccac) LA, SA Marsypiautlw.1· {labiatae) LA, CA, SA

Disjunct distribution patterns in the Antilles

J'dicmpho/is{Sapotaceae) LA, CA

TABLE XX IV EXAMPLES OF GENERA WHIC H AP P EAR TO BE ABS ENT FKOM JAMAICA, llUT OCCUR ON CUBA, HISI'AN IOLA AND PUERTO RICO

Da/ec/rampia {Euphorbiaceae) CA, SA Didymopauax {Araliaceae) L A, CA, SA Ditta {Euphorbiaceae) endemic Doliocarpus {Dilleniaceae) LA, CA, SA Guattaria (Annonaceae) LA, CA, SA Hybauthus (Violaceae) LA, CA, SA Ixora (Rubiaceae) LA, CA, SA Jug /aus (Juglandaceae) US, CA, SA Magnolia (Magnoliaceae) US, C A, SA Me/iosma (Sa biaceae) LA, CA, SA Ottosc/rulzia (Icacinaceae) endemic Parathesis (Myrsinaccae) CA

Plraeosphaeriou {Commelinaceae) CA, SA Pilocarpus (Rutaceae) LA, CA, SA P iuus(Pinaceae) US, B, CA Prockia (Fiacourtiaceae) LA, CA, SA Proustia (Compositae) SA Rlrexia (Melastomataceae) US Scolosantlws (Rubiaceae) endemic Scrop!tularia (Scrophulariaceae) US Styrax (Styracaceae) US, L A, SA Terebraria (Ru biaceae) B, LA Tetragastris (Burseraceae) CA, SA Torralbasia (Celastraceae) endemic

l· l

T here a re many exa mples of d isjunct distribution patterns of genera between one or mo re islands of the Greater Antilles with isla nds of the Lesser Antilles, with Central A merica, o r with South America. These can be genera wi th several species in the Antilles a nd a large n umber in a distant area. Table XXVI consists of genera indigenous to C uba alone of the Greater Antilles. Only three o ft he examples cited occur also in the Lesser Antilles, fo r the more com mon range extension is to Central America and/or Sou th America. Lists for Hispaniola (Table XXVII) and Jamaica (Ta ble XXV lll) show a smaller number of genera comparably represented only on each island of the Greater Antilles. O nly two genera are cited for Puerto R ico (Table XXIX) as indigenous to that island but occurring elsewhere in Latin America. Examples of genera occurring on two isla nds of the Greater Antilles and with a disjunct distribution elsewhere are infrequent. Tapura (Dichapetalaceae) occurs on Cuba and Hispaniola, in the Lesser Antilles and South America, but is unreported from Central America. Alchorneopsis (Euphorbiaceae) is reported from· Hispaniola and Puerto Rico a nd from South America. Symphonia (Guttiferae) occurs on Hispaniola and Jamaica and is fo und in the southern Lesser Antilles as well as in Central America and South America. Cymbocarpa (Burmanniaceae) is found in C uba, Hispaniola and Jamaica and occurs elsewhere in Latin America in South America.

R. A. HOWARD

TH E VEG ETATION OF TH E ANTILLES

TABLE XXVI

TABLE XXVIII

I:XAM I'Lf.S OF (if.NEilA INDIGENOUS TO CUUA ALONE OF TilE (illFATII\ ANTILLES

l :XAM I'LES OF G[Nt'ltA INDIGENOUS TO JAM AICA Ol>.LY OF Till: Glt[ All;R ANTILLES

--- - ·- ---.

A coelorraplte( Palm<~c)

US, CA Actinostemt'll (Euphorbiaccac) LA, SA Amaitma (Rubiaccac) CA. SA Bcfm'ia (Eric<~ccac) US, CA. SA /Jeloria (Tili<~ccac) CA Bcrbcri.1· (Bcrbcridaccac) CA /Jonuetitt (Thcacc<IC) SA Brao•tti.-ia (Acant haccac) CA, SA Ca /ycophylluut (Rubiaccac) CA, SA Calyptroclu'f)/1.\' (Composilac) US, CA Cephalaurlm.\· (Rubiaccac) US, CA Clwerolepi.l' (Mclastomataccac) SA Cienfuego.ria (Ma lvaccac) US, CA, SA Cneorum (Cncoraccac) Canary lsi., Mcditcrr. Cou.mwea (Rubiaccac) CA, SA Dec/ieuxia (Rubiaccac) CA, SA Deheriania (Thcophrastaccac) CA Desmopsis(Annonaccae) CA Dmccna (Liliaceae) CA Elaeagia (Rubiaceac) CA, SA EMra (Compositac) CA, SA Eriocaulon (Eriocaulaccac) US, CA, SA Eriope (Labiatae) SA Fmxinus (Oicaccac) US, CA Gen/isea (Lcntibulariaccac) SA Gossypio.rpermum (Fiacourtiaccac) SA Harpalyce (Lcguminosac) CA, SA Helielfa (Rubiaccac) CA Helo>ir (Balanophoraccac) LA, CA, SA lsertia (Rubiaceae) CA, SA Kalmia (Ericaccae) US

Laclwamltes (Haemodoraceac) US Larluwctmlon (Eriocaulacc;oe) US Leberiua (Compositac) CA Lee/tea (Cistaccae) US Lepidesmia (Compositae) SA Lueltea (Tiliaceae) CA, SA Mamuthmm ( Po dostem~tceae) CA, SA Margarantlm.r (Solanaceae) Me/mwullws (Solanaceac) CA, SA Milleria (Compositac) CA, SA Neoma<fad)'ll (Uignoniacene) CA Oenot!tera (Onagraccae) US, SA Pam thesis (Myrsinaceae) CA Picras11w (Simaroubaccac) LA, CA, SA Pieris (Ericaccae) US Poln>retmml (Loganicene) US, CA, SA PriSJimeria ( Hippocratcaceac) CA, SA Proserpinaca (1-la loragaccae) US, SA Purdiaea (Cyrillaceae) CA, SA Quercus (Fagaceae) US, CA Rims (Anacardiaccae) US Salacia (Hippocrateaceae) CA, SA Schweuckia (Solanaceae) CA, SA Stipulicida (Caryophyllaceae) US Syugo11a1111ws (Eriocaulaceae) US, CA, SA Talauma (Magnoliaceac) LA, CA, SA Tocoyeua (Rubiaceac) SA Touiua (Eriocaulaceae) CA, SA Tric!tmpira (Compositac) CA, SA Tristiclta (Podostcmaceae) CA, SA Unciuia (Cyperaccae) CA, SA

Kegeliella (Orchidaccae) CA. SA Loci.1·tcma ( Lacistcmataccac} CA, SA MtnTomemum (Rubiaccac) CA, SA Mmulco•illa (AilOcynaceac).CA, SA Mosquiroxylou (Anacardiaccac} CA Notoptem (Composirae) CA Prioria (Leguminosac) CA Pseudocentrum (Orch idaceac) LA, CA. SA P.>ittacantlws (Loranthaccae) LA, CA, SA Pteric!tis (Orchidaccae) CA, SA Tetrorchidium (Euphorbiaccae) LA, CA, SA

TABLE XXIX f.XAMI'LES OF GENERA INDIGENOUS TO I'UERTO RICO ONLY Of THE

ANTILLE~

Gonoca/yx (E ri~accac) SA Piptocarpa (Compositae) CA, SA

Distributian patterns within the islands Cuba and Hispanio la are the two largest islands of t he Greater Antilles. They possess the largest flora, the greatest d iversity of topography, great isolation of ecological niches, the highest percentage of endemism and offer the most frequent examples of disj unci ranges. The uniqueness of the flora in various sections of Cuba (Fig.6) has been emphasized in the publications of Marie-Victorin and Leon (1942, 1944, 1956) and of Sei friz (1943). The unusual floras of Pinar del Rio and the Isle o f Pines, the_ serpentine lands of Las Villas (Santa Clara) provi nce and the mountains of the · Oriente province have received considerable attention in the past. Moscoso (1943) delimited thirteen units of geographic distribution in considering

TABLE XXVII

Lepechiua (Labiatae) CA, SA Linaria (Scrophulariaceae) NA, CA, SA Loasa (Loasaceae) CA, SA Narvaliua (Compositae) SA Pereskia (Cactaceae) CA, SA Sclerothrix (Loasaccae) CA, SA Spananthe (Umbclliferae) CA, SA Sphyrospermum (Edcaceae) CA, SA Spiracautha (Compositae) CA, SA Viola (Violaceae) NA, LA, CA, SA

----------- --------

AdclobotrJ•s (Mclastomataccac) CA, SA Ariiii'Osll!lllltW (Mclastoma taceac) CA, SA Blakea (Mclastomataccac) LA, CA, SA Calea (Compositae) CA, SA Ceplwefi.,· (R ubiaccac) LA, CA, SA Clmeuocep!ta/us(Compositae) CA, SA Chariantlws (Melastomntaccae) LA Coccoloba (paniculatc inOorcsccnt forms) SA Geissomeria (Gcsncriaccac) SA Gria.1· (Lccythidaceac) CA, SA Gynoxys (Compositae) SA Ho./finannia (Rubiaccac) CA, SA

EXAMPLES OF GENERA FOUND IN HISPANIOLA ALONE OF TH E GREATER ANTILLES

Arceutltobium (Loranthaceae) NA, CA, SA Aspidosperma (Apocynaceae) SA Castilleja (Scrophulariaceae) NA, CA Cftimaphila (Pyrolaceae) NA, CA Clavija (Theophrastaceae) CA, SA Coreopsis (Compositae) NA, CA, SA Dactylaeua (Capparaccae) SA Disciphania (Menispermaceae) CA, SA Dussia (Leguminosae) LA, CA, SA Gaultheria (Ericaceae) NA, LA, SA Halimium (Cistaceac) LA, Afr., Eur.

Fig.6. The provinces of Cuba. PR = P inardel Rio; IP = Isle of Pines; Ii = Havana; M = Matanzas; LV= Las Villas; CAM = Camaguey; OR= Oriente.

R. A. IIOWARD

Ti lE VEGETATION OFTHE ANTILLES

T/\ilLE XXX

the ot her western provi nces, but only two in eac h of Camagucy and Oriente provinces. The. sandy plains and swamps of Cuba prQ.vide the habi tat for continental North American genera such as Kalmia, Pieris, Quercus and Fraximts. The ge nera of Cuba which also occur in Central America arc predomina ntly in the Pinar del Rio province with less num bers successively in Oriente and the Isle of Pines and generally di minish in number!. in an easterly progression. Those genera of Cuba wh ich are also found in South America follow the same pattem as tha t for Central American genera in Cuba. Two well-known and striking cases of disj unct distribution of great distance are the genera Cneorum and Dracena. The genus Cneomm (Cncoraceae) is found in the West Indies only in the Sierra Maestra range on the south side of the Oriente prov ince in Cuba. lt is represented elsewhere in t he Canary Islands and the Mediterra nean region. The species Dracena cubensis (Agavaceae).is found in the Sierra de Moa range on the north coast of the Oriente province in Cuba with additional species of the genus occurring in Central America and in Africa. The island of Hispaniola cannot be d ivided into easily recognized and named provinces comparable to those of Cuba. Province or area names and boundaries have been changed frequently in the Dominican Republic following various pol itical reorganizations. The accompanyin3 map ( Fie.7) delimits nine geographic zones

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the vegetation of Hispaniola. Severa l of these represent isolated mountain ranges o!Tering ltSLia l plant formations as the southern peninsula of.Haiti extending into the Barahona province, the Cordillera Central and the Samana peninsula. Asprey and Robbins (1953) call attention to areas of specialil!ed vegetation in Jamaica as does the work of Gleaso n and Cook ( 1926) for Puerto Rico. It is possible to ta bulate the endemic genera as well as those genera indigenous to Cuba and Hispaniola cited in Tables XI , X! f, XXVI and XXV!f in their geographic position on lhe islands. The vertical columns in Table XXX represent the geographic distribution of genera within Cuba. Genera which occu r in more than one province are credited to each province. The dominance of endemic genera in the Pinar del Rio and Oriente provinces is striking. The ind igenous genera with extra-territorial relationsh ips outside the Greater Antilles are a lso more abundant in Pinar del Rio and Oriente than in other provinces. Genera which are foun d in both Cuba and Hispaniola of the Greater Antilles show a nearly uniform distribution across the length of Cuba. The Oriente province, that is closest to Haiti, does not dominate the pattern of distribution as might be expected. While the distribution by province is more uniform for genera ocfurring i11 Jamaica and Cuba, there are more example~ cited for Pinar del Rio and for Oriente than for the int~rvening provinces. The pal m gen us Gaussia is the only genus found only in Cuba and Puerto Rico. It is found in the Pinar del Rio province, the westernmost of Cuba and in the limestone western districts of Puerto Rico. The two genera which share a pattern of Cuba and the Bahama~ are found as expected on the north coastal districts in all provinces of Cuba. Four genera are cited which occur in Cuba and the Lesser Antilles. Two of these occur in Cuba and in the Oriente province alone, one in Pinar del Rio alone and one in the Pinar del Rio and Havana provinces. Of genera occurring in Cuba and the United States, sixteen occur in Pinar del Rio, ten on the I sle of Pines, five in each of

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combining several of th ose recognized by Moscoso (1943). In Fig.7, I is the southern peninsula of Haiti (Massif de !a Hotte, Massif de la Salle) extending eastward as the Sierra de Bahoruco range; 2 is the Cui de Sac in Haiti and the Enriquillo Basin in the Dominican Republic; 3 is the Cordillera Central or a central chain of mountains; 4 is the northern mountain range of Haiti, (Montagnes du Nord Ouest, Massif du Nord); 5 is the Rio del Yaque valley extending into the Cibao near Santiago; 6 is the Cordillera Septentrional ; 7 is the valley of the Rio Yuna; 8 is the plains of BayaguanaHato Mayor ; 9 is the Samana peninsula.

T H E VEGETATION OF T HE ANTI LLES

T A LILE XXX I

be fou nd on nearly every land mass in t he Ca ribbea n and some are regarded as large genera with many species within t he area. There are some disj unct dist ri b.utio n patterns rep resen ted by genera in tropical A merica and these have been commen ted upon and have often been the basis of speculation involving continental drift, lo ng-range dispcrs<d by sea or by birds or even land b ridges. T hey have not, however, been considered o n the basis of representatives within the Antj lles . · The suggesti ons o f Svenson (1933) and others of d istan t relationships between the floras of the A ntilles and the Galapagos 1slands have n ot been able t o withsta nd the scrutiny of closer in vestigation. Al though these fl oras have genera in common, the d isjunct ranges of species previously reported are now discounted by the correct naming of the specimens or by the recent collectio ns of the species in intermediate areas making the gaps in distribution less significant. T he most recent summary work on pla nt distribution is that of Good (1964): In an appendix he considers genera found ent irely or predominantly in the tropical regions, but exclud ing pan-tropical genera. He gives fo ur lists of genera which occur in the fo llowing pallerns; (1 ) America, Africa and/or M adagascar; (2) America and continenta l Africa ; (3) America and Madagascar only; (4) A merica and Asia. Of the thirty-one genera Good cites having a distribution of America, Africa and/or Madagascar the following twelve genera occur in the West Indies. Following each generic name l have indicated the total number of species cu rrently recognized in the genus (Willis, 1966) followed by t he number o f species recogn ized within the A ntillean flora. Some personal tax onom ic judgemen t is employed in the number of taxa recognized. Bertiera (R ubiaceae) 30/2; Caperonia (Eupho rbiaceae) 60/3; Carpodiptera (Tiliaceae) 80/4; Cassipourea (Rhi zophoraceae) 80/7; Eichhornia (Pontederiaceae) 7/5; Hirtel/a (Chrysobalanaceae) 95/3; Paul/inia (Sapindaceae) 180/8 ; Piriqueta (Tu rneraceae) 20/5; Sabicea (R ubia.ceae) 130/3 ; SaPia (Eu pho rbiaceae) 3 1/ 12; Symphonia (Guttiferae) 21/1; Trichi/ia (Meliaceae) 300/20. Good lists 66 genera as examples o f a distt ibution pattern of America and continental Africa . Twen ty-five of these genera have representatives in the Antilles. A manoa (Euphor biaceae) 7/ 1; Andira 75/1; Brachypteris (Malpighiaceae) 3/2; C!tlorophora (Moraceae) 12/1 ; Chrysobalanus (Chrysobalanaceae) 2/2; Coi!OC0/1Jus (Combretaceae) 2/1; Copaifera (Leguminosae) 25/1; Genlisea ( lentibulariaceae) 15/1; Gum·ea (Meliaceae) 150/7; Heisteria (Olacaceae) 50/ 1; Heteropteris (Malpighiaceae) 100/9; Laguncularia (Combretaceae) 2/ 1; Machaerium, as Drepanocorpus (Leguminosae) 150/ 1; Ma!ouetia (Apocynaceae) 25/ 1 ; Microtea (Phytolaccaceae) 10/2 ; Mayaca (Mayacaceae) 10/ 1; Parkinsonia (Legum inosae) 2/ 1; Quassia (Simaroubaceae) 40/1; Renealmia (Zingiberaceae) 75/ 10; Schultesia (Gen tianaceae) 20/2; Struchium as Sporganophorus (Compositae) 1/ 1; Talinum (Portulacaceae) 50/2 ; Tapura (Dicbapetalaceae) 20/4; Thalia (M arantaceae) 11/ 1 ; Voyria (Gentianaceae) 15/5. Four genera a re cited by G ood showing a distribution of America and Madagascar only. The genus Rheedia (Guttiferae) is now considered a section of Garcinia and

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Each of these areas rep resent a reas of speciation. In a n analysis of the selected examples o f genera of Hispaniola and their d istribution in- Latin America, several interesting patterns of plan t distribution are evident (Table XXXI). Endemic genera a re fou nd most often in the limestone mou ntains o f northern and southern Hispani ola (Fig.7,/,4). The indigenous- genera are foun d most fre quently in the sou thern peninsula area, 1, and the Cordi llera Central, 3. Genera with ranges extending into Cuba alone are most abu ndant in the southern peni nsula, 1, and to a less amount in the northern peninsula, 4.. and the dry valley, 2. N o conclusive pattern occurs in the ge nera of Hispani ola fo und also in Jamaica or the Bahamas while genera which occur also in Puerto R ico occur most frequen tly in eastern Hi spaniola. Genera with a geographic range reaching the Uni ted States occur in the sout hern peninsula, 1, and the centra l range of mounta ins, 3. The same pattern exists fo r genera of Hispan iola which also occur in the Lesser Antilles, in Central America o r in Sout h America.

Long-distance relationships and disjunct distribution patterns A number of large families of flowe ring plants are recognized as being primarily t ropical in their d istribution and of these the Acanthaceae, Ebenaceae, Euphorbiaceae, Flacourtiaceae, Ges neriaceae, Melastomataceae, Moraceae, Myrtaceae, Piperaceae, R ubiaceae, Sapotaceae, and Urticaceae are indeed well represented in the Antillean vegetation. Such genera as Casearia (Fiacourtiaceae), Cassia (Leguminosae), Chrysophyllum (Sapotaceae), Croton (Euphorbiaceae), Colubrina (Rhamnaceae), Diospyros (Ebenaceae), Eugenia (Myrtaceae), Ficus (M oraceae), Omphalea (Euphorbi aceae), Pilea (U rticaceae), Peperomia (Piperaceae) and Psychotria (R u biaceae) will

R. A. HOWARD TH E VEGETATIO N O F T H E ANTILLES

therefore a genus primarily of Asian distribution. Two genera have species occurring in the Antilles. Paepafmrthus (Eriocaulaceae) 450/ 10; and Pedifa11tftlrS 14/1. To these examples can be added such genera as Andira (Leguminosac) 75/1; Boucltea (Verbcnaccae) 39/ I ; Diocfea (Leguminosae) 50/3; Hafimium (Cistaceae) 16/2; Jatropha (Euphorbiaccae) 175/9; Kostefetzkya (Malvaccae) 30/6; Pitcaimea (Bromeliaceac) 250/1 1; Pril'{/ (Verbenaceae) 28/3; Rllipsalis (Cactaceae) 60/3; Ximenia (Oiacaccae) 19/4; Tetrorclridiw11 (Euph orbiaceae) 16/ I (Brcnan, 1965). The majority of the gel)cra cited with American-A frican disjunct distribut ion arc New World genera represented in the Antilles by single species and in Africa by single species. Sympho11ia (Guttiferac), Amanoa (Euphorbiaceae), Heisteria (Olacaceae) occur in the Lesser Anti lies and are not represented in the Greater Antilles. Bertiera (R\Ibiaceae) is foun d only in Hispaniola. Ge11/isea (Lentibulariaceae) and Ma/ouetia (Apocynaceae) are found only in Cuba, Tetrorchidium (Euphorbiaceae) is fou nd only in Jamaica. All othe1 genera are represented iri both the Grea ter and the Lesser Antilles. T he genus Symphonia (Guttiferae) is the only genus cited which has more species in Africa and Madagascar than occu r in tlw New World. The importance of Quassia (Simaroubaceae) may be questioned since the plant is both ornamental and medicinal and often cultivated and may have been introduced and persisted following cu lt ivation. The distribution and variation _of Rhipsa/is (Cactaceae) in Africa has been the subject of much discussion concerning its introduction. The problem has had advocates in theories of distribution by birds, man and continental drift, and the study Camp (1948) suggested remains to be done. Equally troublesome and unsolved is the occurrence of Pitcaimea (13romeliaceae), a large tropical Am~r ican genus in West Africa. Good cites forty genera having a disjunct distribution of America and Asia, often extending into Australasia and the Pacific Islands, and the following sixteen genera have representatives in the Antilles. T he numbers given again represent respectively the total number of species in the genus and the number in the An-tilles. Cal/icarpa (Verbenaceae) 140/17; Capsicum (Solanaceae) 50/2 ; Cedrela (Meliaceae) 6/1; Dendropauax, as Gilibertia (Araliaceae) 60/13; Heficteres (Sterculiaceae) 60/3; Ieiman thus (Graminae) 26/5; Laplacea (Theaceae) 30/1 1; Meliosma (Sabiaceae) 100/7; Mifl·eola (Loganiaceae) 6/2; Nefumbo (Nelumbonaceae) 2/ 1; Sapindus (Sapindaceae) 13/1; Schoepfta (Olacaceae) 35/ 7; Sloanea (Eiaeocarpaceae) 120/13; Symplocos (Symplocaceae) 350/21; Ta/auma (Magnoliaceae) 50/4; Turpinia (Staphyleaceae) 40/4; and Xylosma (Flacourtiaceae) 100/ 15. To this list can be added a number of genera which are well developed in Asia, although theit range may be pan-tropical or extend into temperate areas. The occurrence and development of these genera in the Antilles is of comparative interest. Antirlrea (Rubiaceae) 40/24; Chrysophyllum (Sapotaceae) 150/7; Casearia (Flacourtiaceae) 160/21; Catalpa (Bignoniaceae) 11/2; Cephaelis (Rubiaceae) 180/4; Clethra (Ciethraceae) 120/4; Dacryodes (Burscraceae) 50/l; Ehretia (Boraginaceae) 50/1; Hernandia (Hernandiaceae) 20/3; J..asianthus (Rubiaceae) 150/ 1; Linociera (Oleaceae)

100/ 10; Podocarpus (Podocarpaccae) I00/8 ; Protium (Burseraceae) 90/3; Scae•·ola (Goodcniaccae) 100/ 1; Scrophufaria (Scrophu lariaceac) 300/6 ; Styl'frx (Styracaceae) 130/4; SlrJ:clmos (Loganiaceac) 200/1; and Viburnum (Capri foliaceae) 200/4. Although these genera arc represented by one to twen ty-one species within the Antilles, all bu t Lasicmtlrus (Rubiaceae) arc better represented within Central or South America than in the Antillc~. Scae•·o/a (G oodeniaceae) in the New World is represented by a si ngle coastal species weli distrib uted around the Caribbean periphery, but poorly reprc~ented in South Ameri ca, although also found on the coast of Africa. Sapindus (Sapindaceae) has had an economic use, and its distribution may be the result of its usefulness to man. Dacryodes (Bu rsc raccae) is t he sole genus rest ricted to the Lesser Antilles in its distribution within the Caribbean archipelago.

Conclusions

The Caribbean islands form an archipelago of abou t 1,000 islands havi ng a con~ider able range in size, alt itude, soil types and environmental niches. The total fl ora is estimated to be 8,000 species and the flo ra as a whole is in great need of monographic treatments of all groups. Such studies must consider the frequent distribut ion of the genera in Central America and Sou th America as well as the Greater and the Lesser Antilles. The larger islands of the Greater Antilles have the largest number of species and the greatest amount of endemism. On the larger islands, especially Cuba and Hispaniola, there are geographic areas of high speciation and these are largely areas of mesophytic to xerophytic environments. Al though there are many small endemic genera restricted to one or a few islands, on ly two genera of more than twenty species each appear to be limited to the Anti lles. The family Picrode ndraceae with one genus and three species is the sole family restricted to the Antilles. Patterns of disjunct distribution are abundant, involving the Greater Antilles and the Lesser Antilles, the Greater Antilles and Central America, and the Greater Antilles and South America (Fig.3). There are also example~ of relationships of the Anti llean flora to Africa and to Asia. Paleobotanical studies in the Antilles are not numerous. The identification of fossil materials, however, will be a major effort in view of the complex relationships and distributional patterns of the existing vegetation.

References Alain, H., 1962. Flora de Cuba, 5. Editorial Universita ria, Rio Piedras, Puerto Rico, 362 pp. Asprey, G. F. and Robbins, R. G., 1953. The vegetation of J amaica. Ecol. Monogr., 23 :359-412. Bannister, B. A., 1970. Ecological life cycle of Euterpe globosa Gaertn. ln: H. T. Odum (Editor},~A Tropical Rain Forest. U.S. Atomic Energy Comm., Oak Ridge, Tenn., pp. 299-314. Beard, J. S.,l944. Climax vegetation in tropical America. Ecology, 25:127- 158.

R. A. HOWARD

Ocard, J. S., 1949. T he natural vegeta tion of the Windward and Leeward fslands. 0 .1 jo rd For. Mcm., 192 pp. lleanJ, J. S., 1955. The classific:llion of tropical American vegetation-types. Ecolofly, 36 :89- 100. Brcna n, J. P. M., 1965. The geographical relationships or the geriera of Lcguminosae in tropical Africa. Wcbbia, 19: 545-578. Britton, N. L. and Millspaugh, C. F. , 1920. The Bahama Flom. New York Botanical Ga rden, New York, N.Y., 694 pp. Britton, N. Land Wilson, P. , 1923/ 1924; 1925/1930. Scientific Strrl'c)' of Porto Rico and the Virgin Island;·, 5, 6. New York Acad. Sci., New York, N.Y., 5 (1923/ 1924): 626 pp; 6 (1925/1930): 663 pp. . Camp, W. H., 1948. Rhipsalis- and plant distribtltions in the Southern Hem isphere. J. N.Y. Bot. Card., 49:33- 38. Gleason, H. A. and Cook, M. T ., 1926. Plant Ecology of Porto Rico- Scientific Swwy ofPorto Rico and the Virgin Islands, 7. New York Acacl. Sci., New York, N .Y. , 96 pp. Good, R., -1964. Tile Geography ofthe Flowering Plant;·. Wiley, New York, N.Y., 518 pp. Guilding, L., 1825. An Account of the Botanic Garden in the lslaud of St. Vincent. Glasgow, 47 pp. (Now from Arnold Arboretum, Jamaica Plain, Mass.) Hodge, W. H., 1954. Flora of Dominica, B.W.L, I. Lioydia, 17:1- 238. Howard, R. A., 1953. Botanical Gardens in West Ind ies Histo ry. Card. J., 2: 11 7- 120. Howa rd, R. A., 1954. A history of the Botanic Garden of St. Vincent, British West Indies. Geogr. Re1•., 44:38 1-393. · Howa rd, R. A., 1962. Volcanism and vegetation in the Lesser Antilles. J. Amold Arboretum, 43: 279-3 11. Howard, R. A., 1968. The ecology of an elfin forest in Puerto Rico, I. fnt roduction and compositio n studies. J. Amold Arboretum, 49: 381-418. H oward, R. A., 1969. The ecology o f an elfin forest in Puerto Rico, 8. Studies of stem growth and for m of leaf s tructure. J. A m old Arboretum, 50:225-262. Howard, R. A. and Briggs, W., 1953. The vegetation on coastal dogtooth limestone in southern Cuba. J. Amold Arboretum, 34:88- 94. Howard, R. A. and Powell, D. A., 1963. The identifiCation of rubber-producing species in the West Indies. Ecan. Bot., 12:337-349. . Howard, R. A. and Proctor, G. R ., 1957. The vegetation on bauxite soils in J amaica. J. Amold Arboretum, 38: 1-41; 151-169. JacqLLin, N.J., 1797. Plant. Rar. Horti Schiinbrwm, Vietma, I: viii- xii. K irby, I. A. E., 1971. Pre-Columbian lndiam in St. Vincent, West Indies. St. Vincent Archaeol. and Hist. Soc., Kingstown, St. Vincent, 6 pp. • l eon, H., 1946. Flora de Cuba, I. Coutrib. Occas. Col. de Ia Salle, 8: 1- 441. l eon, H. and Alain, H., 1951. Flora de Cuba, 2. Coli/rib. Occas. Col. de Ia Salle, 10: 1-456. Marie-Victorin, F . and Leon, F., 1942, 1944, 1956. ltineraircs botanique dans l'i le de Cuba. Coutrib. !ns f. Bot. Univ. Mont real, 41:496 pp; 50 :410 pp; 68:227 pp. Moscoso, R. M., 1943. Catalogus Florae Domingeusis. Univ. Santo Domingo, Santo Domingo, 732 pp. Proctor, G . R., 1970. Mason River. Jamaica J., 4:29-33. Sauer, J. S., 1967. Geographic reconna issance of seashore vegetation a long the Mexican Gulf coast. Coastal Stud. lnst. La. State Uuiv., Botou Rouge, Tech. Rep., 56:59 pp. Seifr iz, W., 1943. T he plant life of Cuba. Ecol. Mouogr., 13:375-426. Stehle, H., 1945. Fo rest types of the Caribbean Islands. Caribb. For. , 6(suppl.) : 273-408. Stehle, H ., 1946. Les types forestiers des lies Caraibes. Caribb. For. , 7(suppl.) : 337-709. Svenson, H: K., 1933. Vegetation of the coast of Ecuador and Peru a nd its relation to the Galapagos Islands. Am. J. Bot., 33:394-498. Willis, J. C., 1966. A Dictionary of the Floweriug Plauts and Fems ( Revised by H. K. Airy Shaw.) University Press, Cambridge, 12 14 pp.

Chapter 2

A Paleoclimatic Interpretation of the Eocene Floras of Southeastern North America DAVID L. DILCHER Deiwrtmeu/ of Botany, Indiana i!ttil•er;'ity, Blooming/Oil, Ind. (U.S.A.)

Summary The Eocene flo ras of the Mississippi embay ment are well known through the p ublished works of Berry {1916, 1924, 1930, 1941). As part of a rei nvestigation of these Eocene floras in western Kentucky and Tennessee, thei r age, d epositional environment and paleoclimate arc considered. The age of the Lower Eocene Wilcox flora in western Kentucky and Tennessee is revised to M idd le Eocene, Cla iborne Formation, primarily on the basis o f pollen data. Berry interpreted the depositional environment of these deposits to be tropical or subtropical coastal-strand with deposition in near-shore lagoons or backwater areas. The leaf-bearing clay deposits in western Kent ucky and Ten nessee a re here recognized as oxbow lake sed iments, possibly laid down some distance from the actual embayment. The nature of the climate is critically examined by three approaches: (/) identifying ind iv id ual fossi ls to their nearest li vi ng similar forms a nd basing paleoclimatic interpretations o n the climatic range of these modern form s; (2) identifying fossils to similar living forms and analyzing the climate of the commu nities in which these living similar forms are fo und today; and (3) using the form of the fossil vegetation, its fo liar p hysiognomy, and relating this to modern climates where vegetation wit h a similar foliar physiogno my is found. Each of these approaches is analyzed in terms of its usefulness for understanding the paleoclimate of t he Middle Eocene in the upper portion of the Mississippi embayment. The fi rst two approaches are o f some value if their limitations are recognized and they are used with care. Foliar phys iognomy, when both leaf-margin analysis and leaf-size analysis are combined with temperature and moisture data, provides an important index of m odern climates and paleoclimates. The response of modern vegetation to climatic zones is discussed and the value of foliar physiognomy indexes evaluated. The approximate paleoclimate of this flora is concluded to be seasonally dry to slightly moist moisture regime, and an equable warm temperate to cool subtropical temperature regime. T he paleoclimatic conclusions drawn are based on all the available data. However, they are only approximations, since our present knowledge of the evolution of plants and plant communities and of the relatio nship of foliar physiognomy and climate is not refined enough to allow a precise statement of Early Tertiary climates .

D. L. DI LCHER

TH E EOCENE FLORAS OF SOUTH EASTERN NORTH AMERICA

Introduction

Paleoclimatic interpretations based upon fossil plants of Cretaceous to Pleistocene age have bee n d i~cusscd a great deal in the literature recen tly (Dorf, 1955, 1959, 1960, 1964, 1969; Becker, 1961; Wolfe and Hopkins, 1967; Wolfe, 1969, 1971; Axelrod and Bailey, 1969). In addi tion to these discussions specifically oriented to paleoclimates, many paleoclimatic interpretations, based on various criteria, have been included by paleobotanists in their flo ristic studies. Th ree approaches to the understanding of past climates arc frequen tly used :(/) identifying individual foss ils to their nearest living similar forms and basing paleoclimatic interpretations on the climatic range of these modern fo rms; (2) identifying fossils to si milar living forms and analyzi ng the cli mate of the comm unities in which these livi ng similar fo rms are foun d today; and (J) using the form or the fossil vegeta tion, its foliar physiognomy, and relating th is to modern climates where vegetation with a similar foliar physiognomy is. found. Tn th is discussion of the interpretat ion of the paleoclimate during the Middle Eocene of western Kentucky and Tennessee I would like to focus on all th ree : the individual components of the nora, the com munity structure of the flora and the folia r physiognomy of the flora. -

The Lower Eocene Wilcox flora, which Berry described in I916 and revised in 1930and 194 1, and the Middlc Eocene Claiborne and Upper Eocene Jackson Ooras from southeastern North America, which he described in 1924, arc the best preserved and most dive1 se floras of Eocene age known in North America. Beca use most of my work has been concerned with what Berry called the Wilcox flora I will limit this discussion, for the most part, to that flora. In his studies of t he Wilcox flora, Berry (1916, 1930) used material from 132 plant-bearing localities from Texas to Kentucky and from Kentucky to Alabama following the supposed margins of the Mississippi embayment. My research has centered on the plant-bearing beds in Tennessee and Kentucky that arc synchronous with beds Berry included in the Wilcox nora of Early Eocene age. l have examined over twenty locali ties. Recent analyses of the pollen associated with the megafossils from these localities indica te that the Lower Eocene Wilcox leaf-bearing beds in Kentucky and Tennessee are actually Middle Eocene Claiborne formation (personal communication, Robert Tschudy and William Elsik). This revision in age applies to the clay pits which are located in western Kentucky and Henry County, Tennessee, and includes such classical localities as the Puryear clay pit near Puryem, Tennessee, and the Bell City pottery clay pit in Bell City, Kentucky, but should not~~ this time be construed to be inclusive or the total Wilcox flora described by Berry (for locality list see Berry, 1930, p.40). This Claiborne flora (Berry's Wi lcox flora) was interpreted by Berry in 191 6 as a tropical or subtropical strand flora. He wrote: "Witho ut pursuing the subject in greater detai l it may be assumed to be proved that the Wilcox flora is a typical coastal flora. When i, is compared with recent coastal floras it is at once appa rent that its affin ities are entirely wi th those of tropical and subtropical America." Informalion now available makes this interpretation of the flora as a strand flora and the related clay deposits as clay lenses filling in estuary bayous, marshes, or tidal flats seem incorrect for the clay deposit.s in western Kentucky and Tennessee. Upon discussing the nature and extent of these clay deposits with those drilling for clay in the area and with Mr. William Olive (who is in charge of the U.S.G.S. Kentucky mapping project) and after observing the clay deposits in several pits in the area, it is now evident that the bulk of the known clay deposits conform to a pattern typical of old channel fills. In cross-section they resemble an old river channel 1111 and their shape, usually bent or curved, is typical of old meandering rivers or oxbow lakes. These plant-bearingclay deposits seem then to have been formed in oxbow Jakes several miles inland from the coast of the Mississippi embayment rather than to have been coastal deposits. The plant-bearing beds in Texas or other areas included in Berry's Wilcox flora may have been part of an ancient estuarian bayou as Berry (1916) indicated, but this interpretation does not seem to be valid for the deposits of clay in those pits I have studied in western Kentucky and Tennessee.

Individual co mponents of the flora ldentljiauion to modem taxa

In revising this flora, I attempted to identify leaves by a careful morphological and anatomical study in place of the "leaf matching" type of identification that commonly has been used for Tertiary leaves. Anatomical details of the fine venation and characteristics of the cuticle covering the epidermal cells, in addition to characters of the gross morphology of the leaves, were studied. Fruits and pollen were also considered. Brown (1944, 1946, 1960) pointed ou t some incorrect identifications in this foss il flora. Using the metl;od of identification descri bed above I have fou nd that about 60% of the family and generic determinations published by Berry (1916, 1930) are incorrect. Some of the revisions of the flora are the following. The genus Taxodium has been found to be a Podocarpus (Di lcher, 1969) and the entire family Proteaceae, represented by fo ur ge nera accord ing to Berry, is not present (Dilcher and Mehrotra, 1969a,b). Eight out of ten species of Sapindus are in fact one form and not allied to that genus (Dilcher, 1965) and one for m described as Aralia is Dendropanax (Dilcher and Dolph, 1970). Such major changes continue to be made as the fine venation and Âˇ cuticular features of these fossils are critically examined and, as would be expected, some new fossil plants not found previously are being added to the flora a~ new collections are made (Daghlian and Dilcher, 1971). Despite these taxonomic changes, this flora remains one of the largest Tertiary floras known in North America. Little reliance can be placed on climatic conclusions based upon the present

D. L. D ILCH ER

THE EOCENE FLORAS OF SOUTH EASTERN NORTH AMERICA

environ ments o f supposed living similar forms of incorrectly-identified fossil pla nts. In any flori stic study in which the climatic inte rpretations are based mainly uponmodern affin ities the reliability o f the in terpretat ions depends on the accuracy of the identification. Th i~, in turn, depends o n how critically the modern and fossi l forms ha ve been compared. Often only gross features of leaf shape and venation arc used; occasio nally features o f fine venation and cuticular characte!s arc considered. O nly rarely are all of these combined with a st udy of the fruits, pollen and other o rgans o f the pla nt. Any identification of fossil material wh ich relates it to specific modern taxa must be judged in light of the completeness of the in fo rmation used to make the compa rison.

and flowering has commo nly been observed for several plants which have a long north- south range. Trees such as red maple (Acer rubra) respond q uite dilierem ly at the extreme~ of their range to environmental variables. Winstead (1968) found both anatomical and physiological diflcrcm:es along t he north-south distribution o f sweet gum (Liquidamba r styraciflua)which ranges from the New England states to Honduras. There were marked diiTerenccs in germination ti me, leafin g ti me, growth and leaf abscission in this single species. These d iiTerenees are p robably great enough to exclude the H ond uran form from the New England area. Thus one should not rely too heavily on one o r t wo identi fiab le species in a fossi l flora when drawing paleoclimatic conclusion~. lf d ifferences among modern forms o f a species are great enough to exclude o ne for m from the total range of the species surely the climatic ra nges of fossil and modern forms o f a species may not be identical.

El'olution ofthefossi/taxa Several leaves in this flora presen tly cannot be identified to any extant taxon. T his could be the result of an incomplete search for simi lar modern forms or it could represent a d egree of evolution of angiosperms which has not generally been recognized. For the most part, angiosperm flo ras of the Ea rly Tertiary have been described using modern family and generic names to ind icate ari affinity with a modern fo rm . An additional level of sophistication has frequently been added by giving "modern equivalents" (Graham, 1965) or "similar living species" (Axelrod, 1966; MacG initie, 1969) for fo ssil leaves. Although classifying fossi l plants this way is often useful and convenient it tends to de-emphasize the degree o f evolutio n of these fossil forms by s uggesting that angiosperm fam ilies and genera were well-formed and co ntinuous t hrough the T ertiary to modern t imes. [ have found that the anatomy of leaves, as evidenced by variations in the cuticle, changed during Middle Eocene time. The evolutio n taking place in leaves during M iddle Eocene time is not generally evident from examining gross leaf features or fin e venation but is more readily observable in the cuticular features. Because of their excellent preservation I could use fin e features of cuticle to observe differences in these fossil leaves which are impossible-Âˇto observe in most fossil fl oras. The leaves of Dryophyllum tennesseensis and Sabilites grayanus (work in progress) have unique trichomes or _cell types which vary from one clay pit to a nother. Slight cuticular variations were also noted in leaves of Knightiophyllum wilcoxianum from two different clay pits (Dilcher and Mehrotra, 1969b). Such variations suggest that clay pits located near each other probably a re not isochronous and that some of the taxonomic units of the flora were not stable during the Middle Eocene. Axelrod (1958) illustrated the adaptation of vegetation during the Early Tertiary in response to a drying environment. Certainly individual species, genera or even families of angiosperms were not static through Tertiar y t ime. Physiological tolerances of individual specie~ and entire genera have also most certainly been modified through time. A single modern species may be quite variable in its physiological responses throughout its range ; variation in the time of leafing-out

Relation of ra11ge and ecological tolerance The range of extant genera or families is not always ~n accurate measure o f their ecological tolera nce. However, since it is often the only measure available it may be over-emp hasized in determining paleoclimatic conditio ns. We are still discoveri ng in the modern veget,ttion of temperate and subtro pical areas that some elements of the vegetation can live at more northerly latitudes when transplanted there. The Gulf Coast states, fo r instance, can support a variety of types o f vegetation which, according to present-day d istri butions, are considered to be tropical o r subtropical plants. T he palm genus Saba/ has been identi fied from the clay deposits studied (Dilcher, 1968; DaghliaJLand Dilcher, 1972). There are several modern species of Saba/, nearly all of which have been grown in Florida and observed to recover very well from rather severe winter frosts ( Henry, 1957; Smith, 1964). Thus the use of palms as a11 indication o f a tropical or subtropical climate (Berry, 19 16) is open to question. T he genus Pllilodendron i11 the Araceae has also been found in this flora (Daghlian and D ilcher, 1971). T oday species of Philodendron are distributed in the tropical and subtropical areas of the Americas. l have observed la rge-leaved philodendrons growing quite well in areas a~ far north as Baton R ouge, Louisiana; they grow along the Gulf Coast and also in southern Florida. Frosts regularly occur in some of these areas. Thus, although the mixture of palms and large-leaved ph ilodendrons at fir~t glance suggests a tropical rain forest environment, a closer look presents the possibility of a cooler and d rier climate. When dealing with ind ividuals in a fossil fl ora one should remember that the. older the flora the more time there has been fo r changes to have occurred in the morphology, anatomy and physiological responses of the organisms. When various details of cuticle and fu1e venation and pollen and fruits are investigated in the fossil record there is no indication that an angiosperm species has maintained itself through any length of geologic time. I have fo und specific changes in the fine features of the leaves d uring M idd le Eocene time. Thus, it would seem p resumptuous to make more

D. l. DILCHER

than a general suggestion of paleocl ima tes based upon the present range of ecological _ tolerances of modern species that arc related only at a gene ri c or family level to the fossil material, even if the e<.:ologica l tolcrances were accurately measured.

T ilE EOCEN E FLORAS OF SOUT HEASTERN NORTH AMERICA

The community has been the major unit used by th ose interested in recent and past responses of plants to climate. It has generally been recognized that modern commu nities are associated with specific environmenta l fac tors, with climate playing a major role, which a ffect the distribution of each type of comm unity. Modern community fo rm and composition change through space as the climate changes. This has led paleobotanists to accept the idea of the community as a un it which ha" been responsive to environmental change in a predictable fas hio n through time and thus is a good climatic indicator.

Wolfe ( 1969) have also expressed simi lar opinions of the instabili ty of a comm unity through time. Livingston's work on post-Pleistocene floras in the East African Rucnzori Mou nta ins demonstrated tha t the structure of communi ties can be seen to change through as li tt le time as the post-Pleistocene. A. W. Johnson (1968) summarized very wyll the concept of the community as it ex isted through time. He wro te: " ...the composi tion of plant communities is determined by the migrational history of species populations, Âˇby their genet icall y based physiological tolerances, and by 1heir competitive interacti ons. There is no evidence, except from special cases of symbiotic relationsh ips, for the evolution of pla nt Âˇco mmun ities by group nat ural selection. Whatever changes occur in the composit ion, struc t u re~ or location of plant communities in time arc explainable on the basis of individual organisms. Vege tation evolves only in the sense that different groups of species occur toget her at d iffe rent times and in cl iOc rent places as individu als respond differentially to the stresses imposed by changing cl imates and substrates."

Swbility t!troug!t time

Separation into equira/ent modem communities

Community structure

The Eocene community of th is fl ora seems to be a mixture of plants found in vario us commLmit ies today. We have carefully documented records of the presence of plant forms which are very similar, on a generic level of comparison, to Saba!, Philodendron, Hura (Euphorbiaceae), Ficus, Ocotea and Nectandra (Lauraceae), and legumes. Such genera migh t suggest a lowland tropica l environmen t. However, remains of leaves of Dendropanax (Ara liaceae), Dryop!ty/lum (Fagaceae), and the gen us PodocalfJIIS (Podocarpaceae), leaves, fru its a nd pollen of E11gellwrdia and pine pollen are also common in these sediments; since these are common elements in the montane areas of Central America today, they suggest somethi ng other than a lowland tropical environment. When we consider that the tropical or subtropical elements of Eocene times in the Mississippi embayment were associated _with elements which are common in the premontane-mont ane areas of Central America today, it appears most probable that associations within a community have changed as the physiological tolerances of the individ ual orga nisms and the climate of the area have been modified through time. The composition of this Eocene community seems to ind icate that a community of plants is not a sta ble association through time but rather a somewhat ephemera l collection of organisms that reflect si milar tolerances to a given environment in a general sense. As Mason (1947) points out: " Because of the differences in genetic comtitution and Âˇin physiological capacity between the various species of the community,' and because of the operation of different genetic mechanism~ it is hardly to be expected that any two or more species of such a community will follow precisely the same historical pattern even for a relatively short time. The inevitable result is that even the coincidental unity of any particular assemblage of p lants may be of short duration." Livingston (1967) and

When a basin is 1eceiving drainage from s treams which_ flow through several plant communities, material from these various communities may be mixed together in the sediments and the fossil flora fo und preserved in such sed iment may represen t fragments of several plant communities mixed toget her. Usually an attem pt is made to sort out such mixing before any paleoclimatic interpretation i~ put forward. T he basis for the divi sion of fossil floras into separate equivalent modern commu nities lies in the assumption that the physiological responses of the individuals which are sorted out into the various proposed fossi l comm unities are the same as those of si milar modern species and that the composition of plant communit ies have changed very lillie through time. There seems to be no hesitancy to accept the migration of individual species or genera th rough time and space; fossil flo ras are often published giving the percentage of simila r forms to Asian , European, African, American or other flo ras arou nd the world. H owever, as evidenced by the reliance paleobotanists put upon commun ity relationships (Axelrod and Bailey, 1969) fo r paleoclimatic conclusions, there is as yet little acceptance of the possibility that species and genera have also been changing their position within or between plant communities through time. The evolution of communities thro ugh time is best understood by a study of individuals of a fossil flo ra as completely as possible through as shor t an interval of time and space as possible. Pleistocene palynology has so far given us the best record of changing community structure throug h time (Livingston, 1967). There are also inclications from Early Tertiary t ime that floras such as the Green River flora and the Eocene floras from Kentucky and Tennessee were unique associations of plants in time. Regarding the uniqueness of t he Green River flora, MacGinitie (1969) wrote : " The

D. L. DILC HER

Green River fl ora shows no clear relat ionships with any living flora known to me. It is - a peculiar and uniq ue association." In the Eocene depos its from Kentucky and Tennessee there is evidence for mixing of forms which today arc restri cted to na rrower bel ts of lowland or montane areas. Both Gray (1960) and Brown (1944, 1960) have published papers adding genera to the fl ora which t hey believed were temperate in nature. Rather than mix these temperate forms in the so-called subtropical coastal fl ora they postu lated their source area in the Appalachian uplands. H owever, since megafossi ls as well as pollen of some of these supposed temperate forms have been found, i.e., the leaves or fruits of Dryophy!lum, Podocarpus and Engelhmdia, l think there were probably temperate forms present in the lowland com munity which we would not recognize as elements of a lowland flora today.

THE EOCEN E FLORAS Of SOUTHEASTERN NORTH AMER[CA

find a basis for paleoclimatic conclusio ns other than the taxonomic relationships of fossi l a nd modern plants and plant co m mun ities. Toward this end a study of foliar physiognomy provides some interesting insights into ecological tolerances and climate. Pe rhaps the best known study of foliar physiogno my is the work of Bailey and Sinnott ( 1915, 19 16) wh ich pointed ou t that leaves o f many woody d icotyledons a re cha racteristically entire (Fig. I) in tropical, arctic, and xeric regions and non-entire (Fig.2) in temperate regions. Leaf size has also been related to climate, often using the leaf-size classification proposed by Raunki acr (1934) and modified by Webb (1959)

Foliar physiognomy Because of the evolution o f plant form s and changes in their ecological tolerance and in the composition of plant communities through time, 'it seemed desirable to

Fig.2. Types of non-entire margined leaves. Large non-entire margined leaves or leaflets are characteristic of the mid-latitude temperate deciduous forests. Small non-entire leaves or leaflets are characteristic o f reduced levels of moisture and heat bu t not extreme reduction of either. For data, see Fig. 4- 6.

Fig.l. Types of entire-margined leaves. Large entire-margined leaves are more characteristic of warm humid areas while small entire-margined leaves are more characteristic of cool wet or warm dry areas. Functionally leaflets are most often under the same physiological stresses as leaves and t hus leaves and 1eanets are classified together. For data, see F ig. 4-6.

shown in Fig.3. Parallel evol ution of similar leaf types in unrelated plants which occupy similar environments today indicates that the evolution of various foliar types is directly cotrelated with the environment. According to Ehrendorfer (1970): "Evolutionary patterns and strategies result from t he fac t t hat all aspects of population structure and differentiation are correlated and in:fl.uenced by selection. G roups with similar variation potential therefore will tend to produce parallel syndromes of structure ... under similar environmental conditions." Thus, with some care, foliar physiognomy of a fossil leaf bed can be used as one meaningful environmental index.

T HE EOCENE FLORAS OF SOUTHEASTERN NORTH AM E RICA

D. L. DILC HER

TABLE ! LEAF SIZE CLASS A. Lcptophyll

MAX. SIZE sq. em .

0 .25

SONS

0 A

8 . Nanophyll

2 .25

C. Mocrophyll

20.25

D. Notophyll

45.0

Flam

------

182.25

F. Macrophyll

1.640.2

G. Megaphyll

no max.

B~TIRE-MARG INED l..f.Avr~~

- - -----

1 em.

E. Mesophyll

IN SOME UOOERN Fl ORAS AND COMI'ARIÂˇ WITH THII'fRAT UttE DATil (From Wolfe, 1971)

J'EI\C ENTAGES 01' SI' ECIES TIIAT IIAV!;

F 4 X area ou tlined in black

Fig.J. Leaf-size classes established by Ra unkiaer (1934) and mod ified by. Webb (1959) by splitting the mesophyll class into the notophyll and mesophyll classes. For data of leaf size in extant vegetation, see Fig. 5 and Fig. 6.

Leaf margin and leaf size are the two foliar characters discussed in this paper. Drip tips and leaf texture are difficult to assess and poorly documented in modern and fossil fl oras and therefore they were not included. Some anatomical features of leaves, such a s mesophyll t hickness, size of marginal areolae formed by the ultimate venation, number a nd condition of the stomatal apparatus, and nature and abu ndance of trichomes, may also be responsive to climatic variations. However, not enough research o n modern vegetation has been completed in this area to use suc h features accurately in determining paleoclimates.

Leafmargin analysis Following the example of Bailey and Sinnott's (1916) leaf stud ies, Wolfe (1971) presented a fairly direct correlation between temperature a nd entire-margined leaves (Table I); as temperature decreases so does the percentage of entire-margined leaves. The percentages range from 86% entire-margined leaves in tropical rain forest vegetation to 10 % entire in a mixed northern hardwood forest. However, a compilation of informatio n available from the published records of numerous researchers (Fig.4), which includes dita from 56 studies of individual forests and regions scattered over the earth, shows a mo re complex relationship. In Fig.4 the percent of entire-margined leaves is plotted in relationship to moisture as well as temperature and presented in a scheme modified from Holdridge's world life zones (Holdridge, 1967). The percentages given are often averages of data from several field sites studied in a climatic zone. The boundaries between the vegetational zones

Malaya Philippine 1slancls (200m) Ceylon (lowland) Man illa East Indies Philippine Islands (450 m) Hawai i (lowland) Ceylon (upland) Philippine Islands {700 m) Hong Kong Hainan (lowland) Philippine Islands (1 ,100 m) Taiwan (0-500 m) Hawaii (upland) Hainan (upland) Fukie n {upland) North Kwangsi Taiwan (500- 1,000 m) Ta iwan (I ,000- 2,000 m) North Kiangsi South Anhwei North Chekiang East Szechuan- West Hupch South Kiangsi Northern China Plain Shensi Manchuria

Percent M.A.T. M.A.R. emire 86 82 81 81 77 76 75 73 72 72 70 69 61 57 55 50 49 47 41 38 36

28 26 27 27 26 26 24

I 4 2

24 22 24 23 21 16

1 13 II 2 II 4

19 19

19 12

30 24 22 22 10

3 3

5 4

Vegetntion tropical rain forest tropical rain forest tropical rain forest tropical rain forest tropical rain forest tropical rain forest paratropical rain forest submontanc rain forest submotltane rain forest paratropical rain forest paratropical rain fo rest monta ne ra in forest paratropical rain forest montane rain forest subtropical forest subtropical forest subtropical forest subtropical forest subtropical fo rest mixed mesophytic forest mixed mesophytic forest mixed mesophytic forest mixed mesophytic forest mixed mesophytic forest dccidLIOus oak forest deciduous oak forest mixed northern hardwood forest

M.A.T. = mean annual temperature; M.A.R. = mean a~n~t a l range _of _temperature. Leaf-margin data after Bailey and Sinnott (19 16) and Brown {1919), or ongmal comp1lattons based on Wang (l 96!) and Li (1963). (From Wolfe, 1971; with permission).

are not absolute since thes~ zones are continuom with one another in nature. The s mall figures in the upper corners of each zone are the minimum and maximum percentages ef entire margins found in the field sites for that climate and, as would be _expect~d, because of local ecological differences in the study sites the range of percent of e ntire margins sometimes overlaps from one climatic zone to another. It is evident from Fig.4 that the percentage of entire-margined leaves decreases as the climate cools, dries, or cools and dries. In paleoclimates it is often impossible to distinguish between the part temperature and moisture played in producing types of leaf margins since both factors have similar effects. Those zo~es ha~ing 55-H)?% entire margins have either high levels of temperature and varymg mo1sture or h1gh levels of moisture and varying temperature. Only those zones which have both reduced levels of temperature and moisture have lower percentages, 10-50%, of

D. L. DILCHER

Subpolar

Alpine

Boreal

Subalpine 9

Cool

temperate

Subpolar

Alpine

Boreal

Subolpine

TH E EOCENE FLORAS OF SOUTII EASTERN NORTH AMERICA

Montone

Cool

t empe~ote

Warm

37 -45

temperate

52 59

67 52

64 72

Subtropical

Lower

montane

Worm temperate

l ower montane

Premontcne Subtropical

Tropical

loesert

Dry

S. dry

10076

Moist

Wet

Tropical

Tr-opical

Tropical 7

Dry

S.dry

R.oin

Desert

Fig.4. Average percent of entire-margined leaves in relation to temperature and moisture. The extremes of entire margins for each clima tic zone arc indicated in the upper corners of the box for each zone. Climatic zones a rc given as a func tion of temperat ure and moisture in Fig. 4-6 for convenience, while it sho uld be realized that such a simple figure represents only a generalization of such zones to zones of vegetation. S. dry= scasonally dry. Cha nges in altitude in low-latitude areas should not be interpreted from this figure as being equated with changes in latitude at low-allitudes. For further explanation, sec text. The following references were used in compiling the data used in Fig, 4-6: Bai ley and Sinnott (19 16); Beard (1946); Brown (19 19); Cain et al. (1 956); Dolph (1 972); Gentry (1969); Howard (1969); Petit (1968); Richards (1966); Tasaico (1959); Webb (1959); Wolfe ( 1971).

Wet

Rain

Fig.5. The lower centra l number in each zone is the average leaf length. The average percent of each leaf-size class is given from left to right leptophy ll and nanophyll, microphyl l, notophyll, mcsophyll, macrophyll and megaphyll~in the upper half of each zone. S. dry=scasonal ly dry.

Subpolar

Alpine

Boreal

Subalpine

entire-margined leaves. T he fact that available moisture affects the percentage of entire-margined leaves, as much or perhaps somewhat more than tern pet ature, makes the relationship of leaf margin to clima te more complicated than Wolfe's ( 1969, 197 1) correla tion of entire margins a nd temperat ure suggests.

Cool te'Tl'erote

Leaf-size analysis

temperate

A correlation of leaf size and climate shows that both temperature and moisture also influence this relat ionship (Fig.5,6). The leaves of several modern forests were ranked accordi.ng to the leaf-size classes proposed as a measure of leaf area by Raunkiaer (1934) and modified by Webb (1959; Fig.3). There a re a total of seven leaf-size classes; however, in this stud y so few leaves were fo und in the largest (megaphyll) and smallest (leptophyll) size classes that the data from these classes were included in the classes macrophyll a nd nanophyll, respectively. Thus in Fig. 5 only five leaf-size classes are given for each climaric zone. A general trend in the reduction of

Moist

79{21

Warm

7/93 23/77

60{40 82/16 76{24

Subt ropÂˇ,cal

30/60

78/22

Tropical

Desert

Dry

57/43

Moist

Lower montane

85/15 88/12 Pr e montane

70/30 80/'J!J 84/'16

S.dry

Montone

Wet

89/11 Tropical

Rain

Fig.6. The average percent of large leaves over the average percent of small leaves is given for each climatic zone. For explanation of large and small leaves, see text. S. dry = seasonally dry.

D. L. DlLCHER

leaf size ca n be seen by the increasing percentage of smaller lea f-size classes in the various zones as their temperature or moisture decrease from the maximums of the tropica l rain forest. Average leaf lengths (given in Fig.S when available) also show a marked decrease as temperature 'and/or moi stu re decreases. Fig.6 simplifies the leaf-size class data given in Fig.S to two numbers for each zone, the upper number representi ng the percent "large leaves" and the lower number the percent "small leaves". In calculating these percentages the leaf-size classes notophyll, mesophyll, macrophyll and megaphyll were designated as "large leaves" and the leaf-size classes leptophyll, nanophyll and microphyll were designated as "small leaves". This is an arbitrary and artificial designation and the data is less exact than that presented in Fig. 5. However, its use in Fig.6 facilitates observation of overall trends in leaf size through cl imat ic zones and shows quite clearly the reduction of leaf size in response to reduced levels of temperature and/or moisture. The wet n opics are characterized by a high percentage of large leaves; as the climate dries or cools" the percentage of large leaves decreases. Thus leaf size is, in a general se nse, a measure of climate. However, the same problem exists in the use of lcafsize to determine paleoclimates as existed in the use ofleaf margin, the problem of trying to separate out the infl uence of moist ure and temperature. Wolfe (197 1) has been co ncerned with both leaf margin and leaf size. Concct ning these he wrote: "Leaf-margin analysis cannot, of course, be the sole criterion for determination of past climates. Other features, e.g., leaf size ... are useful but are difficult to quantify in regard to fossil assemblages. The difficul ty stems primarily from selectivity of the depositional environment; large leaves obviously will, in many environments, tend to be fragmented by turbulent currents and hence be under-represented. Another problem is th at fossil assemblages may conta in an over-representation of stream-side plants ... thus, steno phyllous plan ts that typically fall into the low size-calsses (Richards, 1952 [1 966]) may be over-represented. Such over-representation would yield an analysis indicating a cooler climate in the instance of a leaf-size analysis, as it may also in the instance of the leaf-margin analysis... The distribution of leaf-size classes in a fossil assemblage is a valuable adj unct to the leaf-margin analysis but can hardly be considered as free from selectivi ty of the depositional environment as can the leafmargin anal ysi s.'~ Wolfe's (1971) assumption that small leaves will be over-represented in basins of deposition, does not seem to be true in the clay deposits of Kentucky and Tennessee. I have fou nd leaves measuring 25 x 36 inches deposited with leaves measuring -} x 5 inches. The Puryear locality has a mixture of leaves of many sizes as illustrated by Berry {19 16). The observation that small leaf-size classes are typical of the linear or lanceolate (stenophyllous) leaves (Richards, 1966, p.85) along stream sides is an assumption by Wolfe that these leaves are smaller in total leaf area than those in the forest. No critical studies have been made of the leaf-size classes of modern streamside vegetation which supports these assumptions. Quite to the contrary, Gentry

T H E EOCEN E FLORAS OF SOUTHEASTERN NORT H AMER ICA

(1969) fou nd fewer small-size leaves in the gallery forest than in those areas removed from stream sides in the tropical dry fores t areas of Costa Rica. Thus, the use of leafsize analysis may be less selective a nd 111orc valuable than Wolfe thought. ln any case, the best analysis must result when both leaf size and leaf margin are considered . A precise understa nding of the relationship of foliar physiognomy and paleoclimate will be made possible only when both leaf ma rgins and leaf size o r fossil floras are correlated with detailed studies of the physiognomy of extant vegetation. Webb (1959) recognized that both leaf size and percentage entire-margined leaves varied with latitude and altitude. Both Wolfe (1 969, 197 1) and Axelrod and Bailey (1 969) have used th is information and emphasized the direct relationship of the decrease in entire-margined leaves and their size in response to the cooler clim ate that is associated with an increase in either altitude or latitude. However, this relationship is complicated by the fact that, in terms of pet cent of entire margins and leaf size, a change in altitude in the tropics or s ubtropics canno t be exactly equated with a change in latitude from the tropics to the tundra. As Troll (1968) poi nted out: " .. . the opinion that the same te mperature zones arra_nged horizontally in belts from the equator to the poles correspond exactly with the vertical stratification of temperature in tropical mountains is widely spread ... The fundamental differe nce between temperate and cold latitudes of the Northern Hemisphere and temperate and cold altitudinal regions in the tropics is based on the diverse temporal nature of temperature in both these atcas ... The result is as follows: in polar regions there are purely seasonal temperature climates, wh ile in equatorial regions there are purely diurnal temperature climates from sea-level up to high altitudes." The type of accommodation to climate which is made by a leaf may be quite variable. Dwarf evergreen shrubs grow ing in tropical mountain floras of high altitude in a cool frost-free climate have evo lved many small leaves. In these forests the accommodation has been one of reduction of leaf size with an evergreen habit. In the temperate deciduous forests which have alternating cold and warm seasons the leaves are much larger when tl1ey are functional in the warm season and then are dropped when the cold season begins. The relationship between the percentage of entiremargined leaves and leaf size is thus very different in cool equatorial montane evergreen forests (82% entire-margined, leaf size 77/23) and seasonally cold mid-latitude temperate decidu ous forests (15% enti re-margined, leaf size 21/79 ; Fig.4 and 6). It becomes evident that the physiological pressures operating upon the vegetation and thus the type of accommodation which the leaf has developed are very different in low-latitude montane areas than in the mid-latitude vegetation. Interpretation offoliar physiognomy

It bas been more than 50 years since the ground work for foliar physiognomy (Bailey and Sinnott, 1916) was laid and still almost no detailed field analyses have been made to test the hypothesis presented at that time. Until_this is done, these observations of

D. L. DILCIIER

the variatiom of foliar phy~i og n o my in relation to climate cannot be used as precise tools but only as general gu idelines in paleocl imatic interpretations. T he one distinct adva ntage of the usc of foliar physiogno my is that it is inclepcnclcnt of taxonomy and therefore removes the possibility of incorrect identifica tions of the fossi l materia l confusing the data. However, this advantage is lost when pollen, wood, fr uit a nd seed, 9r any other non-leaf remains are converted to percentage s of entire margins. In th is case taxonomic confusion is compounded by the assumption that leaf form has remai ned constant th rough time. Any data derived by this means should be viewed with cautiOJL Dolph ( 1972) found significant variations in the percen t of species (12-33 %) with entire margins in Ind iana forests. T his variation was dependent upon the area of sampli ng and he writes: " ... j ust as the variability of the site of study is the sum of all the quadrates and docs not indicate the variability of its parts, the regional flora is the sum of many di fferen t plant associatio ns, and its util ity is limited by its internal variability." T he leaves in fossi l leaf floras arc often derived mainly from plants living ncar the basin of deposition and represent a rathet restricted sampling of particular environments whose temperature, moisture and soil factors were probably not uniform over large areas. Thus, regional floras, which encompass a host of special e-nvironments, cannot be a very exact ba.is for determining lochlly-dcri ved fossil floras. The data given by Wolfe (1969, 1971) is based upon regional vegetation st udies and the data given in Fig.4- 6 is based upon a mixture of regional (17 sa mples) and local (39 samples) vegetation studies. Although indication s of general trends are evident in this data there are not enough local vegetationa l studies of the ecology of foliar physiognomy to use it as a basis for precise paleoclimatic interpretat ions at this time. Continued work on the physiological importance of leaf margin and leaf size such as Gates ( 1968) has undertaken will aid our understand ing of the relationships of leaf fo t m with climate and position in the forest canopy. Theoretical models of leaf form have been proposed by Horn (197 !). This shou ld play an important role in directing attention to the need for specific-field studies to test his hypotheses. As the relationships of leaf form to the physiology of the plants and the variability in climate, soil, solar radiation and other factors become known, foliar phy5iognomy will become an increasingly importa nt tool for paleoclimatic analysis.

Application to this.ffora The Middle Eocene flora under consideration in this paper is characterized by a high percentage of entire-margined leaves (82% entire; Table II). On the basis of the leafmargin percentages, Wolfe (1969) and others have classified the Eocene forest of the Mississippi embayment as a tropical rain forest. Howevet, on the basis of the leaf-size percentages (37 % "large leaves"; Fig.6) these leaves clearly do not resemble a tropical rain forest or any other type of tropical vegetation.

THE EOCENE FLORAS OF SOUTHEAS TERN NORTH AMERICA

TAI.!LE 11 FOLIAH I'IIYS IOGNOMY lli\TA FOI\

Til~ \VILC::OX AND CLAIIlOitNE FLORAS I'UIILISIIEO IIY llf.ltllY (1916, t924,

t930)

Fornwlion

Sample

A 1'CJYtge lcn~r:th

%entire

%large /l!a,,es %small lea,,es

37/63 31169

(em) Wilcox

Claiborne

321 57

9.2 8.9

No modern tlora, in my sampling of extant vegetation (Fig. 4-6), matches the fo liar physiognomy of this fossil flora. T he leaf size is mo~t similar to the leaf size of subtropical seasonally dry or warm temperate moist fores ts while the percentage of entire-leaf margins is closest to that of the tropical or subtropica l wet or rain fo rests. Since leaf margins are influenced both by temperature and moisture, the uniformity of temperature and the seasonal availab ility of moisture during the Middle Eocene in the Mississippi embayment may have produced leaf margin5 rhat give an impression of a warmer climate than actually existed. The data presented here (Table II) suggest very strongly that the Eocene forests of theM ississippi embayment were not tropical.

Additional evidence

Wood Fragments of both gymnosperm and angiosperm wood arc often found associated with leaf rema ins in the clay pits sampled in Kentucky and Tennessee. This wood is usually somewhat compressed and disto rted ; however, when it is sectioned, growth ri ngs can be ~een. As growth rings a1 e often associated with seasonality in temperature, moisture, or botli, there is a good probability that some seasonal fluxuations of temperature and/or moisture were afrecting plant growth in the Mississippi embayment during the Middle Eocene.

Pollen Limited informatio n is available abou t the plant microfossils associated with the Eocene clay deposits of the Mississippi embayment. In studies which have been made (Gray, 1960; Jones, 196 1; Elsik, 1965; Nichols, 1970) several temperate genera such as Pinus, Alnus, Betula, Castanea, Cory/us, Nyssa and Tilia have been identified. Castanea is one of the most common pollen types in the clays of Arkansas (Jones, 1961) and Kentucky and Tennessee (W. C. Elsik and D . L. Dilcher, work in progress). The abundance of Castanea pollen in all of the clay samples studied suggests that this pollen came from wind-pollinated trees. According to Faegri and Vander Pijl (1 966),

D. L. Dt LCHER

tropical species of Castanea arc insect-pollinated and would not be expected to yield abundant pollen. Tht1s, tltc abundance of Castanea pollen in these sediment s is an indirect indicat ion that a somewhat temperate climate was present in the Mississippi embayment area during the Middle Eocene. T he presence in the pollen record of th is Middle Eocene flora of temperate genera associated with tropica l genera raises the q uestion of community stability and the stability of ecological requirements of ind ivid ual ge nera t hro ugh time discussed earlier in this pa per. After studying in detail t he pollen of the Wilcox in Texas, Nichols (1970) determined that : "Plant community structure and ecologic interactio n of species could not have been exactly the same in Early Tertiary time as it is now, because at least some different plants were involved ... the palynoflora of the W ilcox Group in Texas supports the interpretation of the Early Tertiary flora of the region as one of warm-temperate to subtropical character that co-existed with a more temperate upland fl ora, which lay at some distance from the Gu lf Coast, probably in the southern Appalachian Mountains." The Appalachian highland is often used to explain the . presence of temperate form s in the sediments of the Mi ssissippi embayment and may be a valid explanation for the presence of some pollen such as Pinus which is not yet reported as a megafossil and might have come from upland plants rather d istant fro m areas of deposition. However, Nyssa, another temperate form in the. pollen record, also occurs commonly as a mega fossil ( Dilcher and McQuade, 1967) and probably could not be explained as having come from the Appalachia n highlands.

Paleoclimatic interpretations In 1916, Berry in terpreted the climate of the "Wilcox" flora to have been a frost-free subtropical climate similar to that of the -present-day Florida Keys. Later, after having traveled to the American tropics, llerry qualified his interpretation when he wrote the introductio n to the volume on the Middle and Upper Eocene floras of southeastern North Ame1ica, which was written in 191 7 but not published until1 924: "At the time this report was written, my botanical experience was restricted to the United States, and I based most of my ecologic or climatic deductions on the literature, which later studies, made in the Tropics, proved to be somewhat misleading or erroneous, and I am now convinced that most paleobotanists, nearly a ll of whom have been dwellers of the Temperate Zone, have been similarly mislead. Since 19 17 I have had an opportunity to see the living flora in the Antilles, in Central America, and particularly in tropical Bolivia and Peru. I came back from that region with the conclusion that none of the fossil floras of the Temperate Zone that paleobotanists have termed tropical are in the strict sense of the word "tropical". Most of these fossil floras contain representatives of numerous genera tha t are now confined to the

TH E EOCENE FLORAS OF SOUTHEAST ERN NORTH AMERICA

Equatorial Zone, but many of these genera a rc large and conta in species that are adapted to a variety of habitats." Vario us approaches to tmderstanding past cl ima tes have been consid ered in th is paper. The usefulness of relyi ng upon individual components, associ ations of vegetation, and foliar physiognomy to ascertain paleoclimates has been assessed . All are o f some value when used properly, and all were considered in order to an ivc at the best approximation o f paleocl in)ate for this Eocene fl ora. Equal in itnportancc to the evidence used are the techniq ues of analyzin g that evidence. Errors in fossil identification, lack o f understanding of associations of vegetation and the misapplication of foliar physiognomy can easily prod uce incorrect interpretations o f paleoclimates. An attempt was made to avoid these pitfalls in Âˇmaking the followi ng interpretations. The approximate climate of this fossil flora bordered on seasonally dry to slightly moist moisture regime and an equable warm temperate to cool subt ropical temperat u re regime. T here were p robably frosts in the nearby upland areas that only rarely invaded the lowlands. The Appalach ian and Ozark highland areas were not far away and probably supported a more temperate vegetation which mixed with the lowland vegeta tion to form quite different communit ies than exist today. I use the words "approximate climate" because this interpretation is o nly a n approxi mation derived from a synthesis of a large amount of information which seems to support my conclusions. However, none of the techniques used in this analysis are yet sufficiently developed to provide a n absolute basis for an exact description o f the paleoclimate. The "state- of-the-art" in interpretation of paleoclimates from plant fossi l material is at a level to provide good approximations only, with the expectation that o ur ability to interpret past climates will improve as more precise data on the nature of fossil and modern vegetation becomes available. Re ferences Axelrod, D. I., 1958. Evolution of the Madro-T ertiary geoflora. Bot. Rev., 24:433-509. Axelrod, D. I., 1966. The Eocene Copper Basin flora of northeastern Nevada . Univ . Cali/ Pub/. Gea/. Sci., 59:1-83. Axelrod, D. and Bailey, H. P., 1969. PaleotemperatureanalysisofTertiaryftoras. Pa/aeogeogr. Pa/aeoclimatol. Palaeoecol., 6:163-195. Bailey, I. W. and Sinnott, E. W., 1915. A botanical index of Cretaceous and Tertiary climates. Science, 41 :831-834. Bailey, I. W. and Sinnott, E. W., 1916. The climatic distribution of certain types of angiosperm leaves. Am. J. Bot., 3:24-39. Beard, J. S., 1946. The natural vegetation of Trin idad. Oxford For. Mem., 20: 152pp. Âˇ Decker, H. F ., 1961. Paleobotanical record of solar change. Ann. N.Y. A cad. Sci., 95 :684-687. Berry, E. W., 1916. The Lower Eocene fl oras of southeastern North America. U.S. Geol. Surv., Prof. Pap., 91:481 pp. Derry, E. W., 1924. The Middle and Upper Eocene floras of southeastern North America. U.S. Geol. Surv.,Prof.Pap., 92:206 pp. Berry, E. W., 1930. R evision of t he Lower Eocene Wilcox fl ora of the southeastern States. U.S. Geol. Surv.,Prof. Pap., 156:196 pp.

D. L. DI LCHER Berry, E. W., 1941. Adclilions to th" Wileox flora from K"ntucky and Texas. U.S. Geo/. Sun•., Prof l'aJI., 193 E:83-·99. Brown, W. H., 19 19. Vq;ctation of Philippine Mounta ins. Manila, Pub/. Dept. Ag ril'lll. Nat. Re.\'llllr<·es, I : 1-434. Brown, R. W., 1944. Temperate s1x:cics in the Eocene !lora of the southeastern United States. Waslt. tlcad. Sci. J., 34:349-35 1. Brown, R. W., 1946. Alterations in some fossil and living noras. Wasil. Acad. Sci. J., 36:344-355. Brown, R. W., 1960. Cork wood in I he Eocene no ra of the southeastern United States. J. Pa/eomol., 34:429-432. Cain ,S. A., Oliveira Castro, G., Murca Pirez, J. and Tom;ts da Silva, N., 1956. Applicat ion of some phytosociologicaltcchniques to Brazilian rain fores1. Am. J. Bot., 43:91 1-941. Dagh1ian, C. P. and Dilcher, D . L. , 197 1. Pltilodendi'On1eaves from Eocene sediments in Tennessee. lndiana A cad. Sci., 80; 95-96 (abstr.). Dagh1ian , C. P. and Dilcher, D. L., 1972. Middle Eocene saba loid i)Hirns. Indiwra Acad. Sci. (in press). Di1cher, D. L., 1965. Sapindaceous leanets from Eocene deposits of Tennessee. Am. J. Bot., 52(6) p.639. (abstr.). Dilcher, D. l., 1968. Revision of Eocene p alms from southeastern North America based upon cut icular analysis. Am. J. Bot., 55:725 (abstr.). Dilcher, D. L., 1969. Podocarpns from the Eocene of North America. Science, 164:299-30 1. Dilcher, D. L. and Dolph, G. E .. 1970. Fossil leaves of Dendropanax fro m Eocene sediments of sout heastern North America. Am. J. Bot., 57: 153-160. Dilcher, D. L. and Mehrotrn, B., 196%. A re-evaluation of Early Tertiary North American Proteaceae. Int. Bot. Con,l{l'., 1/tlt, Abstr., p.47. D ilcher, D. L. and Meh rotra , B., 1969b. A study of leaf compressions o f Knighriophyllwn from Eocene deposits of southeastern North America. Am. J. Bot., 56:936-943 Dilchcr, D. L. and Me Quade, J. M., 1967. A morphologica l s tudy of Nyssa endocarps from Eocene deposits in western Tennessee. Bull. Torrey Bot. Club, 94:35- 40. Dolph, G . E., 1972. A comparison o f local and regional leaf characteristics in Indiana. Indimw Acad. S ci., 80:99-103. Dorf, E., 1955. Plants and the Geologic Time Scale. In: Cmst of the Ettrtft-Geol. Soc. Am., Spec. Pap., 62:575-592. Dorf, E., 1959. Climatic changes of the past<lnd present. Contrib. Mus. Pa/eontol. , Unil'. Mich., 13: 18 1-210 Dorf, E., 1960. Climatic chan ges of t he past and present. Am. Sc ientist, 48:341-364. Dorf, E., 1964. The use o f fossil plants in palaeoclimatic interpretations. In: A. E. M. Nairn (Ed itor), Problems in Palaeoclimatology. lnterscience, London, pp.1 3- 3 1. Dorf, E ., 1969. Paleobotanical evidence of Mesozoic and Cenozoic climatic changes. North Am. Poleontol. Coni'., Clticago, Proc., A: 324-346. . · Eh rendorfer, F ., 1970. Evolutionary pallernsand strategies in seed plants. Taxon, 19:185-195. Elsik, W. C., 1965. Palynology of tlte Lower Eocene Rockdale Formation, Wilcox Group, Milam ond Robertson Coulllies, Texas. Thesis, Texas A. and M. Univ., College Statio n, Texas, 197 pp. Faegri, K. and Vander Pijl, L., 1966. Tlte Principles of Pollination Ecology. Pe rgamon, New York, . N.Y., 248 pp . Gates, D. M., 1968. Transpiration and leaf temperature. Ann. Rei'. Plant Phys., 19: 21 1-238. G entry, A. H ., 1969. A comparison of some leaf characteristics of tropical dry forest and tropical wet forest in Costa Rica. Turrialba , 19:4 19-428. G raham, A., 1965. The Sucker Creek and Trout Creek M iocene floras of southeastern Oregon. Kent Stale Univ. Bull., Res. Ser. IX, 53: 147 pp. Gray, J., 1960. Temperate pollen genera in the Eocene (Claiborne) flora, Alabama. Science, 132:808810. Henry, M.G., 1957. Saba/ minor in Pennsylvania. Principes, 1:124-125. H oldridge, L. R., 1967. Life Zone Ecology. T ropical Science Center, San Jose, Costa Rica, 206 pp. H orn, H. S., 1971. The Adoptive Geometry ofTrees. Princeto n Univ. Press, Princeton., N.J., 144 pp. Howard, R. A., 1969. The ecology of an elfin forest in Puerto Rico, 8. Studies of stem growth and form of leaf structure. J . A m old Arboretum, 50 :225- 262.

T ilE EOCEN E F LORAS 0 1' SOUTHEASTERN NORTH AMER ICA

Jonhson , A. W.. 1968. The evolution of desert vegeta tion in western Nort h America. In: G . W. Brown J r. (Ed itor), lk1wt 1/io/ogy, I. Academic Press. New York, N.Y., pp.IO I- 140. Jones, E. L., 1961. Plant Jl4itTojil.uils of the Lamililtled Sediment.l'<l/'thc Lvuw l:.ucenc Wilwx Group in Soutlt-Cemral Arkonms. Thesis, Un iv. of Ok1:tho'ma. 125 pp . Li, H. L., 1963. Woody Flom oj'Taiwan. Livings ton and Morris A rboretum, Narbcth, l'a., 974 pp. Livingston, D. A., 1967. Postglacial vegeta tion of the Ru wenzori Mountains in equatoria l Africa. £col. Morw~:r., 37:25-52. MacGinitie, 1-1. D., 1969. The Eot-cnc Green Ri ver n ora of no rt hwestern Colorado and northeastern Utah. Univ. Calif Pub/. Ge~Jl. Sci., 83 :1-140. Mason, H. L., t947. Evolution of certain lloristic associations in western North America. Ecol. Mouogr., 17:201-2 10. Nichols, D. J. , 1970. Palyuulog)' in Helatiun to Depositional En•irouments of Lignite in the Wilcox Croup (Early TenimJ•) in Texa.v. T hesis, Pa . Sta te Un iv., 467 p p. Petit, P. M., 1968. Algww.v Caracteristim.< de las N ojas de Arboles en 7i·es Tipos de BO.I'CJIW Tropicales de Bajum. T hesis, lnst. l nteram. Cicncias Agricolas de Ia OEA, Turrialba, Costa Rica, 88 pp. Raunkiaer, C., 1934. Tire Life-fo rms uf Pfrmt.v mul Statistical Plaill Geogmplty. Oxford University Press, Oxford . 632 pp. Richards, P. W., 1966. The Tropical Rain Forest- au Ecolot:ical Swdy. Cambridge Univ. Press, Cambridge, 450 pp. Smith, D., 1964. More about cold tolerance. Principes 8:26-39. Tasaico, H., 1959. La Fisionaomia de las Hojas de Arboles en Algnner Formacioner Tropicalcs . T hesis, lnst. lnteram. C icnc ias Agricolas, T urrialba, Costa Rica, 88 pp. Troll, C., 1968. The Cordilleras of the tropical Americas- aspects of climate, phytogeographical and agra ria n ecology. 1n : C. T roll (Edi tor), Ceo-Ecology nf the Mountainous Regions of the Tropical Americas. Fen!. Dlimmlcr, Bonn, pp.l5-56. Wang, C. W., 1961. The forests of China . Hai'l'ard Unil'. , Pub/. Maria Moore Cabot Fouud., 5: 1-3 13. Webb, L J ., 1959. A physiogno mic classific.11ion o f Australian rain forests. J. £col., 47:551- 570. Winstead, J. E., 1968. Ecotypic Di./]eremiation in Liquidambar styracif/ua. T hesis, Univ. of T exas, Austin, Texas. 148 pp. Wolfe, J . A., 1969. Paleogene fl oras from the Gulf o f Alas ka region. Openfile Rep., U. S. Dept. lnterior Geol. Sun•., 110 pp. Wolfe, J. A., 197 1. Tertiary c limatic nuctuations and methods of analysis of Tertiary floras. Pa/aeogeogr. Pa/acodimatol., Pa/aeoeco/., 9:27-57. Wolfe, J. A. and Hopkins, D. M., 1967. Climatic changes reco rded by T ertiary land floras in northwestern North America. In: Kotara Hatai (Editor), Tertiary Correlations ami Climatic Clumges intlte Pacific. Sasaki, Scndai, pp .67- 76. -

Clwpter 3

Âˇ

Geographical Relationships of the Flora of Mexican Dry Regions1 J. RZEDOWSKI

Escuela Nacional de Ciencias Bio/ogicas, lnstilulo Politl!t:nico Nacional, M ''xico D.F. (Mexico)

Summary Using Preston's {1962) for mula for the coefficient of similarity, the flo ra of Mexican dry regions is analyzed as to: {I) the relationships between diflerent arid zones of the country; {2) the relationships with other arid zones of the world; (3) the relationships with zones of non-arid climate. Such analyses show that in the studied flora southern affinities dominate amply over northern ones and there is evidence to believe that Mexican xerophytes derived independently from most of their counterparts in the western United States. The study finds also significant floristic ditfer!}nces between some of the Mexican dry areas.

Introduction Because of its innumerable implications of theoret ical and practical interest, the elucidation of Earth's geological history is one of the fundamental themes of modern scientific research. An outstanding, although still little advanced aspect of paleoclimatology is the determination of geograph ical and chronological distribution of arid regions during Earth's history. Our relative ignorance in this particular field i>due to t he fact that plant and ani1ml remains are the main indicators of paleoclimates, and that drought conditions, in general, are unfavourable for the fossilization of organisms. Consequently, this tool is only in minimal degree useful fo r documentat_ion on aridity ill passed epochs. In the virtual absence of paleontological evidence, other procedures, mostly indirect, become important in a search for information on dry climates of the geological past. One such p rocedure consists of a phytogeographical analysis of the floras of modern dry regions, and Engler's {1914) paper can be regarded as classic in this field. On the basis of data obtained from geographical distribution and phylogenetic Âˇ 1 Professors G. Halffler and A. Hernandez Corzo kindly read the manuscript and their valuable suggestions are greatly appreciated. The elaboration of this paper was subsidized by the C.O.F.A.A. of the Institute Politecnico Nacional, Mexico.

J. RZEDOWSK I

TH E F LORA OF MEXICAN DRY REGIONS

afnnit ies of modern xerophytes, Engler (pp. 620- 621) dedu ced that plant formations ada pted to dry cli mate which included angiosperms in thei r composi tion, sho uld have existed since Cretaceous limes. Similar conclusions concerning An1erican arid regions were reached by Johnston (1940) and o ther authors; in contrast, Wiggins (1961 ), who invest igated the geographica l relat ionships of the flora of Baja Cali fo rn ia, arrived at quite an opposite conclusio.1, stating that probably "the aridity so pronounced at present is a phenomenon of more recent inception than is often thought". Wi th the aim of gaining some detailed insigh t into the problem, it was considered of interest to carry out an a nalysis of the geograph ic affinities shown by the fl ora of the arid parts of Mexico. · The flora of the Mexican dry regions can be regarded as relatively individualized: If in this account- the dry portions of southwestern Texas, southern New Mexico, southern Arizona and southern Cali fornia, which in fact are extensions of the Mexican dry regions, are included, a floristic assemblage can be obtained in which more than 50% of the species are restricted to its limits. The number of endemic, or practically endemic, genera amounts to 68 considering on ly woody plants (Rzedowski , 1962, p. 56) and p robably exceeds 100 if all flowering plants arc included. In this group the fo llowing genera can be mentioned : Caruegiea Holacantlw Jrlria Leucophyllwn Lophocereus l\1achaerocereus

Mortcmia 0/neya Pachycomws Sedcudes Simmondsia Viscainoa

Another group of genera has most of its species concentrated in the d.ry areas of th is cou ntry and many of them are important elements of the vegetation, but the dist ri bution areas of these genera go beyond the fixed limits. Here the following may be cited : Agave Encelia Eysenhardtia F/ourensia Heclttia

Mammillaria My1·tillocactus P<mheniu111 Yucca Zaluzania

On the fa mily level there are two endemisms: Fouquieriaceae and Crossosomataceae. A remarkable feature of the flora of the Mexican dry areas is the great diversity of life-forms, which were thoroughly classified and discussed by Shreve (1942, pp. 20020 I ; 1951, pp. 39-47), Miranda (1 955) and others. In this paper an attempt is made to analyze quantitativety the geographica l relationships of the flo ra of the arid zones of Mexico by means of comparisons carried out on three different levels: (/)between several localities within the limits of the arid zones of Mexico; (2) between arid zones in Mexico and in other parts of the world ;

(3) between a rid and non-arid zones in Mexico and in the western United States of America. In th is way it is intended to take into acco unt the most significant featu res of those geographica l relationships , keeping also in mind the possible origins of the flora. The co mpa risons were carried out by means of the formula proposed by P reston (1962):

T- ( ~. A o.e7

0.27

'- ) + n ·o.2;

where A and B arc the numbers of genera of each floristic list to be analyzed fo r similarity, and T is the theoretical total number of genera represented in both samples if A and B were members of the same flora. For the same theoretical conditions the number of genera common to A and B will be :

K = A -1- B-T and the coefficient of similarity between A and B:

cs =

100 L O/ __

if Lis the real nu mber of genera common to A and B.

Relationships between different arid zones of Mexico In order to analyze the mutual relationships between the floras of different parts of Mexico characterized by dry climate the following four areas were compared, for which flori5t ic lists are available : (I) the coast of the Gulf of California, in the states of Sonora and Baja California (Joh nsto n, 1924); (2) the northern half of the state of Chihua11Ua (LeSueur, 1945); (3) the Valley of San Luis Potosi, situated in the southwestern part of the state of San Luis Potosi (G. C. de Rzedowski, 1960); - (4) the Mezquital Valley, localized in the state of Hidalgo (Gonzalez Quintero, 1968). As shown in Fig. I, the first area represents the Sonoran1 arid region; the second area is situated at the northern extreme o f the Chihuahuan arid regi on; the third lies at the so uthern end of the same region; and the fourth coincides partially witlt the Hidalgan dry region of Miranda (1955), sit uated near the Chihuahuan region. ' ll must be stated that the choice of J ohnston' s (1924) paper to be used in the analysis, instead of the more complete and recent Flora of the Sonora11 Desert, published by Wiggins (1964) is due to the fact that the former includes a smaller number or genera and therefore constitutes a flo ristic sample more suitable for comparisons with other fl oristic lists used in this paper.

J. RZEDOWSKL

T il E FLORA OF M I' XICI\N DltY REG IONS

TJ\I! I.E I ( 'Ql: F FI('!ENTS ()F Sl ~l l l.ARITY Ul:i\V I:I· ~ n1E Fl .(m..1\S (}F FO UR I>U:H:IU:NT D ltY l'LIMA·n: A lt EAS IN MEXICO

··-··- ·-··-··-····· ··--·- ·- ·-··:·· -·· -----···

i.l'

/Jaja Cal({omia and Sonora

\ \

\._... ~

Baja California and Sonora (272 gen~ra) Ch ihuah ua (258 genera) San Luis Potosi ( 177 genera) Hidalgo (189 gener:t)

.....---··:"

'·-.

-- ----·

--- ......._,'

....

-- ·-':

-- - --- -------· --·r··.!.--

L - -- ---.. .

1::::

!.............,_.,_..........

~.- · ··

~·-.•:~-- i \

______ l

Fig. l. Principal arid zones of North America. I = Great Basin; 2 = Mohave; 3 = Sonoran; 4 = Chihuahuan; 5 = Valley of Mezquital; 6 = Valley of Tehuacan and Cuicathln. (Modified after Shreve, 1942)

C!Jiluwlwa

Sa11 Lui.r Potosi

llidalgo

51.9 %

45.4% 71.8%

41.0% 67.8%

51.9 % 45.4 % 41.0%

71.8 % 67.8%

87.0% 87.0%

Numbers of genera in paren theses represent the size of compared noristic samples.

Table I shows the existence of an ev ident floristic separation between the Sonoran region, on the one hand, and the Chihua huan and Hidalgan regions, on the other. Their coefficients of simi larity vary between 4 1 and 52%, while the values a mong remaining areas compared amount to no less Lhan 67%. Such separation becomes more manifest in light of the fact that these similarity values are Jo\'ver than the coefficient between the Sonora n dry region and the tropical deciduous forest of northwestern Mexico (see Table I I I), and some of the values arc si milar to the coefficient of similarity fo und between the Chihuahua n region and the Argentinian "monte" area (see Table II). Seemingly, Shreve (1942,-p.237) was the first botanist to recogn ize this phenomenon when he observed that "lists of the twelve most common and characteristic plants of the Sonoran and Chihuahuan deserts have only three species in common (Larrea, Fouquieria, Prosopis)". Rather than present geographical isolation (which is not complete in New Mexico and Arizona), the reasons for the floristic differences very probably reflect ecological differences, because the Sonoran region is evidently much warmer. Historical fac tors also may have played an important role, especially for the peninsula of Baja California. Rzedowski (I 966, pp.90-9 I) enumerates some examples of species common to the arid parts of San Luis Potosi and to the Sonoran arid zone, and gives also a list of gene.ra for the latter which are not found on the eastern side of the Sierra Mad re Occidental. Quite interesting is the high coefficient of similarity of the flora of the Valley of Mezquital, in the state of Hidalgo, in relation to the Chihuahuan region and especially to the Valley of San Luis Potosi. The geographic distance is not great, but the regions are separated by a somewhat less arid a rea and a disjunction seems to be evident in the distribution of a n umber of species, e.g., Ephedra aspera Euphorbia antisyphi!itica Flouremia cemua Fouquieria campann/ata

Fraxinus greggii Koeberlinia spinosa Larrea tridell/a/a Leucophyllum ambiguum

Gonzalez Quintero (1968, pp.47-48) insists also o n the similarity of these two regions and gives a long list of shrubs common to both.

J. R ZEDOWSK I

THE FLORA OF MEXICAN DRY R EG IONS

While the flora of the Mczquital Valley, and also that of a small dry zone in Queretaro, diiTers little from the flora of the Chihuahuan region, the arid Valley of Tehuac{m and Cuicatl{m , located. about 250 km to the southeast, in the boundaries of the states of Puebla, Oaxaca and Veracruz, shows a marked contrast. According to Smith (1965, pp.l33-142) of 253 species collected in the latter zone, 74 ( = 29.1 %) arc endemic to it, a very high figure for such a small area. Unfortunately Smith does not provide a li st of those species and therefore it is impossible to eva luate at present the relationships of the flora of the Valley of Tehuaci111 with those of other arid zones of Mexico by means of coefficients of similari ty. In general terms, however, it is evident that the valley has floristic <iffinities with the arid regions of central and northern Mexico, although there exists also a marked influence of tropical elements, especially of those characteristic of the Pacific slope of Mexico. The relative floristic independence of individual arid zones of Mexico can also be shown by means of endemisms on a generic level. No complete data are available, but according to Rzedowski ( I 962, p. 56}there are 2 I genera of woody plants restricted to the Sonoran region, 8 of which are only known from Baja California; those of the Chihuahuan region are 16. The Mezquital Valley in Hidalgo apparently has no endem ic genera, but that of Tehuacan, Puebla, seems to have several as exemplified by Oaxacania, Pring/eoclrloa, Setclrcllantlws and Solisia.

Relationships with other arid zones of the world Relative differences and si milarities of the flora of the arid regions of Mexico compared to those in other parts of the world are shown in Table JL The lists of LeSueur (1945) and Johnston (1924) are used as the basis for comparison, representing the Chillllalllla n and Sonora n arid zones. Data extracted from the following publications are also used for comparison: (/) G raham's (1 937) paper on the vegetation of a part of the G reat Basin area, states of Utah and Colorado, U.S.A. T ABLE II COEFFICIENTS OF SIMILARITY BETWEEN TH E FLORAS OF SOME DRY CLIMAT E AREAS IN MEXICO AND I N OTHER PARTS OF TH E WORLD

Great Basiu Coastal Peru (U.S.A.) (210 geuera) ( 142 genera) Chihuahua (258 genera) Baja California a nd Sonora (272 genera)

"Moure" Sahara Ceutral region (376 genera) Australia Argeutina (153 genera) ( 163 geuera)

26.5 %

33.3%

42.1 %

19.0 %

20.0%

24.9%

31.0 %

37.0%

19.9%

23.3%

Numbers of genera in parentheses indicate the size of compared floristic samples.

(2) Ferrey.Fa's (1 953) pa per, which gives a list of plants of thc arid zone of coa~ta l Peru. (3) Morello's (!958) paper, contai ning a list of species of the dry pre-andine "JHonte" region of Argent ina. (4) Ozenda's (1958) book, bei ng a fl ora of central ami northern Sahara. {5) Cleland\ (1936) paper, which includes a list of species of the dry regi on of central Australia. The values of coefficients of similarity given in Table II show that the flora of Mexican arid zones has relatively slight relationships with those of the Old World arid zones. This is a rather well-known fac t and the common genera arc main ly taxa of cosmopoli tan or pantropical distribution, as e.g., Acacia Aristida Artemisia Caesa/pinia CliSSia

Dodonaea Jatropha

Lycium Maytenw· Mimosa Randia Sa/.,ia Solmwnr Suaetla

Much more interest ing, however, is the existence of a small but signi ficant group of genera common and more or less restricted to several dry regions of the world, among which the following CQn be listed: A triplex Cressa Ephedra Frankenia Menodora

Nicotiana Notholaeua 0/igomeris Peganum Thamnosma

Also noteworthy is the fact that the similarity between Mexico and Aust ralia is somewhat greater than that between Mexico and northern Africa. Although the diffe rences have no statistical significance, the fac t is interesting, because oft he remote-· ness of the A ustralian continent and the pronounced individuality of its flora. l f the figu res are n ot the result of an error due to deficiencies of sampling techniques, the explanation of this greater than expected similarity may lie perhaps in the relative coi ncidence of ecological conditions between Mexico and Australia. Similarity of ecological conditions seems also to be more importnnt than distance in the case of floras of American dry zones. Thus, the pre-andine region known as "monte" in Argentina has a maximum of floristic similarity with Mexico, surp assing the coefficients of the less distant zone of coastal Peru, an area of scarce rainfa U, but, in contrast with other dry regions, a high atmospheric humidity and frequent fogs and a plant cove• that is mainly herbaceous. Both South American areas, however, have greater coefficients of similarity than the G reat Basin region of the western United States, situated in the continuous belt of arid zones in North America (Fig. l ). The pronounced differences between the flora of the latter and that of Mexico have their origin, at least in part, in the low winter temperatures prevailing in the Great Basin,

J. RZEDOWSK I

THE C:LORA OF M EXICAN DRY REG IONS

which create unfavourable cond itions for most plants ol" tropical anl nities. T he foll owi~g common genera show thi s rather unexpectedly weak aiTinity between both florets: Abronill Caulamlws Eurotia

N.I'IJU'JWCh•a

MttlllctJfhri.\·

Stretllmllhellti

Returning to southern atnnitics, besides the presence of a number of neotropical lineages, many authors (Gray and Hooker, 1880, pp.57-60; Bray, 1898, 1900; Standley, 1916; Kruger, 1934; Johnston, 1940, and others) called attention to signifi- . cant floristic similarities between South and North American arid zones. Such circumstance is particularly remarkable not only because of the great distance between both areas. but also in view of the presence of an extensive barrier of humid and semihumid areas interposed between them, where, seemingly, many of the xerophilous elements common to Mexico and South America do not ex ist. This type of discon tinous distribution can be found, for instance, in the genera: Allenro/fea Caste/a Coldenia Com/alia Ence/ia Flourensia

Fl'anseria Cutierrezia Huj/i•umseggia Larrea Purlierill Salll'italill

Atamisquea emarginata Bouteloua barbata Celtis spinosa Cercidium praecox Cryptantlw albida Enneapogon desvauxii

Koeberlinia spinosa L eptoch/oa dubio Namaundulatum Notho/aena aurea Sc/eropogon brevifolius Vallesia g!abra

and in the species:

(/)The basin of the Mayo River in so uthern Sonora; tropical deciduous fo res t ("short-tree forest"), the composi tion of which was st udied by Gentry (1942). (2) The states of Jalisco, Colima and some adjacent areas ("N ueva Galicia"); tropical decid uous fo rest, described in the paper of Rzcdo'>I'Ski and MeVaugh ( 1966). (J) The middle basin of the Papaloapan River; trop ica l rain forest, studied by G(\mez Pompa ct al. ( 1964). (4) The Sierra Madre Occic_lcntal, in the state of Durango; pine forest, investigated by Maysilles (1954): {5) The Valley of Mexico; fir forest, described by Madri_gal Sanchez (I 967). (6) The coastal mountains of central Califor nia; oak forest, studied by Harry (1940)at Coal Mine Ridge. "(7) The Cascade Mountains, extending from California to Washington; various coniferous forests, the flora of which was listed by Cooke (1962). TABLE II[ COEF FICIENTS OF SIMILARITY llETWEEN THE FLORAS Of SOME DRY CLIMAT E AND NON-DRY CLIMATE AREAS OF MEXICO AND WESTERN UNITED STATES

-· -~·--- ·

.....

- -- - --

Besides, a very significant number of closely re!ated species can be found in different genera, being separated by the same disjunction.

Relationships with zones of non-arid climate A comparison between the composition of the flora of the Mexican dry regions and those of other regions and plant communities of the same country and of western United States, is also of interest. For this purpose the seven areas and vegetation types given below were selected, for which floristic lists are available, in order to analyze their similarities with the lists already cited of LeSueur (1945) fo r Chihuahua, and of Johnston (1924) for Sonora and Baja California. No areas with semi-arid climate adjacent to those characterized by arid climate, were selected, on the assumption that both show significant mutual floristic influence.

Chihuahua (258 genera) Baja California and Sonora (272 genera)

---

----· - ·S. Sonora Jalisco aud Oaxaca Durango Valley of_ Coast. Casc. M t. , trap. dec. Colima twp. rain pine {or. Calif Co /if, Ore., Mexico for. trop. dec. fur. fo r. (278 gen.) fir for. oak for. Wash. ( 303 geu.) ( 145 gen.) ( 278 gen.) (66 geu.) ( 129 gen.} COlli/. for. (425 /{1!11.) ·~-~--

47. 3 ~{

18.3 %

13.6%

53.3 %

28.6%

23.7/~

- - --

42.4 %

24. 1%

·--

28.4 %

13.6%

1 9.7~/.

13.6 ~~

11.9%

16.5%

-~---

Numbers of genera in parentheses indicate the size of compared floristic samples.

Interpreting the coefficients of Table Ili it can especially be noted that the flora of the Mexican arid zones presents stronger affinities to the south than to the north, because the similarity coefficients with oak and coniferous forests of California scarcely reach 20%- This fact partially reflects the relatively poor participation of Holarctic elements in the studied flora; among the few representatives of such affinity the fo llowing can be mentioned : Fraxiuas Juniperus Populus

Quercus Salix

the majority of which occupy rather marginal or particularly favoured situations within the arid regions. Similarly, in spite of the close geographical proximity, there are relatively few

J. REZDOWSKI

characterist ic Californian genera represented in the Mexica n arid zones; in this gro up may be cited: Ceanot/ws C/wenacti.\· £riogom11n

Esch.rcholzia Gilio Peustemon

The similarity relat ionships of the fl ora of arid zo nes, as compa red with those of different non-arid zones of Mexico, a re evidently affected by si milarities and diflerenccs in temperat ure condi tion s. T h us, the war mer Sonoran arid zone su rpasses the Chihuahuan in affinities with tropical forests; on the contrary, the C hihua hua n zone has in its fl ora more elements co mmon with coniferous forests of the mountains of Mexico. The values of simila rity coefficients wi th the tropica l deciduo us forest of sout hern Sonora arid wi th the pine forest in Durango a rc proportionally very high, due probably to the influence of a close vicinity of the sampli ng si tes, but essentially do no t interfere wi th the above mentioned quanti tative relat ionships. If cosmopolitan, pan tropical and other widely ranging ge nera are discarded, the significan t components of the a ffini ty to the flora of no n-arid regions of Mexieo can be divided into two principal groups: (/) neotropica l clements, and (2) elements of restricted distrib utio n to Mexico and adjacent regions. The neotropical influence can be exempli fied by: Aloysia Antigonon Be/operone Bursera Cirltarexylum Gouinia

Guaiacum Hwtis Lysiloma Opwlli(l Pedikmtlms Tilla/1(/.fia

f: !

THE FLORA OF MEXIC AN DRY REG IONS

do minate evidently over the northern ones, and the tclationships wi th regio ns as close as the no n-arid parts of Cali fornia and the Great Basi n of the western U nited States, a rc relati vely scarce. (2) If very widely distributed genera arc elim inated from t he analysi s of this fl ora, among the remaining compo nents- on the same taxo nomic level- two geograph ic clements dominate: a neotropical one, and one rest ricted to Mex ico and adj acent areas. Tn the l a!!~r, genera el'ldemic to the arid zones of the co untry play an important ro le. Wit h a d ecreasing degree of imp o rtance are the Ho larctic fl ora (especially thro ugh elements of western North America), the flo ra .of a rid zones in other continents, and the flora of the South American mo untains. (3) T he preceding facts indicate that the bulk o f the fl o ra of Mex ican dry regions o.riginated independently fro m t hat of th e neighbouring arid zone of the Great Basin in the United States. Mexican xerophytes evidently derived from ancestors ofneotropieal or generally tropical affin ity, while most of their counterparts in western United States descend from p re-adapti ve form s of n orthern origi n or d istribution. (4) The flora of the Sonoran arid region has a larger p art icipation o f tropical elements than the Chi huahuan and that circumstance determines, at least in part, significant differences between those regions. The magnitude of these differences, in fact, can be compared with th ose existing between the Chihuiihuan zone and the preand ine "monte" arid region of A rgentina. T he remarkable similarity between the flora of the Mezq uital Valley, in H idalgo, and that of t he Chihuahuan region makes more evident the contrasting significance of flori stic individuality of t he ar id zone of · Tehuacan and Cu icatlan Valley, in Pu ebla and Oaxaca. Such ind ividua lity can be interpreted as ind icative of a long period of isolation of the T ehuac!111-C uicatlan d ry area from the remaining dry regions of Mexico .

A mong genera with d ist rib ution restricted to Mexico and neighbo uring regions the follo wing can be mentioned : Carloll'rightia Cyrtocarpa Erythea Eucnide Florestina

Gymnosperma Hilaria Hintonia No/ina Xamhucephalum

Finally, there exists a less important group of Mexican-South American mountain genera, represented by a few species in the arid zones, as for instance: Baccltaris Bricke/lia Gochnatia

Monnina Viguiera Zinnia

Conclusions

(1) Within the geographical affinities of t he flora of Mexican arid zones the southern

References Barry, M . L., 1940. A floristic and ecologic st udy of Coal Mine Ridge. Comrib. Dudley H erb., 3: 1-40. Bray, W. L., 1898. On the relation of the flora of Ihe Lower Sonoran zone in North America to the flora of the arid zones of Chili a nd Argentina. Bot. Gaz., 26: 121- 147. Bray, W. L., 1900. The relation$ of the North American flora to that of South America. Science New Ser., 12:712-716. Cleland, J. B., 1936. T he botan ical features between Oodnadatta and Ernabella in the Musgrave · ra nges, with a locality list of plants from the no rthwest of South Australia iden tified by J. M. Black, A.L.S. Tratts. R. Soc. South Aust., 40 :11 4-125. Cooke, W. B., 1962. On the flora of the Cascade Mountains. Wasmarm J ., Bioi., 20: 1-67. E ngler, A ., I 914. Ober Herk unft, Alter und Verbreitung cxtremer xerothcrmer Pfla nzen. Sitzungsber. K . Preuss. Akad. Wiss., 1914: 564-{;21. Ferreyra H., R ., 1953. Comunidades vegetales de algunas lomas costaneras del Peru. Est. Exp. Agr. La Molina, Bal., 53 :88 pp. Gen try, H. S., 1942. A s tud y of the flora and vegatetion of the va lley of the Rio Mayo, Sonora. Cam. Inst. Wash., Pub!., 527:1- 328.

J. RZEDOWSK I

Gomez Pompa, A .. Hcrn{tndcz l';tllares, L. and Sousa S<inchcz. M., 1964. Estuclio fotoccologico de Ia cucnc:1 intcrmcdia del Rio Papaloapan. In: Comribtrciotres a/ Esttrclio Emlu~:ico de /a.1· Zonas Ctilido-ltrimeda., de Mt!xico- ln.rt. Nacl. llll'est. For., Mexico, Ptrbl. Esf'ec., 3, pp.37- 90. Gonzalez Quintero, L., 1968. Tipo.1· de Ve~:etaciun del Valle de Mt•zqtrital, H~:o. Departamento de l'rehistoria, lnstituto Nacional de Antropologia e l-listoria, Mexico, D.F., 49 pp. Graham, E. H., 1937. llotanical studies in the Uinta Basin of Utah and Colorado. Anu. Cam. Mus., 26: 1-432. Gray, A. und Hooker, J .D., 1880. The vegetution of the Rocky Mountain region, and a comparison with that of other parts of the world . Bull. U.S. Ceo/. Geogr. Snn•., 6:1 - 77. Johnston, I. M., 1924. Expedition of the Cali(ornia Acadeniy of Sciences to the Gulf of Califo rnia in 1921 - The botany (the vascula r plants). Proc. Calif Amd. Sci. 4 Ser., 12:95 1- 1218. Johnston, I. M., 1940. The fioristic significance of shrubs common to No rth and Sout h American deserts. J. A mold Arborctum,21 :356-363. · Krliger, 0., 1934. Die Gmmineenf/om im nordamerikanischen wul siidameriktmi:>c!Jen Tmdcengebiet. Thesis Phil. Fak. Friedrich Wilhelms-Univ., Berlin, 63 pp. LeSueur, H. , 1945. The ecology of the vegetation of Chihuahua, Mexico, north of parallel 28. Unil•. Texa.1· Pub/., 452 1: 92 pp. M<tdrigal Sanchez, X., 1967. Contribuci6n a l conocimiento de Ia ccologia de los bosqucs de oyamcl (Abies religiosa (H.B.K.) Schl. et Cham.) en cl Y<tlle de Mexico. lust. Nne/. l111·est. For., Mexico, Bo/. Tee., 18: 94 pp. Maysilles, J. H., 1954. Floral Relationships of the Pine Forests of West em Durttugo, Mexico. Thesis, Univ. M ich., Ann Arbor, Mich., 165 pp. M iranda, F., 1955. Forrnas de vida vegetalcs y cl problema de Ia dclimit<lcion de las zonas aridas de Mexico. In: Mesas Redout/as Sabre Problemas de las Zonas Aridasde Mexico. Ediciones Jnstituto Mexicano Recursos Naturales Renovables, Mexico, D.F., pp.85- 119. Morello, J., 1958. La provincia fitogeografica del monte. Opera Lilloana, 2:1-155. Ozenda, P., 1958. Flore du Saham Septemriona/ et Central. C.N. R.S., Paris, 486 pp. Preston, F. W., 1962. The canonical distribution of commonness and rarity. Ecology, 43: 185- 215; 410-431. Rzedowski, G. C. de, 1960. Notas sobre Ia nora y Ia vcgctacion del cstaclo de Sun Luis Potosi, 7. Vegetaci6n del Valle de San Luis Potosi. Acta Cieut. Potos., 4:5-11 8. Rzedowski, J., 1962. Contribucioncs a Ia fitogeografia floristica e hist6rica de Mexico, I. Algunas consideraciones acerca del clcmcnto endernico en Ia flora mexicana. Bol. Soc. Bot. Mex., 27 : 52-65. Rzedowski, J., 1966. Vegetaci6n del cstado de San Luis Potosi. Ac·ta Cient. Potos., 5:5-291. Rzcdowski, J. and MeVaugh, R., 1966. La vegetacion de Nueva Galicia. Coutrib. Uuil'. Mich. Herb., 9:1 - 123. Shreve, F., 1942. The desert vegetation of North America. Bot. Rev., 8:195- 246. Shreve, F., 1951. Vegetation of the Sonoran Desert. Cam.lust. Was/1., Pub/., 591: 1- 192. Smith, C. E., J r., 1965. Flora Tehuacan Valley. Fie/diana Bot., 4:107-143. Standley, P. C., 1916. Comparative notes o n the floras of New Mexico and Argentina. J. Wash. A cad. Sci., 6:236- 244. Wiggins, !. L., 1961. The o rigins and relationships of the land flora. In: The Biogeography of Baja Califomia and Adjacent Seas, 3. Terrestrial and Fresh-water Biotas. Syst. Zoo/., 9:148- 165. Wiggins, !. L., 1964. Flora of the So no ran Desert. In: F. Shreve and I. L. Wiggins, Vegetation ond Flora of the Sonoron Desert. Stanford Univ. Press. Stanford, Calif., pp.l89-1740.

! C!Japter4

Ecology of the Vegetation of Veracruz1 ARTURO G6MEZ-POMPA

Departmemo de Botdnica, lnstituto de Biologia,

Unil'crsida~/

Nacionul Autunoma de Mexico

Su01mary A summary is presented of recent studies and unpublished data from current investigations on the ecology and vegetation of Veracruz, Mexico. The types of plant communities are defi ned and their occurrence related to prevailing ecological facto rs such as cl imate (temperatu re, precipitation), altitude, soil types, and the effect of man on the natural vegetation. Introduction Veracruz IS the most varied of all the states of Mexico. This variat ion resulted out of its latitudinal extent, its complex topography and the variety of its soil types. The state of Veracruz is located on the Gulf of Mexico and extends from 17°10' to 22°20' N. It occu pies 62,820 sq. km being a strip of land approximately 800 km in length by 50- 150 km in width.

Physical conditions Topography

Veracruz is composed mainly of lowland areas; the altitude of most of the state is less than 300m (Fig.!). However, the state contai ns an important branch of the mountain system of central Mexico, which is a part of the Sierra Madre del Este and also·part of the Cintur6n Neovolcanico that crosses the country. These mountains are also very important because they include the highest peak in Mexico, Mt. Orizaba ' Flora de Veracruz, Contribution no.4. A joint program of the l nstituto de Biologia of the Universidad Nacional Aut6noma de Mexico and the Arnold Arboretum and Gray Herbarium of H arvard University, to prepare an ecological floristic study of the state of Veracruz, Mexico. (See Anales Ins/. Bioi. Univ. Nac. Auton Mex., 41, Ser. Bot., I: l -2). The author is indebted to .Bernice G. Schubert and Lorin I. Nevling for their valuable suggestions to the manuscript. N icolas Aguilera critically reviewed the part of the text concerned wit h soils. Margarita Soto made valuable comments on t he climate of Veracruz. This paper was partially supported by a grant from the National Science F oundation {GB-20267X).

A. G6MEZ-I'OMPA 98'

ECOLOGY OF THE VEG ETATION OF VERACRUZ 96'

(Citlaltcpetl), which reaches an altitude of 5,747 m. Another important mountain system is the Sierra de los Tuxtlas composed or a series of volcanic cones extending to ca. I,700 m in attitude. At the sout hern end of the state there are a few unexplored branches oft he Sierra Mad re del Sur which have an altitude of I ,000 m. The remainder of the state is more o r less flat with the exception of a small sierra located ncar the 21st parallel and reach ing 700 m.in altitude (Sierra de Tantima).

State of Veracruz Alt i metric mop

22'

(alti t udes above sea level)

Clima/e

{From U SAF nav i gation chart)

22'

20'

-/--!--

cotre de

(J\

-:0 -:0

-j-

20 '

b-:0

16'

--1-

(I'

1000

(I'

r 18'

300 500 1000 sca l e

100

200 KM

96'

Fig.l. Altitudinal map of Veracruz.

.94'

As a result of topographical variations a nd latit ude, climatic factors are rather variable in Veracruz and explain, in part, many of the distribu tion patterns of the vegetation types and of their component species. The climates of Veracruz have been st udied by Garcia ( 1970). H er system of climate classification is extremely useful from the biological point of view, because it takes into consideration those factors to which vegetation responds, such as amount o f rainfall during the dry season, and temperature variation between the coldest and warmest months. As f will use her work in climatic references to the vegetation types, a map of the climates is included (Fig.2). On the following pages I shall discuss some oft he climatic fac tors with special e~np h asis on their importance to vegetation d istribution. Temperature. This fac tor has an important effect on the vegetation in relation to its variation in an altitudinal gradient. Most of the state is warm with average temperatures of more than I8Â°C (Fig.3). T he average values as such do not mean much in understand ing species d istribution; th e temperature values that are more important arc the extremes, especially the minimu m extreme temperatures, because they serve as filters for the distribution of species. The most important factor to note is that there is only a small gradient in average monthly extreme minimum temperatures, which are lower at h igher latitudes. _Previously latitude has not been considered ecologically significant at lower altitudes in the tropics, but it seems that in the state of Veracruz it is of great importance. If we study the absol ute minimum temperatures the problem becomes clearer (Fig.4) : there are very low temperatures in the northern latitudes in comparison with the south, and the vegetatio n corresponds to this temperature gradient. The ranges of many species in Veracruz seem to be determined by winter temperatures, because other facto rs (mainly soils and precipitation) seem not to excede t he limits of tolerance of most of the species. This problem is also interesting because it opens the possibility of doing some experimen tal studies on the effect of low temperatures on populations of extreme tropical lowland species, in relation to the adaptation of other species to this same facto r. I have not yet found evidence of a direct relationship between the distribution of plant species and extreme high temperatures in Veracruz. High temperatures seem to be more closely related to dryness and are important for this reason.

ECOLOGY OF THE VEGETATION OF VERACRUZ

A. G6MEZ-POMPA 96'

h·cczing temperat ures (below O"C) a rc frequen t in the mountains and absent in the lowla nds (Fig.S) with the exception o r Tantoyuca in the northern portion of the sta te (Soto, 1969).

96'

St ate of Vera c ruz Types of c I i mote 22'

!S.§j

AwO

ffiillll

AW2

~A I (m)

g~:;~

~Aw l

~Am -ET H EFH mcwlo Cwlb

(ill)~:~~ El ~~\~;" lillHll t1f~<'~) ~\<;.))gr;~) [ill

22'

~:~~~ ~::~~~

20'

Rainfall. Rainfall is the most important ecol o g i ~.:a l factor allccting the vegetation of the state at any given altitude. There are two aspects to be considered : o ne is the total amount o f rainfall, and the other is its dislribulion t hroughou t the yea r. If we look at the patterns of lola! raii!fcdl ( Fig.6), it is evident that t here are great extremes : fro m less than 500 mm in the tem perate desert to more t han 4,000 mm on the lower slopes of the sierras. The ma in reason for such a distributi on is the di1ection of the humid trade winds of the northeast that change in direction and in ascent on contact with the special topography of the continen t. The consequent cooling produces heavy p recipitation on the windward side and scarce precipitation on th e other side. Th is is the cau~e of the upper deser ts and the lowland dry areas. The northern dry zone is produced by the Sierra de T a m aulipas; the semi-arid zone near the port of Veracr uz is produced by the Sierra de Chiconquiaco just below the 20th parallel ; a nd a semi-arid zone on its southwest side is produced by the Sierra-de los Tuxtlas. The other aspect of rainfall is the distribulion of rain throughout the year. ln most parts of the state there are two well-marked seasons: the rainy season and the dry season. In the middle of the rainy season there is a temporary decrease in precipi-

20'

18'

16'

sca 50

100

200KM

94'

Fig.2. The climates of Veracruz. (After Garcia, 1970.) Garcia, in her description used the Jist of symbols given on p. 77.

Hum id dinwte~i: A = hoi humid C = Iemperate E =cold A(C) or (A)C = hot temperale ETH = cold at high alii tudes EFH = very cold or wilh ice all the year, al high alii tudes m = summer rains with monsoon influence Am(f) =summer rains wilh monsoon influence, winter rains higher than 10.2 % Cf(m) = precipitation of the dries! mOnlh higher Ihan 40 mm, with the percentage of winter rains higher than 18% w = summer rains regime w0 = summer rains regime with P/Tiower than 43.2 w1 = summer rains regime with PIT between 43.2 and 55.3 w, = summer rains regime wilh P/Thigher Ihan 55.3 a= warm summer, with the average temperature of the warmest monlh above 22•c b = long and cool summer, with the average Iemperature of the warmest month above 22•c c = short and cool summer, with the average temperature of the warmest month lower than 22°C and less than four months with the average temperature above 1o•c Dry clima/es BW =very dry BS, = dry k = temperate with warm summer, average annual temperature between 12• and t s•c, temperature of the warmest m onth above I8°C k' = temperate with cool summer, average annual temperature between n• and t s •c, temperature of the wa nnest month lower than ts•c

.,.

A. G6MEZ-POM I' A

78 99'

96'

97 '

22"+

St ate of Verac r uz Ther mi c zones

Avera ge an n ual temperature (•C )

(ill]

very hot mor e tha n 26•

~ ~ ~

hot

IIllllll

sem i cold

•

s~m i

22'- 2!!' ho t

21"

CO l r.:c,..-<:cn 00< OcutQ O• 0 Btttcto o• 1 Boca Scxtt<OSIQ 0 18 COPwii'IU 020 Cd Alemdn

09 :! Pt1ttot, los

09> Rinclll'\o:Jo 096 Rrncon Poeheco

Oll

090 I 06 10 9 110

OIJI'tm;o, RUM:hO

0 31 :iron t il, Lo

18 ' - 22 '

h mp e ratt 12' - 18°

5'- 12' between - 2 ' a nd s•

very cold l e ss than - 2•

~O"C

~ ''"'·: <r<

0<0 Hrda 14jOi rl ldn 0 41 ~k90, [I 0'3 kylocro dl lo

Ill l.lo~•

0<0 h lo Lobos OH lt leto, Lo

052

I. C

Noutl0

19"

G.JtrO!'ft 1' lOII\CIO

.....

0~1

ROdri~ue) Cloto San Mr~ u c l

Son N.colo' SCfllfOQO dt to Ptfio

Sont!ll90

TU~~ IlO

112 So n bo~Uo, hlo dt 114 So!edud dt Ootllodo 117 Toncocl'lojlo

118 Ton1111a

0 5 0 JOIIrj)On 051 .H,Y, COIIOfllO

16 '

00. Polfr.or, El

087 Pdft.AQ 080 Poi'K)IIIlo 09 1 J\)1o Reo

021 CO\omotoopoll 0)0 CltCI..alctolapan

Qj!)

co ld o r

08 4 O: IUoolllo

Cotou..tl~t~

I ZI Tt ccluno 124 TtM(:oot

o>• Loudtopcn O>G l o-.o Fino 0 57 No~.,os

126 Teuchodcan

0>8 Mcntos. los 059 Mont.o Fabio Allonw~o OGO t.IOIO ~ UII'IOMS 061 M alo T.nohiO 063 N orliloet Cit kl Torte OOG rllt'IOI1U61l 070 Morwo S.. 012 tll)tzc•Of190 082 Otohllon

129 Tfototafpon 130 Tt<llu (.Oyatl Ill

1~7

r,, ,o

IZB

fiAO)O$

Bto~~Cc.

,.....

ll2 Tres ZQfoles ll5 Ve9CJdt A!otcwre

ve-.,t.o..o

Vdlo h!.C COI'dtl

...

ConOn.-t~

Z090titld11

1<7 hmpoal

09 3 Ororonnt

.. 0

IJO' t

19'

IB"

19"

16'

·-Isc o le

.,.,

f7•

100 96'

Fig.3. Thermic zones of Veracruz. (After Garcia, 1970.)

2.00Km .

97'

...

+ .,.

...

Fig.4. Minimum extreme temperatures measured from 1921 to 1910 in stations lower than 300 m ; there are two very distinct areas: in the northern portion with temperatures close to o• and in the south with temperatures around 1o•c.

A. GOMEZ-I'OMPA 98"

ECOLOGY OF H IE VEGETATION OF VERACRUZ

96" 97"

St ate of Veracruz

State of Veracruz

22" ~

Annua l ra i nfal l (mm)

Num ber o f d ays per year with frost

22"

20"

less t han 800

fZZ1

800-1000

1000-1200

1200-1500

1500-~0 00

2000-2500

2500-3000

EZ:8

3000-4000

more than 4000

-!-

-+ 18°

20"

-+ 0

Son A.TUXtla

18"

19"

18"

sca

17"

100 96°

18"

-1-

200KM ~4·

Fig. 5. Frosts in Veracruz. (After Soto, 1969.)

s c a 1t 50

tation (see F ig.l4) causing a few days of dry and warmer weather called "canicula" (Mosifio and Garcia, 1966). Its ecological importance has not yet been evaluated. From the ecological viewpoint the most important season is the dry season, which is also the colder season. T he amount of rain during the dry season varies greatly, and on this variation depends the type of vegetation in the region : evergreen,

97"

100

96"

200KM

95"

Fig.6. Rainfall in Veracruz. (After Garcia, 1970.)

r I

A. G6MEZ-POMPA

ECOLOGY O F TH E VEGETATI ON OF V ERACRUZ

35' Stat io n Ah.a liln

State of Veracruz P l uv iomet r ic regimen Ro i n1oll

symbo l s

r2g i m~ n

summor

le.ss t ha n 5 •1.

UTID

E§l

5-10.2 • /o

Feb M ar: Apr May Jun Jul.

~2~-

AUQ Scp Oct No,. Dec

-9

Coo tepee

9 .6

COrdoba

5.3

Coscomatepec

6.8

Cuaut o tolopan

• .6

Dob ladcro

Je ss than 18 •J.

20'

9 .9

Coot za coa lc o

Durango, Rancho

3.9

Isla l o bos

Jo loc ingo

7.7

Jaltipon

6.9

Mi sontlo

15.4

Mot z.orongo Nautlo

4.9 13 3

O ri za ba

OtatiU6n

4.9

O zuluomo

6.3

Pa nuco

4.8

Papontfa

18'

scc fc: 0

100

20 0 KM 95°

A~~t~~f

•l-4~

18 n3

~~J~

16J

_JZ9__ _

600

2610

1~.

9__

2'))0

10_ -

9.7

Perote

6.7

Po t r ero

5.4

Rinconada

4.0

Sn. Andres Tuxtl o

4.6

Sn. Juan Evangelist a

5.4

So ledad de Doblado

3.6

Tanto yuca

6.8

Tlocotalpan

5.6

Tux pan

8 .5

Venustiano Co.ron.za

5.6

Ve raCt:"UZ

3.0

....

. 6 . ..•9

_,3_ 12

__7_. 12

:!972

-~ -

1~~--

!0_ . 17- 17_ -'~!...-

17 20 24 ------ . --- 25 '2'66

211

1 6~

28 6

22 e;e

13 1&ooS

6 __ 2'~"

19, 1

Jll\32'

-~~__!I_ __,:__!7__ _,~ ___2_ -~--~-4 90

679

..021

r-2~-- ....!.'?__!!,_, -·~- --~ -- 12 n• o

m e

124e

.B.

n4e

1109

--~1__ ~

..,

<4!i l

1) 0 1

332

JOO

1(1,1 5

]~- 13

1'1)()<)

.2..

2•c.2

12'0 )

(iJ6

1 7<4 ~

.• .??L

~~·ct>

37'll

1 21~~

4 · · -~- ~ - ~305 7

3216

__ 1~0__

5 .,2~

3823

1)02

~ .~9... -?Q.. .~-~~.. l97

~~B?

"'"'

,~ _ _!Z_ _~

tW 2

2035~

1.0__ 12 - ~

18'

C hicon tepec

~ 10 .2-18°/o ~

_]~

r o ins

IIDfl

un i formly

9.1

Jon

Soco Sochiapa

•!.winh: r

distributc:d

or..~~i~~,.

_?_6_

.?6_ _2_9 __"{/._ p _

21 _ 21 _2 4__ 21_ _2 4

9 16

-47 ~

2_6

1 0!)) 4

?9~91 56

20 -~Q. . ._3_2_ 21_ J:n

)70

4 9'-

227

1617

8 7fi

(il4

1Ui99

3_0__1~-- _2() _'!;l_ . .?:'

370

182 )

712

11? __1_8_ _ _29 ___15 1279

1148

I()?)

2658

.?.?. __I9l.__

1970

94'

Fig.7. Rainfall regimen in Veracruz. (After Garcia, 1970.)

· Fig.8. Distribution of dry days (above) in different stations of Veracruz. These figures can be compared with the figures of rainfall for each month (below).

A. G6MEZ-POMPA

ECOLOG Y OF THE VEGETATION OF VERACRUZ

semi-evergreen, or deciduous. The rain during thi s period is not brought by the trade wind s but by polar air masses (called "nortes") that bring rain, and in some areas, low temperatures. Garcia (1970) has made a classilication of these winter rains using the percentage of winter rains in relation to total rainfall (Fig.7). This value is of i;11portancc because there is a close relation between the total amount and the amount at the 98'

Stat e o f

Veracruz Number of

dry season. However, the value that is of direct interest is the total number of dry days throughout the year and the distribution or these days in each month (Fig..&). This value can be used t~ explain the presence of certain vegetation types in "wrong" places.

Fog. Another form of precipitation that is seldom taken into account is fog. In large areas in the mountains of Veracruz, fog is cha1acteristic, and the name "cloud forest" is appropriate for these areas. The average number of days wi th fog is a good measure and is indicated in Fig.9. It is evident that these areas have higher humidity and less illumination, two factors that can explain their characteri stic flora.

96'

22'

Snow. Snow rarely occurs in Veracruz except on the highest peaks. It has been reported from several stations in the mountains above 1,200 m alti tude. Even though snow is not regular in altitudes just above 1,200 m, its occasional presence may explain the absence or various species and genera in these localities. Among the most important staiions reported with snow (Soto, 1969) arc Atzalan, Jalacingo, Orizaba, and Perote.

days per

y e ar with f og

22'

Soils 20 '

-../.... I

18'

20'

-/_ I

16'

scale

100

96'

Fig.9.

200KM

94'

Number of days with fog in Veracruz. (After Soto, 1969.)

In contrast with the knowledge of climates, the so ils of Veracruz are very poorly known and a soil map of Veracruz is still needed. However, there are some isolated ~o i l studies helpful toward an understanding of the soil variation in the state. Soils are produced by the interaction of climate, organisms, rocks, and also by topography and time. W e know the climate ofVeracruz and we have also some information about the rocks, but we know very little about the action of organisms in soil formation. The great diversity of soils in Veracruz comes in part from the diversity of parent rock materials available, and as this is combined with a great diversity of climates, the result is a great number of different edaphic habitats. For example, basaltic lava flows can be found in very different.climates of Veracruz from t he very humid, warm lowlands of Catemaco where a tall evergreen selva develops, to the drier warm lowlands north of Martinez de Ia Torre where a lowland oak forest grows, to the temperate regions above Jalapa where pine forests are found in lava flows. In all three instances the parent rocks are very sim ilar, and the climate determines the difference in vegetation. The geology of Veracruz is well known and some distribution patterns of species in similar climates follow the geological patterns as will be discussed later. In any particular climate, the soils determine the changes in the distribution patterns of species and therefore of the vegetation types. I shall discuss what is known of Veracruz soils in relation to each of the vegetation types. The soils of Veracruz can be divided roughly into the following Great Groups: red and yellow lateritic soils, ando soils (yellow and brown), vertisols, lithosols (incl. regosols), calcimorphic, saline, alluvial, and swamp soils.

TABLE I ANALYSIS OF A SOIL PROFILE1 1N A PINE FOREST

Depth

Horizon

( Pinus har/ll'egii)

Colour

(em)

when dry

ON TH E SO UTHW ESTERN SLOPE OF T HE PICO DE OR IZAI3A IDENTI FIED AS AN ANDO SOIL (CRYANDEPT) •

Appar. density

Relat. density

Sand

Silt

Clay

(%)

(% )

(%)

Texwre

(1:2.5)

when wet

(3,740 M ALTITUDE); THE SOIL WAS

Total C.fo. Org. C/N C.E.C. AlloN (% ) mauer (mequiv.f phane ( %) (%) 100 g)

-- -~-------------·~ · ~

0-5

All

10YR 5/ 1 grey

IOYR 2/ 1 black

1.20

2.24

58.0

35.1

6.9

sandy loam

6.2

0.253

3.57

8.12

21.0

xxxx

5-15

Al2

!OYR S/1 grey

10YR 2/ 1 black

1.31

2.32

61.3

31.9

6.8

sandy loam

6.3

0.184

2.45

5.61

19.0

xxxxx

15-25

A12

lOYR 5/ 1 grey

IOYR 2/ 1 black

1.30

2.31

60.7

32.5

6.8

sandy loam

6.2

0.172

2.55

5.84 ·

19.1

xxxx

25-35

A13

lOYR S/ 1 grey

IOYR 2/ 1 black

1.22

2.22

57.3

36.3

6.4

sandy loam

6.2

0.226

3.06

7.01

25. 1

xxxx

35-45

Alb!

10YR 5/ 1 grey

10YR 2/ 1 black

1.23

2.25

63.6

27.7

8.7

sandy loam

6.2

0.203

2.74

6.26

22.3

xxxx

45-55

Alb!

IOYR S/ 1 · grey

I OYR 2/ 1 black

1.15

2.22

6 1.0

28.3

10.7

sandy loam

6.2

0.242

3.24

7.42

25.1

xxxx

55-65

Alb!

lOYR 5/ l grey

10YR 2/ 1 black

!.II

2.23

57.2

32.1

10.7

sandy loam

6.2

0.235

3.36

7.70

27.2

xxxx

65-15

A1b1

10YR 5/ l grey

IOYR 2/ 1 black

l.l 4

2.29

6.1.7

29.9

8.4

sandy loam

6.2

0.206

2.94

6.75

25.1

xxxx

75-85

A lb!

lOYR 5/ 1 grey

lOYR 2/ 1 black

1.04

2.27

54.4

36.1

9.5

sandy loam

6.2

0.177

2.72

6.24

23.3

xxxx

85-95

A l b2

IOYR S/ 1 grey

JOYR 2!1 black

1.1 3

2.25

57.4

33 .5

9 .1

sandy loam

6.3

0.156

2.45

5.61

~::!. .'2

xxxx

95- 105

Alb2

!OYR 5/ 1 grey

IOYR 2/1 black

1.18

2.36

55.6

35.7

8.7

sandy loam

6.3

0. 145

2.21

5.06

21 .8

xxxx

105- 11 5

A 1b2

IOYR5/ l grey

IOYR 2/ l ,black

1.1 8

2.40

55.6

37.7

6.7

sandy loam

6.3

0.127

1.98

4.52

23.5

xxxx

11 5-1 25

A l b2

JOY R 5/ 1 grey

lOYR 2/1 black

1.39

2.44

63.0

30.3

6.7

sandy loam

6.3

0.091

1.42

3.26

17.2

xxxx

125-135

A lb2

!OYR 5/l grey

IOYR 2.5/ 1 black

1.35

2.54

61.6

3 1.9

6.5

sandy loam

6.3

0.086

1.21

2.76

17.1

xxxX

JOYR 5/ 1 grey

!OYR 2.5/ 1 black

1.1 7

IOYR 5/ 1 grey

IOYR 2.5/ 1 black

1.18

?' Cl

0 3: 1;-l

0"" 3: ;

~ ·

135-145 145-155 155-165 165-175

A lb3 Al b3 Alb3

1.29

2.5Y 5/ 2 greyish brown

IOYR 3/ 1 very dark grey

1.30

185-195

!OYR 5/2 !OYR 7/2 light grey greyish brown

195-205

A l b4

IOYR 6/ 2 light grey

!OYR 7/2 IOYR 5/ 2 ligh t grey gt·eyish brown

!OYR4/ I dark g rey

38.7

8 .7

sandy loam

6.3

0.166

2.06

4.70

27.4-

XXxX

2.37

60.8

29.0

I 0.2

sandy loam

6.3

0. 171 2.32

5.30

27.2

xxxx

2.43

63.3

29.7

7.0

sandy loam

6.3

0. 136

1.69

3.86

23.3

xxxx

-n

:I:

1.40

2.49

2.52

57.1

59.8

36.1

44.7

4 .8

5.5

sandy loam

6.4

0.095 . 1.21

0.046 0.36

2. 78

0.83

18.8

I 1.2

xxxx

2) ~

xxxx

~ 0 z 0

-n

1.36

2.52

44.1

50.7

5.2

silty loam

6.3

O.Q35

0.25

0.49

·10

10.4

xxxx

< m

1.30

2.46

4 5.6

47.5

6.9

sandy lo am

6.4

0.087

0.88

2.02

17.5

xxxx

;;o

- - - -- ------- - 1After J o h nson

-< -l

IOYR 2.5/ 1 black

52.6

8 r Cl

!OYR 5/ 1 grey

175-185

2.35

~- ,

> (")

c:: N

(1970)

A. G6M EZ-POMPA

ECOLOGY OF T HE VEGETATION OF VERACRUZ

Red and ye/fow laterilic soils. These soils are fo und basically in the warm or semiwarm areas and have many variations. They arc characterized by their red or yellow color and the low con tent in silica compou~1ds in the upper horizons (A), which on the ot her hand, arc rich in sesq uioxides of aluminum and iron (Mohr a nd Van Ba ren, 1954; sec Table V).

leaching of salts fro m the surround ing mountains that accumulate in a closed wate rshed and, in thi s very dry region, prod uce a lw.lophytic envi ronment. As in ot her salt deserts, the vegetation is unique. T he othe r sal ine soils are those of the coastal areas, which also support a unique flo ra (sec f-"ig.34).

A11do soils (yellow and brown). The ando soils have been found mainly in cold areas of Veracruz (Johnson, 1970). They are fo und also in temperate regions of Veracruz and even in lowland areas as in the Los Tuxtlas region (Whiteside, 1960). These soils are derived from volcanic ash and are very rich, supporting a permanent agricultu re with two or three crops a year (Tables I and X). Planosols and vertisols. These soils, about which very little is known, are fou nd in restricted localities in the state on very flat topography. Some unique vegetation types develop in them, such as some palm stands and low selvas. In many cases these soils have a paler horizon that has been called pseudogley, caused by a high water table (glcysols). Many of them arc inundated in the rainy season and dry very drastically on the upper surface in the dry season (Fig.29,30). Âˇ Litlrosols (incl. regosols). These soils a re a complex group ; the only common factor among them is that there are no soil horizons developed, only the parent rock in different stages of decompo5ition. T he two most important rock soils are the volcanic and the limestone soils. The volcanic soils are distributed widely in the state. They sometimes sustain a very rich flora because of the many microenvironments pt ed uced among the rocks. The limestones are also fou nd in several localities and in different thermic regimen. The karstic topography of many limestone areas is caused by the high precipitation that dissolves the limestones irregularly giving them their characteri stic rough topography. The true soils are very thin and located between the rocks. They are rich in calcium compounds, which have an important influence on the floristic composition (Gomez-Pompa et al., I964b). The rock soils prod uce a drier environment locally because they have high drainage and poor water retention in comparison to deep soils in the same macroclimate. Calcimorphic soils. Calcimorphic soils are soils derived from calcareous rocks and are, therefo re, rich in calcium compounds. When the limestone is broken and decomposed, the soil developing has large amounts of calcium compounds. These salts and others accumulate in the upper horizons in soils of the dry regions. On the other hand, in time, calcimorphic soils of wet regions can evolve in different directions in relation to the climate (Aguilera, 1958). Saline soils. Saline soils are known from one locality on the border with the state of Puebla between Perote and Alchichica (see Fig.33). This soil is produced by the

Alluvial soils. These soils may be of very diverse origins, the only factor common to them being located nea r nowing water. They do not have well-defined horizons, and their other characteristics may vary wit h the climate or with the parent rock. These soils support a vegetation that di ffers remarkably from the vegetation of neighbouring areas in the same macroclimate. Swamp soils. Swampy soils in Veracruz are not very common and may be divided into two groups: the mangrove swamp soils (see Fig.37) and the inland swamp soils. On ly a few profiles have been studied in relation to vegetation studies (Vazquez, 1971 ).

Vegetatio n The vegetation of Veracruz is a result of the combination of all the environme ntal variables that have been discussed, in additi on to many ot hers of which we know very little, such as the paleobotanical history of the area, the effect of man on the vegetation, and the ani mal/plant interactions . By this I mean that the amount of available in formation permits some correlations be tween similar ecological requirements of species, thus allowi ng us to make a classification of the vegetation of the area. At the same time, the lack of information on many other ecological variables expla ins the absence of correlation and the inconsistencies which make such a classification seem very incomplete. I will restrict my di scussion to the primary vegetat ion, which is the vegetation that appears to be the most stable one in the area, where there are no signs of probable replacement by other vegetation types in the near fu ture. Many of these types are disappearing quite rapidly because of h uman activities, and secondary vt'getation is fast becoming the dominant vegetation in the ~t ate. The classification to be fo llowed is the one proposed by Miranda and Hernandez X. (1 963), with slight modifications to incorporate some intermed iate types found in the state. Some of the names will be in Spanis h only because translation of them can lead to errors (Gomez-Pompa, 1967). With in each type only the most characteristic species will be mentioned. A few quadrats that have been studied elm ing the ecological survey of the Gulf Coast region of Mexico (Anonymous, 1960- 1969; Gomez-Pompa et al., J964a) will be used to illustrate the structure of the vegetation and to typify it. T he data that will be incl uded are a synthesis of available material. The details for each region will be omitted as much as possible because these are, or will, be discussed in regional studies n ow in progress and planned to include the whole state.

A. G6M EZ-POMI>A 0

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ECOLOGY OF THE VEG ETATION OF VERACRUZ

Since vegetation is the-resu lt or the com bi ned acti on of nu merous environme ntal factors on the s pecies available in an area, there arc numerous very different correlation patterns. The most obvi ous one is t h e tempera t ure/vegetation relationship in the mountai n zonat io n, but we should not be misled by t his as oth er facto rs such as fog and rainfall also change with altitude, and it i ~ no t easy to separate them. Therefo re, it is necessary to emphasize t hat each vegetation type has to be treated separately and st udied independe ntly. There arc some vegetation types found only in a ce rtain restricted cli mate, and o thers fou nd in a wide va riety of climates. There are ty pes of vegetation restricted to certain soil types wh ile others live in many difl'ercnt soil types. An attempt to show some of the correla tions of vegetation types with climate that I recognize for Veracruz is illustrated in Fig. I0. As there is some confusion in co nnection with the hiera rchical arrangeme nt of vegetation and the terminology used by di fTercnt a uthors, I will use only the term "vegetat ion type" for a group of wild plants ph ysiognomically recognizable as a unit, and more or less stable (primary in our sense). Within each vegetation type, several comm unities or associations exist, and l define them as grottps of plants in a restricted area having si milar ecological require ments and a similar macroclimate. The problems and theoretical discussions that are the basis of this poi nt of v iew have been di ~cus sed elsewhet e (Gomez-Po mpa, 1966, 1967). In recent time there have been s_eve ral studies related to the vegetation of Veracruz prepared by the ecological survey p rogram of the lowlands of the Gulf of M exico undertaken by the "Comision de Dioscorea s of t he National Institute o f Forestry Research o f Mexico" (Anonymo us, 1960-1969 ; Gomez-Po mpa et al. , 1964a). I n addition to the data gathered-a nd still being med, the Comision has produced, directly or ind irectly, several papers including data on the vegetation of Veracruz (GomezPompa et al., 1964b; Gomez-Po mpa, 1966; Pen nington and Sarukh!m, 1968 ; Sousa, 1968; Toledo, 1969; Chiang, 1970; Leon and Gomez-Po mpa, 1970 ; Cuanalo and Aguilar, 1970). Another project that has promoted several recent studies of vegeta tion is the Flora of Veracruz program (Gomez-P ompa and Nevling, 1970) of wh ich the work presented in th is paper is a part. Several o ther vegetation papers have been produced as a part of th is program (So to, 1969; Lot, 197 1; Vazquez, 1971; Ramos, 1971). Additional studies related to the vegetation of Veracruz which should be mentioned are the general paper on the classificat ion o f t he vegetation of Mexico by Miranda and Hernandez X. (1963) in which Veracruz is ment ioned in their treatment of the types. T he work of M iranda and Sharp ( 1950) o n the clo ud forests includes a description of many sites in Vetacr uz. A paper by Williams ( 1939) on the t rees of the southern portion of the state is also important. A fe w additional papers were consulted ; t hey will be mentioned in the description of the types related to them. In order to help explain the physical rela tionships among the different vegetation types, a series of diagramma tic vege tation profiles will be presented from different geographic regions of the state.

....

TABLE II KEY FOR THE VEGETATION TYPES OF VERACRUZ

-------,---

Vegetation dominated by trees (woody plants of more than 4 min height) B.

A very dense tree community with several dominant tree species; frequen tly with severalty pes of climbing plants (Selva)

Dominant trees without spines D.

Evergreen E.

Dominant trees of more than 30 m of height

(4) High e11ergreeu selra

EE. Dominant trees Jess than 30m of height (usually less than 10m)

(7) L ow evergreen selra

DD . Trees with deciduous leaves F.

s: rn

Trees higher than 15m G.

t;'l

Trees of more than 25 m

{ 5) High semi·e1·ergreen sell-a

GO. Trees shorter . .

{6) lvfedium semi·e1·ergreen seh•a

FF. Trees lower than 15 m H.

? 0·

More than 75% of the trees have deciduous leaves.

3 :!:; ~

(9) Lo"· deciduous selra

H H . Less than 50% of the trees have deciduous leaves

(8) Loll' Sl!llli·e1·ergreeu seha

CC. Many dominant trees with spines .

( 10) Loll' thom selra

BB. A more open tree community, with few dominant tree species (usually one or two) and few climbing plants (forest) I. Trees branched

J. More than 50% of the trees deciduous . . . . . . . . . • . . . . ( 3) Deciduous forest

JJ. More than 75% of the trees evergreen K.

Land tree con1numitics

L. With broad leaves

• . . . . . . . . (2) Broad-leaved f01·est

LL. Wit h needle or scale leaves -'1

Needle leaved .

( l) Need/e-/ea1·ed forest

MM. Scale leaves . .

{I) Scaltt-leaved forest

KK. Swamp tree communities

( 19) Mangrove forests

II. Unbranched . . .

I II) Palm ;·tands

AA. Vegetation dominated by shrubs or herbaceous pla nts N.

Land communities

In coastal regions with marine influence . . ( 2 1) Coastal dune., 1·egetation m

00. Not in coastal regions P.

Mainly dominated by herbaceous plants

In lowland warm areas . . . . . ( 12) Sa1·anna

-< 0

QQ. In upland temperate and cold areas

"l1

-1

In saline soils . . . . .

( 14) Saline gr·as.rland

RR. Not in saline soils

S. In cold areas above 4,000 m . . . . . . . . {20) Paramo 1·egewtiou SS. In temperate areas below 4,000 m . . . . . . . ( 13) Temperate grassland

PP. Not dominated by·grasses T.

Great ab'undance of plants with rosette leaves. . . . . . . ( 15) Nolina·Heclrtia-Agaredesert

TT. Abundance of thorn shrubs {16) Thorn scrub

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NN. Communities partially or totally in water part of the year or all the year . . . . . . . . . ( 17,18) Swamp 11egetolion t)'J)es or (22) Aquatic 11egetation types 10

A. G6MEZ-POMPA

Fon'!lts The term fores t incl udes those vegetati on types that arc arborea l and whose dominant species arc few, frequently only one or two. These occu r mainly in the temperate a nd cool mountain regions where the humidity is enough to sustain a tree com munity. In these regions the low winter temperat tJres are the most important ecological fll ter responsible fo r the poor diversity of tree species in contrast with the selvas in the lowlands. Forests in the lowlands arc found only in areas in which some extreme edaphic conditions have become important limit ing factors; the most widespread tree communi ties in these lowla nds are the seh·as.

(I ) Needle-/eared forests and scale-/em·ed foresrs. In compariso n wi th other states of Mexico, t he pine forests of Veracruz are relatively poor and limited in extent, but almost all the main climatic subtypes recognized (Gomez-Pompa, 1965) are present in the state. The highest and coolest pine forest in the state is the one formed by Pinus hart· IVegii growing within the li mits of the paramo vegetation in t l~e highest mountains, at an altitude of between 3,000-4,000 m or more (Balls, 1939; Johnson, 1970). The flora of this forest is not well known and the only reliable ecological info rmation available is that produced by Johnson. The climate of these communities is unknown beca t;se there is no meteorological sta tion at this altitude, but by extrapolation from other mou ntai ns at the same latitude, the average mean temperatu re must be in the range of 4-11 <c. A soil profi le known at this altitude may be..seen in Table I. Some of the common plan ts reported (Johnson, I 970) fro m the area are the following: Dominant species Pinus lrart wegii Lind!. Other species Abies t•e/igiosa (HBK.) Schlecht. et Cham. Alchemil/a vulcanica Schlecht. e t Cham. Arenaria bryoides Willd. Arenaria serpens H BK. Castilleja sp. Cerastium orithales Schlecht. Ceraslium vulcanicum Schlecht. Cnicusjorul/ensis HBK. Eryngium proteafiorum Delar. Ha/enia nudicaulis Mart. et Gal.

Halenia paucijlora Hems!. Lupinus elegans HBK. Lupinus moll/anus H BK. Lupinus vagina/lis Cham. et Schlecht. Oxylobusarbutifolius(HB K.) A. Gray Pentstemon gemianoides (HBK .) D on Pitws montezumae Lam b. Potentilia richardii Lchm. Stenanthium frigidum K unth Stipa ichu (Ruiz et Pav.) Kunth

In the more protected areas in the higher altitudes near the tree line, a forest of Abies religiosa can be found. This fo rest has been reported from the Mt. Orizaba (Johnson, 1970) and a similar one probably exists in the Cofre de Perote. There are no data

ECOLOG Y OF T HE VEGETA TlON OF VERACRUZ

available on the floristic compositio n of these forests, but we may expect them to be not very diiTcrcnt from neighbouri ng p ine forests. At lower altitudes, between 2,000 a nd 3,000 m, there are pine forests in several areas of the slate. T hese tempera te pine forests are the most common type in Mexico, and most of our species of pi ne have been descri bed from them. In these areas t he pine forests arc mixed with oak forests forming local ecological mosaics possibly due to local humidity gradien ts, soil type, or human activities. The cl imate in these areas is mainly temperate and humid (C) and may contain different subtypes. Some climatic data from a station located in this vegetation are shown in Fig. II.

Latitude 18•43' Longitude 97"19' Altit u de 1500.00m A C U LTZ ING O Aver age annual t empera t ure 17.4•c To t al annual romfoll 723.7mm

700

E ~

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5c 0

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200

:;:

100

Fig. II. Climatograph of a station in a pine forest region.

The soils of these pine forests are n ot known. I have fou nd only one soi l profile description from forests of Pinus pseudostrobus above Or izaba and it probably corresponds to an ando-sol. T his forest is interesting becau~e it is located within the limits of a warmer vegetation, and many species of the lowlands come to form a part of it. The following species have been reported from this community (Chiang, 1970) :

A. G6MEZ-POM!> A

ECOLOGY OF THE VEGETATION OP VERACRUZ

Domhuuu :,pecie.v

Pinus pscudost robus Lind!. Other species Alnus ar;:uta (SchlcchL) Spach. A nmdinella deppeana Nccs Calea integrijiJ/ia (DC.) Hems!. Caleamanicata (Schlecht.) Bent h. ct Hook. Calea urtidfolia (Mill.) DC. Crnsea ca/oceplwla DC. Diphysa f/oribwrda Pcyr. Eupawrium asclrenbomiamm1 Schauer. Eupatorium morifoliwn Mill. Gnap/w/ium braclryplemm DC. Quer·cus ctmdicam· Nee Quercus xa/apcnsis Humb. La;:ascea lrelianthifo/ia HBK. Lantana lrhpida H BK.

LitJpia hypo/cia Briq. Lit.wa glaucescen,· H13K. Pam tlresi.1· .rerrulata (Sw.) Mcz Pteridium aquilimn11 (L.) Kuhn Rapanea myricoides (Schlecht.) Ltmdell Rubn>· adenotriclws Cham. ct Schlecht. Saurctuiu pedrmculata Hook. Senecio gmndifo /ius Less. Senecio ,,·draJ]ireri Schultz Bip. Smilax .rpi11osaMill. So/anumtorvum Sw. Temstroemia syll'atica Schlecht. ct Cham. Vemonia deppeana Less.

Several pine fo rests have develo ped on the lava beds above Jalapa. The largest seems which the follo wing species are found:

w be one of Pinus teocote in

Dominant species

Pinus teocote Cham. ct Schlecht.

Pinus pseudostrobus Lind!. Othe1· species

A;:m·e xaltl/u:nsis Roezl. Arenaria /ycopodiodes Willd. Bacdwri>' COI((erta H 0 K. Biden.l"triplinen•ia HI3K. Castilleja longibracteata Mart. et G al. Cheilmrthes microphy/la Sw. Comus disci/lora DC. Comusexcelsa HBK. Holenia bre••icomis(HBK .) Don

Lytlrmm ocinifoliwn (DC.) Koehne Ma/axis soulei L. 0. Williams Monoc/wetum jloribundum (Schlecht.) Naud. Oxa/i.> comicu/ota L. Oxalis decaphylla HBK. Quercu.l' caucliams Nee Rumex acetosel/a L. Relbwriw11 hypoca111ium Hems!.

Fig.l 2. Forest of Pinus cembroides in the region of Perote (Veracruz) with No/ina fXII'I'if/om. (Photo C. Ranios.)

TEZIUTLAN - TLAPACOYAN - NAUTLA

A large area of temperate pine forest is found near Huayacocotla on the border of the state of H idalgo; this is dominated by Pinus teocote, and the fo llowing species have been found in it: Domina/11 species Pinus rudis End!.

Pinns teocote Schlecht. et Cham. Other species

Alchemil/a pectiuara HBK. A/mrs arguta (Schlecht.) Spach. Arbutus glandulosa Mart. et Gal. Ascyrum hypericoides Linn. Baccharis conferta HBK. Brunella vulgaris Greene Chimaphi/a maculata (L.) Pursh. Cor11us disci/lora DC. Comus excelsa HBK. Erythraea macra11tha Hook. et Arn. Galium UIICinu/atum DC.

Leucothoe mexicana (Hems!.) Swall. Lophosoria quadripimwta (Gmel.) C. Chri. Pinguicula cauda/a Schlecht. Pteridium aquilimrm (L.) Kuhn Quercus casta11ea Nee Quercus candicans Nee Quercus crassifolia Humb. Quercus mexicana Humb. Ranuncu/us dichotomus Moe. et Sesse Spilanthes americana (L.f.) Hier. Temstroemia sy/vatica Schlecht. et Cham.

LIOUIDAMBAR FOREST

HICH $ (MI ·EYERG RUN

tilLVA

OAK FOREST

MAifCitOv.E S WA M P

Fig.I3. Vegetation profile Teziutlan- Naulla showing the boundaries of the forest of Pinus strobus var.

chiapensis.

A. G6M EZ-POM PA

ECOLOGY OF T HE VEGET ATION OF VERACRUZ

In the contact zone between the subhumid temperate and the temperate arid vegetation, on t he border wit h the state of Pucbla ncar Perote (Ramos, 1971), sma ll populations of Pinus cembroides a re found at 2,500 m (Fig. l2). The floristic composition of this community will be discussed also wit h the arid vegetation because its fl oristic composition is similar to other types, except in the more protected areas in which this species grows with Quercus micropily/a and Sophora secwuliflora which have similar

Dominant species PinuJ strobus L. var. chiapensis M:trtincz Other species Bro.l"inwm a/icastrum Sw. Humpeu ilrtcgerrima Schlecht. Bnmcllia mexicmw Standi. Quercus exec/sa Licbm. Cymhea costaricensis (Kuhn) Domin Sauvagesia erecta L. Ncp!telea mexicana (Schlechi. ct Cham.) Tryon

Jn the T uxtlas region on the eastern slopes of the volcano Santa Marta, a forest of

Loti t ude Long itude Al t it ude · PUENTE

Pinus oocarpa is found at an altitude as low as 500 m, mixing at this altitude with some

19'56' 97'12' 510.00m

species from the lowlands and some from the deciduous fo rest above, such as the fo llowing:

HENR IQUEZ

Domi11a11t JiJecies

Average annual t em perature 22.9°C Total annual rainfall 2266.5 mm

Piuus oocarpa Schiede Otlrer species 700 600

Alibcrtia ed1tlis (L. Rich.) A. Rich. Bulbostylispapillosa Kukcnth. Byrsonima crassifolia (L.) DC. Clethra macrophylla Mart. et Gal. Crotonnit e11s Sw. Croton repens Schlecht. Leucothoe mexico11o (Hems!.) Swall.

Liquidambar macmplryllo Ocrst. Mosquitoxylonjamaicense Krug. et Urban Myrica cerifera L. Paspa/um pectinatum Nccs Pa.<palum plicatulum Michx. .Saurauia serrata DC. Zamia loddigesii Miq .

T his forest grows in red lateritic soils with low organic content. It also grows at higher altitudes on the same volcano, but no floristic study has yet been undertaken. Other species of pine that have been found in Veracruz are: Pinus ayacalwite Ehrenberg Pi11us leioplrylla Schlecht. et Cham.

M A

Fig.J4. Climatograph of a station very close to the area where Pilws strobus var. chiapensis occurs.

ecological requirements. This community grows on very thin calcimorphic soils. Also in this area small patches of a Scale-leaf Forest dominated by Juniperus deppeana are found living also in this transitional region. In t he region of Tlapacoyan a forest of Pinus strobus var. chiapensis develops in a very restricted area at a n altitude of 500 m (Fig.13). T his species grows in the contact area of the high selvas with the deciduou~ forests having a mixture of species from those vegetation types. The climate of the region can be extrapolated from the data of the nearest town (Fig.14). The species that have been reported from this forest (Miranda and Sharp, 1950) are the following:

Piuus montezumoe Lamb. Pinus paflila Schlecht. et Cham.

(2) Broad-leal'ed forests. These forests a re found ma inly in the temperate regions of the state, although a few are found in the warm lowlands. The most important are the oak forests which have an enormous ecological diversity. More than forty species are known to occur in Veracruz, many-·of them important components of many forests. Other types of broad-leaved forests have been reported from the state, but m ost of t hem are SJllall and may be lumped with other vegetation types. The oak forests of Veracruz may be divided into two main climatic groups: the· temperate and the warm. T he temperate oak forests are to be found in the same general area as the pine forests in this climate, forming a vegetational mosaic. T he two forests share a great number of species and, in some cases, may be treated better as pine-oak forests rather tha n as separate, distinct types. The evergreen oak forests of higher altitudes have not been studied from the ecological point of view. The oak forests from the warm areas are better known, and a more integrated scheme can be presented. These forests occupy large parts of the lowla·nd areas in the

100

A. G6MEZ-I'OM PA

ECOLOGY Or: TH E VEGETATIO N OF VERACRUZ

siHtc, and as a group may be considered a relict vegetation type. In recent geological ti mes, during the last glacial ion, the temperature decreased and certain groups of plants from the temperate mountainous regions invaded parts of the lowlands and mixed with more tropical taxa. During these times many taxa probably were eliminated by the lower temperatu res, pr ovid ing ecological niches that were then occupied by tempera te elemen ts such as Quercus, Piuus, Podocarpus, Myrica, and Cletlrra. When the area warmed, many of these groups retreated to the cooler mountains or died in the competition with better ada pted tropical groups that returned or spread from their restricted areas (warmer protected places). Bu t some of the temperate elemen ts found niches where tropical species did not thrive, such as drier places and poorly drained soils. Here the temperate plants have survived up to now. There is no direct evidence that thi s is true, and the whole idea is derived from indirect evidence of distribution patterns (Miranda, 1959 ; Gomez-Pompa, 1966; Toledo, 1969, and others) as discussed elsewhere in this paper. The oak forests of the lowland areas in Veracruz are found in very different cl imates, from drier areas in the northern part of the state to very wet po.rtions of the south. In the region of Poza Rica, a fores t of Quercus oleoides is found on Java flows. This fores t is up to 25m tal l and has a rich herbaceous flora. The following species have been found in this area :

.-i M

'li

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C"!

101

Dominant species Quercus oleo ides Cham. et Schlecht. Other species Alcltomea latifolia Sw. Byrsonima cra.nifalia (L.) DC. Dendropanax arboreus (L.) Decnc et Planch. Ficus maxima P. Mill.

Sapium/atcrijforum Hems!. Tapirira macrophylla Lundell ZinOII'iewia htlegerrima Turcz.

In the Misantla region (Gomez-Pom pa, 1966) several quadrats were studied under different soil conditions. The soil analysis for an oak forest in this region is in Table III. Sovonno ot C r-r~CMtio cujctc w ith Curatetlo

americana

"'"' c!,c!, "'

c!,

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Sem i-deciduous sel ves

Selva of Glnoria ttudlfloro

Ook t ore

stot

Oucrcvs

otcoidcs

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l torestof Ook ISelvaofiSelvo of Trrml. Broslmumwith Quercus ,olio nio

E 0

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olcoidts omazo.

Fig. l5. Vegetation profile from Los Naranjos, Veracruz- Temazcal, Oaxaca. The tropical lowland oak forests grow side by side with other vegetation types. Each one occupies a different soil type. (After G6mez-P ompa et al., l964b).

Âˇ

A. G6MEZ-POMPA

102

ECOLOGY OF THE VEG ETATION OF VERACRUZ

103

Another tropica l oak forest is fE*Ifld- in the area of sout hern Veracruz on the bo rder with the sta te o f Oaxaca. This forest grows in red and yellow lateritic so ils with high clay content a nd poor internal drainage. As the to pography is undulating, there is a micro topographical factor giving a catena of soil and vegetation, from t he upper parts covered ma inly by oak forests to the lower parts covered by different selvas (Fig. l 5). The following species have been fou nd in this fo rest : Dominant species Quercus oleoitb Cham. ct Schlecht. Otltcr species Byrsonima crmwfoHa (L.) DC. Cocco/oba borbadcnsis Jacq. Conostegia xalapensis(Donpl.) D. Don Cnratclla americana L. Genipa cantlo H 0 K .

Ptcridimn aqui/imm1 (L.) Ku hn Quercus spp. Waltlteria brel'ipesTurcz. Xylosmaf/exuosum (H BK.) Hcmsl. Zuekmia guidonia (Sw.) B ritton ct Milsp.

(3) Deciduous forests. The deciduous fo rests occur in Veracruz only in the temperate Latitude 19' 9' Longitude 95'57' Altitude 1344.00m HUATUSCO Average annual t emperature 15.7Â°C Total annual rainfall 1745.0mm

Fig.17. A Liquidambar macrophyl/a forest in Huatusco, Veracruz.

F ig. 16. Climatograph of a station located within the region of the Liquidambar-Quercus deciduous forests.

and more h umid areas of the mountai ns. One of the most in teresting ecological characteristics of these areas is the frequency of fogs. For this reason they have been called "cloud forests". I n Fig. l6 a select ion of climatic data from a station located in the deciduo us forest region is given. Such forests are usually found a t altitudes between I ,000 and 2,000 m (Fig.l7). In the Sierra de Chiconquiaco, so uth of Misantla, the deciduous forests are dominated mainly by Liquidambar macrophylla mixed with several species of Quercus. These fo rests develop in yellowish soils derived from volcanic rocks. The fl ora is very rich, and there seem to be no sharp differences in the vegetation patterns in this zone. The variatio n in floristic composition is a gradual one following topographic and humidity gradients (Gomez-Po mpa, 1966). This fo rest may be very tall, up to 40 m in height. One of its interesting characteristics, in contrast to other deciduous forests in northern latitudes, is that many species here remain evergreen. The name refers to the dominant species, which have deciduous leaves.

104

A. G6M EZ-PO MPA

ECOL OGY OF THE VEGET ATION OF VERAC RUZ

Other .1pecies

l n this sierr.a the fo llowing species have been no ted:

Al/itroa mexiccma D. E. Stone Carpinuscarolinimw Walt. Eur:eniamexicmw Stcud . Guarea cltidton C. DC. lngalatibmctettiCt Harms 0/medie//a betsdtlericma (Go cpp.) Locscncr Palicuurea galeottiana M arL Phoebe gent lei (Lund .) Stan di. ct Stcycrm. Pithccellobium ••ulctmortntt Sta ndi. ct Steycnn.

Domina/11 .\7Jecie.\·

Liquidombor mocruphylla Oerst.

Querc·us ajfiui>· Schwidw. Other species

Ardisia hyaliua Lundell Be/aria gltmca Hum b. ct Bon pl. Bn mellia mexicana Sta ndi. Caln Jtnmthes karll'inskyana Berg. Carpinus caroliniana Walt. Centradenia sa/ici[olia Brandeg. Cestrum endlicheri Miers Cestrum fasciculattmt(Schlccht.) M iers Clethra macrophyl/a Mart. el Gal. Cleyera .rermlata C hoisy Coccocypselum hirsulum Bartl. Conostegia Mborea (Schlecht.) Schauer Cyatheaful••a (Mart. el Gal.) F ee Deppen purpusii Standi. Diospyros riojae G6mez-Pompa Eugenia tnmcif/ora (Schlecht. ct Cham.) Berg. Fagus mexictma Martinez Heliconia bihai L. Heliconia sc/riedeana Klotzsch et Gkc. flex ••omitoria A it. Juglans pyriformis liebm. Klugia aznrea Sch lecht. Loasa triph)•lla Fuss. Lycopodium cenmum L. Magnolia scltiedeana Schlecht. Marsdenia macrophylla (Humb. et Bonpl.) Fourn.

105

Meliosma alba (Schlech t.) Walp. Nephelea mexicmta !Schlecht. et Ch;un.) Tryon Oreopcmax /iebnwmti M arclw I Peperomia deppeana Sch lecht. et Cham. Peperomia glabella (Sw.) A. Die tr. Peperomia obuwfolia (L.) A. Dietr. Perrottetia longistylis Rose Persea cinera.1·cens Blake Phoebe acuminatissima Lu nd . Podocmpas matuclai Lund. Pnmus tetradenia Koehne Quercusocolet((o/ia Licbm. Riclwrclia scabra L. Rondeletia cttpitellata Hems!. Sah•ia amarissima Ort. Sambucus mexicana Pres! Saurauia ••illosa DC. Solanumlanrifaliwu M iII. Temstroemia sylwt!ica Schlecht. ct C ham. Tetmnema mexicammt Bent h. Tillandsia po/yswchya L. Toumefortia petiolaris DC. Trium[elfa dumetorw11 Schlec ht. Verbena carolina L. Viburmwttiliaefolium (Ocrst.) Hems!. Xylosma jfexuosum ( I-I BK.) Hems I. Weinmmmia pinna/a L.

Pmmts brachybotrya Zucc. Quercuscm-rttgata I l ook. Quercnr pilcwius T rcl. . Sluaneasp. Tulau11w mexictuw (DC.) Don Tricftilia g/abra L. T11111in ia alL pcmiculata Vent. Xylomw quicltense Don. Smi th

A very intriguing questio n concerns the decid uo us character of many of the component species of the forests beca use in these lat itudes the winter is not severe eno ugh to explain t hc_"adva ntage" of the decid uous habit. Al so the humidity is high all year, so a d ry season is not a selective factor. It may be that the deciduous habit is a relict characteristic retained only beca use there has not been strong competition with other tree species. Perha ps the explanation is to be fo und in the winter temperatures, which, although not very low, might explain the absence of t he more tropical tree species very sensitive to tempera ture. On the other hand, the very high humidity and poor light might explain the lack of success o f ot her temperate elements from the forests above. In the Cerro de San Cristobal near Orizaba at an altitude of approximately 1,200 m (Mira nda and Sharp, 1950) a deciduous fo rest of Engelhardia mexicana was found in the central part of the steep nor-t heastern slopes where very deep soils occur. The followi ng species were reported : Dominant opecie>· Eugelltardia mexicana Stan di. Other opecies

In the area near 1-Iuatusco, a decid uous forest was sam pled and a quadrat made {Chiang, 1970) to show its structure. Other species fou nd in th is forest are:

Cletltra quercifolia Lind!. Comus florida L . Deppea grandi/fora Schlecht. Ho/fmannia orizabettsis Standi.

Dominant species

Liquidambm· ntacr·opltylla Oerst. Ostrya virginiana (Mill.) Willd. Rondeletia bourgaei Standi. Senecio grandifolius Less.

Liquidambar macropltyl/a Oerst.

Se/ms

Other species Dussia mexicana (Standi.) Harms Psycho!ria ar. tricltoloma Mart. et Gal. Quercus spp.

Styrax glabrescens Ben t h. Twpinia insignis ( H BK.) T u lasne Zamhoxylum kellermanii P. Wilson

Another important zone of decid uous forest was descri bed by Sousa in the Sierra de los T uxtlas (Sousa, 1968) where he found the following species : Dominant species Liquidambar macrophylla Oerst. Quercus skinneriBenth.

Ulmus mexicana Uebm. Meliosma alba (Schlech t.) Wa lp.

.~ .

In contrast with the forests, the selvas are tree communities which are composed and dominated by several species of trees. There are several vegetation types included in this category which a re m ainly determined by the distribution and total amount of rainfalL Sel vas are the characteristic vegetation types of the tropical lowlands of the world. They have been called rain fo rests and tropical fo rests, but neither of these terms seems to be adequate (Gomez-Ponipa, 1965). The classification of the selvas uses two principal parameters: the height of the communities and the percentage of deciduous tree species.

'! 106

A. GOMEZ-POM PA

Higli seh•as

These are 25 or more m tall and arc fo und in areas wit hout a pronounced dry season and with a total precipitation of more than ca. 2,000 mm. ( 4) High e1·ergreen seh•as. This is the tallest vegetation type in Veracruz, where it grows in the more humid, wa rm areas of the state with precipitation from 2,5005,000 mm or more per year and with few if any dry months. One of its characteristics is that 80% or more of the component species are evergreen, or at least they do not foll ow a definite pattern of leaf fall at one time. This vegetation type is the one known as "tropical rain forest", "rain forest", "wet tropical fores t", "evergreen tropical forest" or combinations of these names. In Veracruz this type of vegetation is found at the lowland flatlands at the base of the mountains a nd at the so uthern end of the state. Jn the Sierra de los T uxtlas it occupies a great portion of the slope at altitudes below 7()0 m. Some meteorological stations are situated in the area where these selvas used to grow, and data from them can be seen in Fig. IS.

These sclvas grow in different types of soils, but most commonly in deep yellow lateritic soi ls (Table V) wit h good drainage. [n the Sierra de los Tuxtlas area they also occur on brown soils derived from volcanic ash and even .on lava beds with soil underneath. In the sout hern portion of the state (Leon C. and Gomez-Pompa, 1970) such communities form a vegetation mosaic with other vegetation types because of soil differences produced by microtopography. There arc many kinds of communities within the vegetation type in these areas, where a small soil difference gives rise t o a differen t combination of speci~s, both in quality and qua ntity, as ca!1 be seen in two quadrats made a few meters apart at different soil levels (Tables IV, VI). Some species characterizing this type are the following: Dominant species Dialium guiwtense'(Aubl.) Sandwich Terminalia amazonia (Gmcll.) Excll. Calophyl!um brasilieme Cam b. Other ;pecies (continued on p. 108) Andira inermis H UK. Brosimum alicnstrum Sv.'. B

l atit ude

18 ° 19'

Lo ngitude

94'25'

Alt i tude

14 m

107

ECOLOGY OF THE VEG ETATfON OF VERACRUZ

Latitude Long itude Altitude COYAM

16'26' 95'00' 340 m E

Ave ra ge annu al temperatu re 23.4°C To t al annual rai nfa ll 44 39.8 mm

CO ATZ ACO AL COS Ave ra ge on nuol t emperature 25.3 °C Tot a l ann ua l ra infall 272 6 .2mm

e.. ~

3 l:'

'E ~

c 0

·:;

2:>

·a.

:5c 0

·;:;

1'0.

"'l:'"

2:>

::;:

Fig.18. Climatographs of stations located within the region of the high evergreen selvas. A. Coatzacoalcos station; B. Coyame station.

3 0

~ ~

E ~

.sc .2

2:>

.... 2

!0c

""'l:' ">

" ~

2:>

:5c 0

::;:

lOS

A. GOMEZ-POM PA

Cephaelis tvmentos11 (A ubi.) Yah! Cupania demata DC. Cymbopetalum baillonii Fries Cymbopetalum penduliflomm (Dtmal) llaill. Cynometmretusa Hr. et Rose Deudropwwx arboretl.l' (L.) Dccnc. et Phmch. Genipa americana L. Guarea chiclwn C. DC. Gum·eatonduzii C. DC. Gnotlerio amplifolia Triana et Planch. flirt ella mcemosa Lam. Jacamtia dolidwula (Donn. Sm.) Woods. Licania hypoleuca Bent h. Licaria peckii (Johnst.) Kostcrm. Matayba oppositifolia (Rich.) Brill on Mortoniodendron sp. Ormosia ist/unensis Standi. Podocmpus grwtemalensis Standi. var. pinetomm (Bart.) Buchh. et Gray

Po.\·oqueria latifolia (Rudge) Rocm. et Schult.

ECOLOGY OF THE VEGETATiON OF VERACRUZ

Pouteria campeclriana (HilK.) B:tehni l'.l'eudo/media oxyphyllaria Donn. Smith Rinorea guatcmalensis (Wats.) Bartl. 1/heedia edu/i.1· (Seem.) Triana ct Planch. Salacia belizen.l'i.1· Standi. Saprwrtlws all'.Jwmi/is Miranda Scheelea liebmmmii Bccc. Simarouba glauca DC. Sloauea tuerckheimii Donn. Smith Sphaeropleris myosuroides (Liebm.) Tryon Stdm!ia apetala (J acq .) Karst Stercn/iamexicana R. Hr. Swietenia macmphylla King Tapirim macrophylla Lundell Trichi/ia hirta L. Trophis mexicamtm (Ucbm.) Bur. Tu11Jinia an·.pcmiculata Vent. Vochysia hondurensi.1· Sprague Xylopia/rlllescenl· A ubi. Zue/ania guidonia (Sw.) Britton et Milsp.

TABLE IV QUADRAT

Domi-

Of HIGH EVERGREEN SELVA OF

Name

IIliilCC

Terminafia 1/1/laZOIIia

Number Freofindi- quency t•iclua/s (%)

JN THE COATZACOALCOS REGION

Maxi- A''erage mum height height {111)

Coverage {m')

Ba.m/ area (cnn

(111)

Termina/ia amazonia

40.0

29.00

15, 11 6.10

582,698.0

Tapirira macrophylla

30.0

(Caobilla) Brosimum terrabanum (Ojochillo)

14.89

1,383.55

23,341.5

20.0

14.20

981.55

14,521.5

Podocmyms guatemalensis

25.0

(Palo de Campana) Jnga sp. (Palo Tinto)

18.33

1,250.51

11,499.0

25.0

25.00

565.45

11,1 82.0

Cupania dell/ala

Hirtella racemosa

(Suchi Amarillo) 2

5 80

12.0

8.94

1,287.60

8,787.5

15.0

8.31

910.55

6,750.5

(Tres Lornos) (Icaco Verde) 8

Dialium guianense

15.0

11.17

742.0 5

5,284.0

(Paque) Guarea sp. (Palo Bejuco)

10.0

7.07

686.80

5,023.0

Sapranthus humilis

15.0

10.80

400.40

4,630.5

23,324.56

673,717.5

Other species (25) Total 1

450

After Leon and Gomez-Pompa (1970).

::: 't

.Q I

I~ iE

>rl

109

110

A. G6MEZ-POMPA

ECOLOGY OF THE VEGETATION OF VERACRUZ

T ABLE VI QUADRAT' OF A I·IIGII EVEHG RHN SI:LVA OF

Dia/ium guianense

The fo llowing species characterize these sclvas: GROWING IN A MORE II UMID SOIL THAN

TilE ONE IN TABLE IV

----· Domilwnce

Name

Nrunber ofindi••iduals

Frel}ftCIICY

(%)

Dominalll species

Maxi- Average mum height height (m )

Coverage

Basal area

(m')

(em')

Bemou/lia/lammea Oliver Bro.rimum a/icasrrum Sw.

Ficrutecolmensis(Licbm.) Miq. Pseudo/media oxyplryllaria Donn. Smith

(III) Dillliwn guianense

Orher species

25.5

7,902.50

124,863.0

28.4

3,392.80

111,911.0

(Paquc) 2

Tcnninalia amazonia

(Suchi Amarillo) Triclri/ia sp. (Caobilla)

25.0

2,136.20

32,713.0

Guatteria amplifolia

15.5

1,040.60

10,617.0

(Palo Calabaza)

Guarea chic/ron

8.3

1,428.30

8,702.5

(Palo de Bejuco) Licania sp. (Mierda de Nino)

25.0

1,258. 10

6,360.5

Dendropanax arboreu.1·

9.4

946.25

6,170.5

(Carne de Pescado) Cupania an·. dentata DC (Palo Colorado)

13.3

646.95

5,140.0

Clusiasp.?

25.0

565.45

3,589.0

10.5

467.20

2,789.0

19,784.35

312,855.0

(Ciempie) 10

Cupania dentala DC (Tres Lemos) Other species (18) Total

200

Ill

• After Leon and Gomez-Pompa (1970).

Three species on this list that need further discussion are Podocarpus guatema/ensis, Quercus oleoides, and Sphaeropteris myosuroides. They seem to be out of place in this type because, with the exception of Sphaeropteris, they have not been found growing in these seivas in any other areas in Veracruz or even in Mexico. I cannot find any environmental explanation for this coincidence. The only possible explanation is that they are relicts of the old community that seems to have grown in these areas in the recent geological past when the .area was cooler. The first two taxa are also found in edaphic communities, such as savannas and oak forest, and even in the lowland pine forests of British Honduras (Lundell, 1937). This lends support to the idea that a cooler and/or drier climate was predominant in this area during the last glaciation. The other area of extensive tall evergreen selvas is found in the lowland5 of the region of the Sierra de los Tuxtlas, where several surveys of the vegetation communities have been made (Anonymous, 1965 ; Sousa, 1968).

Albizzia purpusii Br. et Rose Alchomea/atifolia Sw. Annona muricara L. Annona purpurea Moe. et Sessc ex DunaJ Annona retiwlatt1 L. Andim ga/eollimra Standi. Astrocaryummexicamrm Liebm. Bacrris bacu/ifera Karw. ex Mart. Bactris co/rune Watts Bursera simarubn (Sw.) Sarg. Ceiba pentaudra (L.) Gacrtn. Clramaedorea a/temaus Wend!. Clramaedorea emesti-augr/Sii (H. Wend!.) Oerst. Chamaedorealindeuiana Wend!. Clramaedorea oblongata Mart. Clwmaedorea tepejilote L iebm. Crataeva /apia L. Dendropanax arboreus (L.) Dccne. et Planch. Dus.ria mexic(//ra (Standi.) Harms Ficus insipida Willd. Guarea bijuga C. DC. Gum·ea glabra Vahl Hampea nutricia Fryxcll Lcnchocarpus crrrclllus Lundell Lonc/wcmpus guaremalensis Ben th.

Louclrocarpus stmlarosmms Donn. Sm. Ma/met1depresm (Baill.) Fries Mortoniodendron grwtcma/ense Standi. ct Stcycrm.

Omwsia istlunensis Slandl. Picranmia 0111itlesma L. PiCI'amnia terramera Turcz. Pimenra dioica L. Pithece/lobium arboreum (L.) U rban Plertrantlrodendron mexicomm1 (Gray) L.O. WilIiams

Poulseuia armata (Miq.) Standi. Psychorria spp. Pterocorp11s hayesii Hems!. Quararibeafimebtis (La Llave) Standi. Reiulumlria gracilis (H. W.) Burrett Robinsone/la miraudae G6mez-Pompa Sapiumnitidum (Monach.) Lundell Sloaueasp. Terrorchidium r·otundatum Standi. Thouinia paucidentata Radlk. Trichi/ia brevif/ora Blake et Standi. Trichi/ia tomemosa HBK. Vatairea lundellii (Standi.) Killip ex Record Vochysia hondurensis Sprague

Relicts of these selvas can be found in many other areas, but in most cases the original vegetation has been destroyed, and it is difficult to reconstruct the original selvas. Chiang (1 970) reconstructed the primary selva in the Cordoba region; he mentions the following species : Dominant species Tenninalia amazonia (Gmell.) Exell. Other species Astronium graveolens Jacq. Castilla elastica Cerv. Miconia argentea (Sw.) DC. Stemmadenia donne/1-smithii (Rose) Woods.

Tabebuia rosea (Bert.) DC. Zam!toxylum belizense Lund. Zuelania guidonia (Sw .) Brit!on et Milsp.

One of the most striking things about these communities is that they tend to form floristic units locally that can be distinguished rather easily by a person well acquainted with an area. These groupings may be used to extrapolate soil conditions

La titu de Long i tude Alt itude

18'54' 96'56' 927 OOm

Lot otude 20' 27' LOngo tude 97'19' A l to tudc 29800m

CORDOBA

PAPANTLA

DE OLAR T E

Average annual temperature 24 o•c Total annual r ain f a ll 1169.9mm

Average an nua l temperatur e 20.4°C Total an nu a l ra in to II • 2199 .1 mm

30 30

600

500

e .5c 2

'ii

5c 200

."'.\

.,~

300

.,c

;:;

400

·-·--._.·.. . . ._

20-

700

600

"r" 400

300

·a. fQ

5 200

100

" .,E"'

.I 5 100

Latitude Long itude Altitude

20' 4' 97'3' 151.00m

MART I NEZ DE LA TORRE Average annual temperature 24.0 111 C Tota l o nnu al roinfa ll 1743.4mm

A M

A Latitude Longi!ude Altitude

19"56'

96'50' 410.00m

M I SANT L A Average annu al temp erature 22.7 •c Tot al onnuol r a i nfall 2275.Qmm

700

600

500

'E .5 c

.!? 2

E' £

5c 0

.,E

.,E"'

::;:

Fig.l9. Climatographs of stations located within the region of the high semi-evergreen selvas. A. Cordoba statio n; B. Martinez de Ia Torre station; C. Papantla de Olartestation; D. Misantla station.

114

A. G6MEZ-P0 Ml'A

ECOLOGY OF Til E VEGETAT IO N OF VERACR UZ

115

TA BLE VI! QUADRAT' 1'1\0M A II lull SF-'IHVUtG it HN SELVA IN T HE CO ROO IIA REGION, G KOWING ON LIM E~.,.ON E liiLL~

Domi-

Name

IWJ/Ct:

Ficu.,· recolutensi.v

Number ofimliritlua/s

Fretj/ICIIC)'

(%)

-------r - 5

(Higuera) 2

Brm"in111111 alicMtrum

Acltras zapota

--·-~--

40.00

2,260.80

203,409.0

32.50

3,533.45

53,961.5

30.00

2,5 13.60

36,050. 5

32.50

2,575.30

26,725.5

35.00

1,570.00

26,896.5

35.00

1,570.00

19,256.0

20.00

2,421.90

11 ,1 18.0

35.00

62.80

10,1 12.0

30.00

645.50

7, 197.0

30.00

141.35

(Chicozapot e)

Cedrt:la odorata (Cedro)

Cocco/oba sp.

Croton uiteus

(Coma1illo Macho) (Vcntosidad )

Bemoullia flwnmea (Piatanillo)

9 10

Sapi11111 lateriflomm (Mameicillo) Lancltocarpus sp. (Sangre de Tore) O ther species (13)

- ------·1

( m')

Ba.ml area (em')

(Mu1ato) 4

Co l'eragc

(Ojochc)

Bursera simamba

--- ---·-

Maxi- Average mum height lteigltt ( m) ( m)

3,896.5

Achra.1· zaJwla L. Ampe/ocem lwtllei {Sta ndi.) Stand i. AspidoS{Jerma mt•galumrpun Mucll. A rg. A.stronium gra1'eolens Jacq. Bemuulliaflammea Oliver Bumlwx e/lipticum HI3K . Bunclrosia/anceolata T urcz. Bursera .liiiWmba (Sw.) Sarg. Cttpparis baducc/1 L. Cedre/a odomllt L. Cordia alliodura (Ruiz ct Pavon) Cham . Cupania dentata DC. Dioscuretlmexictma Guill. Exostema mexicamm1 A. Gray Exothea copalillo (Schlecht.) Rad lk. Ficus cuoki Standi. Ficus tecoluteusis (Licbm.) Miq. Guettardt1clliptica Sw.

llrx wndensataT urcz . lngasput'ia H UK.

Mirwulact"!tix mvnoim ( Hems!.) Sharp l\'1;-riormpa bijitrc/t Liebm. M)"roxylun bal>tlllll/111 (L.) H arms Nt•t·tandm sanguittea Rottb. l'errottctialoagistyli>·Rose Platymisfium yuC{Ifanwa Sta ndi. Protiwn copal (Schlecht. ct Cham .) Engl. Robinsonella mirattdae G omez-Pomp a Sopiwnl/llenflorum Hems!. Sickingia rlwdoclada (Stan d i.) Standi. Stcmmadenia donne/1-smit!tii (Rose) Woods. Tric!tilialtavanettsis Jacq . Tricltilia hirta L. Urera baccifcra (L.) Gaud. Vatairealt~ndellii(Sta nd l .) Killip ex Record

TAl3L E VI II QUADRAT OF A III GH SEMI-EVEKGR HN SELVA OF Brosinlltlll (1/iCII.I"Irlllll IS T HE I'OZA KICA REGION; THIS SELVA GROWS ON SOIL DE RI VED FROM CALCAREOUS 1\0 CKS

- - - - - - - - - - -·- -- --

Domintmce

Name

Number Frcofindi- quency 1•idua/s (%)

M a.ri- A rerage fteigltt mum fteigftt (111)

Co l'erage

(ni')

Basal area (em' )

(ttt)

·------

After Chiang (1970).

Brosimwn a/icastrtm1

60"

27.0

24.0

250,615.0

3,510.50

30.0

29.5

2 18,626.0

5,102.70

2 1.0

15.8

7,873.0

192.00

27.0

6,442.0

125.60

140

12.5

6.5

4,82 1.0

770.50

19.0

3,361.0

70.60

6.0

5.8

562.0

112.80

6.0

229.0

50.00

(Oj ite)

within the same area (Cuanalo and Aguilera, 1970). What cannot be done is lo extrapo late fro m one region to another (Gomez-Pompa, 1966).

Mirandaceltis monoica (Pi pin)

Castilla elastica (Hulc)

{5) High semi-erergreen selvas. This vegetation type also.a rises in humid a reas bul may be found in areas with rainfall as low as 1800 mm and with a few dry months, as may be seen in Fig. l 9. The data come from meteorological stations within the ranges of distributio n of this vegetation type. High semi-evergreen selvas may be characterized by the considerable po rtion of the tree species (up to 40 %) which have leaves deciduo us in the dry season. It is also found in areas with the &ame climate as the evergreen rain forest, but on special soil conditions , such as well-draine d rocky so ils. A good example of this last situation, presented by Chiang (1970), was found in the limestone hills of the Cordoba region where the quadra t ofTable VII was surveyed. The floristic compositio n reported for this selva is the following: Dominant species Brosimum a/icastrwn Sw.

Zuelaaia guidouia ( N ogalillo)

Guarea clliclwn (Hoja Blanca)

Pitftecellobium insigne

(Chalahuite de Espina) 7

Tabemaemolllana alba

(Coj6n de G a te) 8

lresine nigra

(13agacillo) 9 10

Alc/wmea latifolia (Pa lo Blanco) Piper aff. misantleuse (Cordoncillo Chico) Other species (45) Total

6.0

179.0

31.40

5.5

179.0

31.40

492,887.0

9,997.50

410

116

A. GOM EZ-POMPA

NAOLINCO

MISANTLA

ECOLOGY OF TH E VEGETATION OF VERACRUZ

COLIPA

Pimcuta 1/ioica L.

Pleumntlwdellllron mexiclllwm (A. Gray) L. Protium copal (Sch lecht. ct Cham.) Engl. Pithecellobium arboreum (L.) Urban Sapindus saponaria L. Sapium/ateriflomm Hcmsl.

117

Scltei•lea /iebmwmii Bccc. Sll'ietenia macrophylla King Trh-hilia hirta L. Trophis racemo.m (L.) U rban Urem caracasana(Jacq.) Griscb. Zuc/auia guido11ia (Sw .) Bri tto n c t Millsp.

Most of the soils in this region are derived fro m calcareous rocks which adds another element o f selection for the flo ra, and m a_kes it q uite uniform. This vegetation type has been considered t he northern limit of the rain fo rest in America (Rzedowsk i, 1963). I t seems that several of the species I ha t compose it are tolerant. to occasional low temperatures. This allows them to colonize some protected habitats in the extreme tropical conditions. One fact favorin g this hypothesis is that many of the species are also·fo und on t he Pacific Coa st in simila r cond ition s where they are tolerant to the extremes of t he tro pical climate. They are a lso found _in protected areas such as canyons and near river banks (Gentry, I 942, I 946) as far nor th as Sonora . Some of these species are: " 'Go;

"'G" ~tM\'IYI~•tlro

~( ,. q¥ (1(;1(( N

M0NfA.Nl ~(IY4

~h ....

O u :; tOf l\f

Fig.20. Vegetation pro fil e in centnil Veracruz (Naolinco-Colipa) on the Sierra of Chiconquiaco.

A very similar gro up o f species has been reported from limestone hills in Oaxaca (Gomez-Pompa et al. , 1964b). Apparently the limestone and rapid drainage combine to have a highly selective action on the available species. This vegetation type could have been fo und in alrthe lowland areas with welldrained soils, from the Misantla region up to Tuxpan and even north of T uxpan along the river banks. M ost of these selvas have been d estroyed by man but there are a great number o f patches remaining that give a fairly good id ea of their original structure (Table VIII ; Fig.20). Among the species known from these selvas, the fo llowing are characteristic: Dominant species Brosimum alicaslrllm Sw. 0 I her species Achras zapata L. Bumclia persimilis H emsl. Bw·sera simamba (Sw.) Sarg. Carpodiptera ameliae Lund. Castilla elastica Cerv. Ceibapentandra (L.) G aertn. Chamaedorea lunata Licbm. Ch/orophora tit1ctoria (L.) Gaud. Cupania denlata DC. Dendropanax arboreus (L.) D ecnc. et Planch.

Diospyros digyna Jacq. Enallagma lat1/olia (Mill.) Sma ll Ficus iusipida Willd . Guazuma ulmifolia Lam. Iiemaudia sonora L. Mastichodendron capiri (A. D C.) Cron. var. tempisque (Pitt.) Cron. Mirandace/tis monoica (Hems I.} Sharp Misanteca capita/a Cham. ct Schlech t. Phoebe mexicana M eissn.

Brosimum alicastmm Sw. Urera carac(lsana (Jacq.) Griscb. Chloroplwra tinctoria (L.} Gau d.

Guozuma u/mifo/ia Lam. Sapindus saponoria L. Trichilia hirta L Trophis racemosa (L.) U rb.

These selvas of the extreme northern tropics may have occu pied a much wider distribution in the colder geological past, and the commu nities that today seem to be disjunct were part of the same genetic stock. Very interesting experiments may be designed to evaluate the degree of population differentiation in some of the common species from the Pacific and Gu lf coasts. Th is is especially interesting, because it seems that the species of the Pacific have a wider soil tolera nce than those of the Gulf. A n example of this is Brosimum a/icastrum that grows in different substrata in N ueva Galicia (Rzedowski and McVaugh, 1966) and is not restricted t o limest~ne s as it is in northern Veracruz and San Luis Potosi. I n the lower part of the mountains in very wet regions, the Liquidambar fores ts and the lowland high selvas come in contact, and a different and very interesti ng semi-evergreen selva develops, with flo ri stic elements from both sides. This is a very tall vegetation that may reach more than 40 m in height. This selva is not well known and d escriptions are scarce. The mixture of high humid ity and moderate low temperatures creates a unique etlVironmen t, and many genera and species are known in Veracruz only fr om such selvas. Because of t he abundance of species of the fam ily Lauraceae, it has been called Selva of Lauraceae (Gomez-Pompa; 1966), and it is shown in the profile in Fig.20,2l as high montane semi-evergreen selva. Some of the species known fro m this kind of selva are: Alchomea latifo/ia Sw. Beilschmiedia anay (Blake) Kosterm. Beilschmiedia mexicatla (Mez.) Kosterm. Calato/a laevigata Standi. Ceratozamia mexicana Dron gn.

Nephelea mexicana (Sc hlech t. et Cham.) Tryon Dalea e/ata Hook. et Arn. Dussia mexicana (Standi.) H arms Ficus lapathifolia (Liebm.) Miq. Hampea integerrima Schlecht.

118

A. G6 M EZ-I'O MI'A

Licaria !IC:Ckii (Johns!.) Kostcnu. Miconia rrincn•ia (Sw.) Don Mirmulacelri:l" moJIOfca ( Hems!.) Sharp Nec/mulm salicijiJ/ia 1-1 B K. Ocoretl ••eraguensi.1· (Mcissn.) Mcz Pe1·5ea schiedeaJUt Nccs

!'ilea pube.1cens Licbm. Piper sancl/1111 (Miq .) Schlecht. J'ou/senia armaltt (Miq .) Standi.

Que.r.c.J.Js t:tuTuJ:ala I look.

Q11Crcu.1· aiL 11racili11r Mull . Quen·u.1· .l"kinneri !lentiL Saurauialaevigata Trian;1 cl Planch.

Sp/wemplc'ris hurricla (Licbm.) Tryon Tapiriram(•xicmw M Hrchand

Trimeztlnl/lrlinicemis (Jacq.) Herb. Virola guotemaleusis (Hconsl.) Warb. Ulmus mexil'illlfl Licbm.

VOLCANO OF SAN MARTIN, LOS TUXTLAS , VER.

1500

soo-·- --

LIOUIOIIMBAR FOREST

ECOLOGY OFTI·I E VEGETATIO N OF VERAC RUZ

119

munity is dete r mined by such factors a s : water availability, strong winds, and soils. It is probable thai other facto rs incl ud ing a nimals and fi re may also play an impo rtant role. Because of this, the trigger factor may not always be the same. The fl oristic composition of this grou p may a lso vary greatly.

(7) Low el'ergreen selra. T his type of selva is found in a very restricted locality at the top of the volcano of San Martin (Fig.2J ), and probably grows on Santa Marla as well. It is a small, very dense· forest wit h many epiphytes, mosses, and lichens, from which another name fo r this vegetation, "mossy forest", is derived . It is. also known by the na me "cHin fo rest" o r "elfin wood land". These selvas pose an important problem because, even though they grow in a very humid habitat with good deep soils and abundant light that could prod uce a tall forest o r selva, they produce this low selva. There have been several important studies made in Puert o R ico on a similar vegetation type (Howard et at., 1968), but until now without a definite solu tion. For a long time wind has been considered the explanation for t his se lva, but t here is no evidence avai lable that t his is true ( Bayn ton, 1968). However, the q uestion remains open, if periodic cyclon ic disturbances , not necessarily record ed, struck the tops of these mou ntains mo re strongly than the adjacent lands- one strong wind every 20 yearswould this be enough to keep the selva short. In our region in Veracruz, -ihis seems clearly to be the case, as mentioned by Sousa (1968) in his observations after a cyclonic d istu r bance struck the a rea. Another ecological factor not considered normally is the low light intensity throughout the year in this type. Genecological studies seem to be needed to help solve the problem. The only locality known in Veracruz for this vegetation type is the top of the San Martin volcano; from this area Sousa (1968) mentions the follow ing species:

40~~

Clusia salt•inii Donn. Smith £1/eautlws capiratus (P. et E.) Reichcnb. f. Gaultheria nit ida Bent h. llcxsp. Lirseasp. Mouninasp. Myrica cerifera L.

In this group a heterogeneous a rray of vegetatio n types occur~. The . height of t l1e types to be considered here do not exceed an average of 10m. The stature of any com-

(8) LoiV semi-el'ergreen selvas. In drier a reas (ca. 1,400-!,800 mm rainfall), or in more humid areas with poor soils and with drainage problems, these selvas can be found (Fig.22). They are very large in extent because many of them give very poor agricultural yields and are used o nly fo r certain crops, such as pineapple and some grasses that can maintain only a few cattle. In some of these areas there is a strong suspicion that t his vegetation type may be of secondary o rigin, bu t t here is not sufficient evidence. T his type is strongly related to the tropical lowland oak forest and to the savannas, and varieties of it are often f ound together forming a complex mixture of types called "selvas sabaneras". Floristically they are also closely related to these, and it seems that in several cases one type ca n give rise to the other, given certain human practice& (slash-burn agriculture).

Fig.2 1. Vegetation profile oft he San Martin volcano (Los Tuxtlas).

{6) Medium semi-evergreen selras. T his vegetation type is about 15-25 m tall. Up lo

or more of its species have deciduous leaves. [t grows in different climates but is found mainly in drier areas than the p receding types (in places with 1,400 mm or more rainfa ll and with a · pro nounced dry season). They are also found very frequently in drier areas but along the river banks. Tt is d ifficult to characterize t his type of selva flo ristically because it is intermediate , being composed of the drier tolerant species of the ta ll selva~, the more humid represen tatives of the low selvas, in addition to a few species of its own.

Low seh>as

Orcopanax xalapense (H BK.) Decnc. et l'lanch . Policourea galeolriana Marl. Rapauea jurgemenii Mez Saw·auia villosa D C. Senecio arborescens Stcetz Vibumummonranum Lundell

rA--·---------------------Lot• tude Longitude Altitude RODRIGUEZ

19'39" 95°25' 148m

ECOLOGY OF THE V EGETATION OF VERACRUZ

CLARA

Average annual temperature 26.3°C Total annual rainfall 14353 mm 30

E "c

·-·"'.--·--.....

~ E

"·\

700

··-

Ave rage annual t ern perature 25.6°C Total annual rointoll 1401.5 mm

6oo"E

500

~ :;:;

4QO

.'l

8E "'"'~ ">

a 300 10 r--

:hr; ..

......r·

~-.~.-~ . -:::~:.•-:;p:-1 . -. •..., •.., , J

200

F M A M J

,~,,i.

j·

600

500

.'::

400

2 "ii

300

~ a

..g

200

N D O

B Latitude Longitude Altitude

"E E c ·;;

""'c ">

100

r:~·

. 1: :l

A S 0

700

:liJ-q_

I :

: ' ' ' /i'm l,il!

3"'c 0

p;;;

·•

L otitude 2o•n· Longi t ude_ 96'46' A l titude 8.00m

NA U T L A

.........

121

100

17'47' 95°11' 39.00m

JASOND BE L LACO

Average annual temperature . 25.7°C Total annual r ain fall 15B5.2mm

A few of the tree species may be deciduous, but most are evergreen. This vegetat ion type is also very widespread in other tropical regions of Mexico a nd in tropical America under differe nt names; it is designated as a special type of savanna or savanna-like vegetation (savanna woodland, cerrado, selva sabanera) a nd in most cases there is no explanation for its occurrence. T his problem also remains open. The follo wing species are characteristic :

E "c

"a E

c ·;; 0

.'::

Acrocomia mexicana Karw. Byrsonima crassifolia (L.) DC. Curatella americana L.

Psidium guajava L . Crescentia cujete L. Coccoloba barbadensis Jacq.

·;;

, :c a

""'c

Fig.22. Climatograph of a station in the region of the low semi-evergreen selvas. A. Rodriguez Clara station; B. Bellaeo station; C. Nautlastation.

(9) Low deciduous selvas. In the dry warm lowlands this vegetation type seems to be the most widely established one. It is found in regions with Jess than 1,500 mm precipitation and with a pronounced dry season that may last more than six months (Fig.23). It may be up to I 0 m taU but is usually shorter. During the dry season most of the trees remain leafless and very few plants remain active (Janzen, 1970; Fig.24). The structure of the selva sampled n ear Puente Nacional can be seen in Fig.25. This community grows in soils that are derived from limestone and are of dark color, but the same vegetation type is found on other substrata.

Latitude Long1tude Altitude SOLEDAD

19 ' 3· 96'25'

ECOLOGY OF TH E VEGETATION OF VERACRUZ

77m

123

DE DOBLADO

Average annua l tern perature .25.4 oc Total annual r ainfall 943.8mm

700

600 5 c 0

500

!l (l

400

" L

.."'

300

~ >

200

:?.> L

c 0 ::;:

5 100 0

lvl

N 0

Latitude Longitude Altitude

1 8 ' 53' 96'17' 1B00m

CAPULIN ES Average annual temperature 25.8'C Total annual rainfall 1366.1 mm

700

2 ~

" E

.§

·z

.?-

;;

·o.

Fig.24. The low deciduous selvas have a great number of xerophytic plants, such as Acanthocereus , Agave, Nopalea that can be seen in this photo.

The floristic composition of these selvas is quite different from that of other vegetation types. The following species are characteristic:

·;:;

Dominant species

!?"'

:?.>

;;

" >

::;:

Cordia dodecandra D C. Crescentia alata HBK. Emerolobium cyclocarpum (Jacq.) Griseb.

Piscidia piscipula (L.) Sarg. Tabebuia chrysant!Ja (Jacq.) Nicholson Tabebuia rosea (Bert.) DC. Other species

Fig.23. Climatograph of a station in the region of the low deciduous selvas. A. Soledad de D oblado station; B. Capulines sta tion.

Acacia comigera (L.) Willd. Acaciafarnesiana (L.) Willd. Acanthocereus pentagonus (L.) Britton et Rose Aeschynomene compacta Rose

Agavesp. Bunchosia bioce/lata Schlecht. Bromelia pinguin L. Bw·sera bipinnata Engl.

I 124

Loti tu de

22'14' 9 7"51 ' 12.00m

Long it ude Alti t ud e?

A. G6MEZ-I'OMPA

T AM P I C 0 , TAM P 5.

JALAPA~VERACRUZ

Avcr·a~e

an nual tem pera ture 2 4 .3'C Tot al onnuol rain f all 1079.9 mm

/·-·-·,.

~ ~ ~

l:> ~

,.,

"·\

/./

700

500

E .§

500

c 0 ·.;:;

:;:

400

" ~

2' 300

01 0

200

::t:

5 100 llQ UIOAM8MI· OAK f0R£SI

GRASSLAND

lOW DECIDUOUS SElVA

COASfAL V (GUATION

0 F

Fig. 25. Vegetation profile of the region between Ja lapa and Vcra~ruz City.

Bm·sera }itgaroides (H BK.) Engl. Bursera simamba (Sw.) Sarg. Byrsouima crassifolia (L.) DC . Casearia nitida (L.) Jacq. ·celtis iguanaea (Jacq.) Sarg. Cltloroplwra tiuctoria (L.) Gaud. Citlwrexylum ellipticnm Sesse et M oe. Comoc/adia engleriana Loes. -cordia pring/ei Robinson Coutarea hexaudra (Jacq.) Schum. Cratael'a /apia L. Croto11 g/andrtfosepalus Millsp. Croton puncta/us Jacq . Cupania macrophyl/a A. Rich. Cumtella americana L. Dalbergia g/abra (M ill.) Standi. Dap/mopsis brevijo/ia Nevi. Dioon edule Lind!. Erythroxylon m·eo/atum L. Eugenia liebmannii Standi. Ficus cotinifo/ia HBK. Ficus maxima P. Mill. Ficus obtusifo/ia HBK. Guettarda elliptica Sw. Haematoxylum brasi/etto Ka rst.

Hamelia patens Jacq. Jatrophapseudocurcas Muell. Arg. Luehea speciosa Will d. Mabavem e-cmcis Standi. Nopalea dejecta Salm-Dyck Okeuia hypogaea Schlecht. ct Cham. Opulllia pubemla Pfeiff. Parmentiera edulis DC. Phyllantlws grandifo/ius L. Phyllam/ws nobilis (L. .f) M uell. Arg. Pithecellobim11 calostachys Standi. Pithecellobium erythrocarpum Standi. Plumeria acutifolic! Poir. Randia acufeata L. Ran(/ia albonervia Brandeg. Sabalmexicana Mart. Sageretia efegans (HBK.) Brongn. Salvia coccinea J uss. Sapium sp. Tamonea curassavica Pers. Tlrouinidium decandrum (H. et B.) Radlk. Trichi/ia havanensis Jacq. Trichilia parvifo/ia C. DC. Zanthoxylumfagara (L.) Sarg. Zuelania guidonia (Sw.) Britton ct Millsp.

2 2 ' 3' 99'11' 22.00m

Lotitcde Longitude A ltitude PANUCO

Average OI1Tlual tempera tu re 23.8'C Total an nual rainf a ll 915.5mm

. . . . -·--·-·

;·

E ~

.::

l" ~

E ~

,.,

"·

'-..._

"""·

E .§ c 0

.8 Cl ·v

"....

c 0

::;:

{10) Low thorn seh·as. This vegetation type is found in the driest regions oflowland areas where precipitation is under 1,000 mm and where the dry season is long and Fig.26. Climatographs of stations in the region of the low thorn selvas in northern Veracruz. A. Tampico station; B. Panuco statio n.

126

1\. G6MEZ-I 'OM PA

ECOLOGY OF TilE VEGETATION OF VERACRU Z

127

pronounced (Fig.26). T hese regions a lso have the lowest winter temperatu res in the lowlands. The co mbined efrcct o f these highly select ive litctors gives rise to the very character istic flora, which is a combination of floristic clements from the more h umid a reas in the sout h and the Tamaulip as desert s in the north. T he soi ls of th is northern area are very dark in color and a rc clayey, b ut otherwise no t well known. Among the species fo und r mention the following that arc fl o ristically characteristic of this vegetatio n type: Abulilon /rique/rum A. Rich. Acacia collstricta Dent h. Acacia lcxew;is T. ct G. Aclw /ocw1111S 11ig ricans Triana Boerlwl'iu erec/a L. Cordia alba (J acq.) Rocm . ct Schult. Cordia boissieri DC. Coursetia axil/uris Coull. ct Rose Cltloropltom tincloria (L.) Gaud. Cillwrexyltmt berlmulieri Robins. Cro/OnnilemÂˇ Sw. Erylltroxyloll areolatwn L. Eugenia licblltattttii Standi. Guazuttw tdmifo/ia Lam.

Jacqui11i11 axil/oris Ocr st. MalfJigftia flllllicifo/ia L. Mimosapigm L. Morrisonio ttmericano L . Nopalea cocltenil/ifcra (L.) Salm-Dyck Parkimonia aculcula L. Pltyllallllws micrandms Mucll. Arg. Plumbago sp. Pilltecel/obiwll sp. Randiasp. Solannmlanceifolitmt Jacq. Scltoepjia scltreberi Gmel. Tric!tilia parl'i/olia C. DC. Zyzyp!tussottorettsisS . Wats.

(I 1) Palm slands. This vegetation type is rat her widesp read in the humid and subhu mid lowlands, where two principal kinds may be distinguis hed: the Schee/ea palm stands and the Saba/ palm stands. Physiognomically these may be distinguis hed easily by t he pinnate leaves of the fi rst gen us and the fan-shape d leaves of the second. The Scheelea /iebmmmii palm stands have been considered an anthropo genic vegetatio n type, since th is plant is protected and conserved during the usual destruction of the vegetatio n as it is used for many purposes, such as ho use construct ion, firewood, and food. As this palm is a principal compone nt of other vegetatio n types such as the tall evergreen, the semi-evergreen and the medium semi-evergreen selvas, the destructio n of such selvas favors the spread of this palm, which forms dense secondary communi ties d iflicult for any other trees to compete. Even thoug h most of the palm stands in t he state are of this origin, there are several places in which this palm is domi nant, where no direct evidence links the palm stands with luunan activities. These- primary palm stands are fo und in soils that are inundated during a large part of the rainy season (Fig.27); they are composed floristically of many species with similar ecology. Some of the t ree species that character ize this type of vegetatio n are: Albizzia purpusii Br. et Rose Bunchosia lanceo/ata Turcz. Cit!tarexylum hexangulare Greenm. Cupania dentala DC. Pleurantltodendron mexicanum (A. G ray) L.

Sapi11dus saponaria L. Sclteelea liebmanii Becc. Stemmadenia galeolliana (A. Rich.) Miers Tropltis racemosa (L.) U rban

T he other palm stands, d ominated by Saba! mexicana, is a controversial one. It grows in drier areas with a d rastic dry season, on fiat clayey soils (planosol s) along the coast.

Fig.27. The palm stands of Sc!tee/ea liebmattnii a re very abundant in soils that have a high water table, like this one in the region of Tesechoacan.

f n these area~ fire s are very common during the dry season, and it seems that the presence of this palm is favored by fi re {Fig.28). On the other hand, there a re a reas where the palm is dominant and fi1e seem s no t to be as importan t. Addition al work should be d o ne in the field to learn more about the role of fi re on t his vegetatio n type. A quadrat made on one Saba/ stand may b e used as an example (Table IX). Another palm stand of red uced area is the one composed by PawÂˇotis wrightii in the swamps of southern Veracruz. This p alm is also fo und in savannas, but only in soils where t he water table is high and is above the surface for part of the year (Fig.29). Many of the species growing in palm swamps are found also in inland swamps and will be discussed later.

128

A. G6MEZ-POMI>A ECOLOGY OF T HE VEGETATION OF VERACRUZ

129

T A BLE fX

- ---

Daminance

1 QIJADitAT IN A SAllAL I'AU.I STAND IN TliE RL'GION OF COSMIAI.OAI'IIN

Name

Pilhefellobiwn/anceo/atum

Numbet· o[iudi1•iduals

665

Frelflll!IIC)'

(%) 100

Maxi- A1·cragc mum height (m) height (m}

Col't!rage

Basal area

(m>)

(em')

1 1,7~6.5

5.7

10.0

3,221.0

62.5

(G uamuchil)

Sahalmexinma (1\pachilc)

Zantlwxylunt caribaetmt Ruprechtia coswla

5 30

6.0 6.0

2,248.0 1,490.0

26.5 553.5

6.0

8 14 .0

125.0

Randiaacnleata

4.8

337.0

13.5

(Crucctillo) Acacia cornigera (Cornezuclo)

7 .5

338.0

252.5

(Lagunillo)

Pit!tecel/ol!iwn recordii (Amczquilc)

T otal

750

12,770.0

- ------·--• After Gomez-Pompa et al. (1964b).

Fig.28. The Saba/ mexicana palm stands are abundan t along the coast on flat and clayish soils in climates with a pronounced dry season.

Grasslands There are three main different vegetation types included in this term. They have a very &imilar physiognomy as herbaceous Gramineae are dominant. The first type is the lowland tropical grassland, better known as savanna; the second is the grassland of temperate climates; and the third is the saline grassland. In other localities in Mexico there is an additional type occurring in cool areas in the mountains. This has not been reported yet from Veracruz.

( 12) Savannas. The term savanna (also sabaria, savannah, savana) has been used as a name for a great number of rather different vegetation types. I will use it only for the

Fig.29. The Paw-otis wrightii pahii stands are closely related to the savannas (on the more humid soils) and also to the swamps (on the drier soils).

130

A. GOMEZ· I'OMI'A

ECOLOG Y OF THE VEG ETATION OF VERACRUZ

tro pical lowland grass lands, with or without scallered trees (Fig.30), growing on special soils with drai nage problems a nd, usually, with a aclinitc clay layer. T he savanna s or Veracruz are very much like the cdaphic savannas describe d by Beard (1953) ror tropical America and by Go mez-Pompa (1965) ror Mexico. The proble m with savanna s is that in many cases, especially in regio ns with a pronoun ced dry season, period ic fires may change t he physiognomy or the vegetatio n in the area to a savanna-li ke physiognomy. Several species o r savanna s are preadapted to fire survival and can exploit the resulting new niches. lt is very clear that in such cases soil is not the basic raclor and an anthropogenic o rigin may be suggested. I n other words, a more detailed study should be made to determin e whether certai n

13 1

SABANA COSTERA,COATZACOALCOS

SAVANNA

PAUROTIS PALM STAND

REO LATERITIC SOILS

SAVANNA

ALLU V IAL SOILS

LAS CHOAPAS, VER.

F ig.30. A savanna in southern Veracrul; the tree is Curatel/a americana

areas are true savannas or only have savanna-like seconda ry vegetatio n (GomezPompa, I965). · The savannas are closely related to the tropical oak forests a nd are frequent ly found to share many species. This relations hip depends on the soil types ; the savanna grows on poorer soil than do the oak forests. The savanna s of southeas tern Veracruz have been studied by Leon C. and GomezPompa (1970). Two profiles with savanna s and their adjacent selvas may be seen in F ig.31. Other species from t hese savannas are the following: Paspa/um pectinatum Nees Acisanthera quadrata J uss.

Acrocomia mexicana Karw. ex Mart. Ageratum sp.

SAVANNA

HIG H EVERGREEN FOREST •

SAVANN A

Fig.3 1. Vegetation profi les of a region in southern Veracruz showing the soil differences due to topography between a selva a nd a savanna. A. Sabana Costera, Coatzaco alcos; B. Las Choapas, Veracruz.

Andropogon altus Hitch. Andropogon bicomis L. Bulbostylis afT. paradoxa Nees Byrsonima crassifolia (L.) DC.

Cassia diphyl/a L. Cltamaesyce hyssopi[olia (L.) Small Coccocypse/um sp. Cologania sp.

132

A. G6MEZ-PO MPA

Cmro;-tegia 1>11t:ciosa Naud . Crotalaria sa.t:itta/is L. Cumtelfa llmcricaua L. Diclwomcua ci/iaw Valli Diodia rig ida C ham. et Schlee hi. Elcoclwri!; intcrstiuc/a (Vahl) R. ct S. Fuirenasp. Hibiscus co.!"lllllls Rich. flyplis confer/a Po hl. Hyplisafl'. rugosa L. Kylliuga brwifolia Roub. Me/ochia hirsllla Cav. Mimosa pudica L. Myrica ceri[era L. 0/yra /ali/alia L.

Paurmis wl"if!/llii (Griscb. ct Wend I.) Brit!. Po/ygala aff. adcnop/wra DC. Poln:ala spp. Psidium guajma L. Psidiwumolle llertol. Rhynchalllhcra mexicaua DC. Rhynclwspora all". barbala (Vahl) Kunth Rhynchospora an·. lougispicata 13occckle. Russe/iafloribunda HBK. Saul'agesia erccta L. Setaria geuh·u!tita (Lam.) Bcauv. Spermacocc lwcuckeana Hcmsl. Xyris ambigua lkyr. Zcxmeuia aarea l3enth .

ECO LOGY OF TH E VEG ETATION OF VERACRUZ

, -- -- - - - - -·-Lati tude Longo tude

Att itude P E RO TE

Anthericwn aff.leucocomum R ob. et Grcenm. Anthericumuanum lla ker Asclepias glaucesceus H BK. Asclepias rosea HIJK. Bulbostylis capillaris (L.) C. B. Clarke Cologauia procumbeus Kunth Commeliua dijfusa Burm. f. Cyperus seslerioides HBK. Eryngium carliuae Detar. Heliatropium/ruticosum L. Ipomoea muricata Cav. Microchloa kuulhii Desv.

Nemastylis tenuis (Herb.) Baker Ophioglossum sp. Oxalissp. Piranopappus roseus Less. Quercus peduucularis Nee Rammculus hookeri Schlecht. Selaginel/a sp. Setaria genicula/a (Lam.) Beauv. Sisyrinchium sp. Stevia elarior HBK. Tridax procumbens L. Verbena teucrifolia Mart. et Gal.

The area in which I thin k this vegetation type was more extensive is the Valley of Perote, which has been used for agriculture for a long time. The rainfall here is low enough to cause problems for almost any tree community but is above the upper limit of a typical desert (Fig. 32). Unfortuna tely, today we can find only weeds in all this valley; but two grasses growing in the vicinity give us a clue: Boute/oua curtipeudula (Michx.) Torr.

Bouteloua gracilis (HBK.) Lag. ex Steud.

( 14) Saline grasslands. An edaphic grassland in a temperate region near Alchichica has recently been discovered. It is the only upland saline communit y known in Veracruz. T his grassland occupies a small area in the valley near Alchichica in the states of Puebla and Veracruz. It is a closed deep valley which becomes a small lake or swamp in the rainy season. In the dry season it is completely dry and very saline because of the evaporatio n of water (Fig.33).

700

.. c

25 600

3 Cl

is very poorly represented in Veracruz, if at all. Some areas in the transitional boundary between temperate subh umid to temperate dry climates are covered by a nat ural grassland, although their range is rather limited. The following species have beerr found in one of these grasslands above Orizaba on the lower ~l opes of the Cuesta de Maltrata:

- -...,

19'3 4 ' 97'1 4' 2465.00m

Average annual temperoture 12. 7•c Tot al annual rai nfa ll 525.2mm

..~

( 13) Temperate grasslands. This type of grassland is found in temperate climates but

133

5 00

~ > <{

/·-·-·- ·-· .1 '"'·--.........___,

3 v

400 c

........

c 0 :;

·c.

:5c

'E .5

5"'

300 c

0 }:

200

5 100

A MJJA

Fig.32. Climatograp h of a station located in an area that probably was occupied by a t emperate grassland.

The following species have been found in th is saline grassland: Distich/is spica/a L. Actiuel/a cl11ysanthemoides HBK. Altemauthera repens (L.) Kuntze Aphanostephauus lmmilis (Benth.) A. Gray Astragalus wootoni Sheldon Atriplex pueblensis Standi. Boute/oua breviseta Vasey Croton dioicus Cav. Cuscuta saliua E ngelm. Dichondra argentea Willd.

Erodium cicutimu11 L'Hcr. Gomphrena dispersa Standi. He/iotropium curassavicum L. Hous/onia rubra Cav. Pla!llago niveo Kunth Sanvitalia procumbeus Lam. Scleropogou brevifo/ius Phil. Stipa editoram Fourn. Verbena cauesceus HBK. Verbena cilia/a Benth.

Another edaphic grassland (Fig.34) reported from Veracruz (Vazquez,. 1971) is the Spartina grassland ("espartal") in the coastal region, in Mandinga. These grasslands are inundated periodically, and as a result their soils are very saline. The followin g species have been reported from them: Andropogon g/omeratas (Walt.) BSP. Balis maritima L. Borrichia/ratescens (L.) DC. Fimbristylis castanea (Michx.) Vahl

Fimbristylis spathacea Roth Sa/icornia pel'elmis Mill. Sparliua alterniftora Loisel. Spartina spartinae (frin.) Merr.

134

/\. G6MEZ- 1'0MPI\

ECOLOG Y OF THE VEG ETATION OF VERACR UZ

135

Arid or semi-ari d rege/alion

It is quite d iftlcult to g ive a good definitio n o f ar idi ty that will be satisfacto ry both from the point of view of the vegetat ion a nd of the climate. I am well aware of the problem of u si ng a vag ue cl imatic term in vegetat ion classifica tion but its use seems justifiab le in this case, because of the s harp climatic del imitation of t)1ese vegetatio n types. Such commun ities are very poorly represen ted in the state, and in most ca se~ have been ignored. They arc not represen ted on most general climatic maps, often because there are no meteoro[ogical stat ion s in the areas, so that extrapolation based on vegetatio n is necessary for characte rization.

(15) Nolina-Hechtia-Agat•e desert. T his type of deser t which grows on some of the limestone h ills west ·of Perote, on the border with the state of Puebla, has recently been st ud ied by Ramos (197 1). The climate of the area is very dry (Fig.35), probab ly the driest in Veracru z. The data from the town of Alchich ica on ly a few miles away in the state o f P ueb la may be used for this area. This vegetatio n has been called by Fig.33. T he only halophytic grassland found in the stale grows at the border of the sta tes of Puebla and Veracruz ncar Perote; Distich/is spica/a is the dominant species.

La t itude Longitude Al t i t u de

19'15" 97'32' 23.50m

ZACATE PEC, PUE.

Average onnuol temp erature 14 goc Total annual ra infall 360.8mm

l1 ~

0L ~

~ c

E ~

"'0 L

F ig.34. A halo phytic grassland ("csparta l") near the coast of Veracruz. This grassland is inundated d uring the rainy season for several months. (After Vazquez, 1971.)

c 0 ·;;

500

4 00 "(i

-·o ~

c. ~ r: ~

0 ~

136

A. G6MEZ-l'OM I'A

ECOLOGY O F T HE VEGETATIO N O F VERACRUZ

Lrmrus pldcoidcs H BK . !l'fumillaria dcalbata Brill . ct Rose Mamillaria elcgans Bri tt. ct Rose Salvia cane>·cens llcnth.

137

Sal••ia coultct1 Fernald Sah•ia t ftymoide.\' Bent h. Stipa teuuis.1·imaTrin. Tmde.vcautia brachypllylla G rcenm.

( 16) Thom scrub. T his vegeta tional type is composed ma inly of shrubs less tha n 3m tall, most of them spiny. T here a re two mai n clima tic groups in the thorn scrub : one in high altitudes (1 ,500 m or more) a nd the other of lowland s (less than 500 m ). The main difference is not in the ph ysiognomy but in the fl oristic compositio n, although a se ries of common species is shared . The scrub from the highlands is found in very small patches in the dry area s near the forests of semi-humid temperate climates. T he only considerable area known to have this type vegetation is in the region of Santiago, Veracruz, on the border with the state o f Hidalgo. Many large cacti al so form part of t he vegetation. The fo llowing species may be mentioned : Agal'esp p. Asclepias linaria Cav. Bo111•ardia longif/ora H 13K. /Judd/cia an·. skutchii Morto n Croton ciliato-glandu/osus Ortega Echinocactus sp. £upatoriwu espiuosamm Gray Junipems.afl'./faccida Schlecht.

Fig.36. The Nolina-Hechtia-Agave desert grows on limestone hills, and often Junipcms is an important element in t he community.

various na mes deri ved fro m the rosette-like arrangement of the leaves : "matorral rosetofilo" a nd "matorral rosetu lifolio". This community h a~ flori stic affinities with the flora of the deserts of central Mexico, sha ring many taxa with the "zona arida hidalguense" and the " zona arida poblana" (Miranda, 1955). The physiognomically domina nt species may vary in different micro-habita ts of the area, but grow together in most cases (Fig.36). The fo llowing species characterize this desert: Dominant species · Agave obscura Schiede Hechtia roseana L.

No/ina parvif/ora (H BK.) HemsI. Other species

Adolph/a infesta HBK. Aneilema karwinskyana (Roem. et Schull.) Wood s.

At·istida barbata F ourn. Aristida glauco (Nees) Walp. Chrysactinla mexicana A. Gray

Bouvardia scabrida Mart. et Gal. Dalea me/antha Schauer Dasylirion acrotriche (Schiede) Zucc. Dyssodia setif/ora (Lag.) Robbins Loeselia glandulosa (Cav.) Don

Km·ll'insk ia humboldt irma (Rocm. c l Schult.) Zucc. Mammillaria celciana Lcm. Mammillaria camptotriclw Dams Myrtil/ucactus geomctrizans (Mart.) Console Notho/aena sinuata (Lag. et Sw .) Kaulf. Opullliasp. Quercus eduanli Trc).

The lowland thorn scrub occurs more abundantly in the northern part o f the state on the border with Tamaulipas. Here, a mixture of this vegetation type and the low thorn selvas generally occurs. In man y cases the thorn scrub appears to be only a secondary stage of the low selvas that have been kept low by an unknown factor (herbivorou s animals?). Up to now I have fo und no other explanation fo r its presence and have included it here because more study is needed to determine whether it should be combined with the low thorn selvas. The following species have been reported in this type : -Bursem simar~~ba (Sw.) Sarg. Capparis incana HBK. Capraria bif/ora L. Condalia mirandana M .C. Johns!. Esenbeckia berlandieri BailI. Karwinskia humboldtiaua (Roem. et Schult.) Zucc.

Nopaleasp. Prosopisjuliflora (Torr.) Cockerell Pithccellobium/fexicau/e (Benth.) Coult. Ra11diasp. Yucca ·trecu/eaua Carr. Zallthoxylumf agara (L.) Sarg.

(17) Swamp vegetation. There are two main types of vegetation in the swamp s : the inland fresh-water swamps and the mangrove swamps that have marine water coming into them. Both types are found in the lowland areas o f the state. (18) Inland swamps. These swamps are f ound in m any scattered areas in Veracruz. Very little is known of their ecology or their floristic composition. The only inland swamps already described are the ones in the sou thern part of the state (Miranda and

A. G6MEZ -POMP A ECOLO GY OF T il E VEGET ATION OF VERAC RUZ

Hcrnitndcz X., 1963 ; Leon C. and Gomez-Pompa, 1970). The soils or these swamps arc inundated the whole year except on their outer border s where they may be free of water for some mont hs in the dry scaso11. Locally these communities have names connected with the local name of the domina nt genus. For exa mple, the Thalia swamps arc called "popales" (Thalia = "popoay"). The species that characterize these swamps arc: Bactri.1· colwue Watts. Cypems J:igm/leus Vahl Cypemsspp.

Eleocharis iuterstiucta (Vahl) R. ct S. Poutederia .mgitafla Pres! Thalia geuiculata L.

The physiognomy of these swamps is derived from the most abundant species and therefo re varies locally.

( 19) Ma11grove swamps. These swamps develop in the coastal lagoons of Veracruz and along many of the rivers (Fig.37). There arc several general reports on the mangrove swamp s of the Veracr uz coast, but the only complete study is the one made by Vazque z (1971) in the Mandi nga lagoon a few miles south of the Port of Veracruz. From this study we get a good picture of the diversity of such swamps in the state. The zonation of the mangrove swamps in Mandinga is very complex because of a

139

combination of ractors , but it follows c~rtain pred ictable patterns. Rhizop!Iora is found most frequently on the exterior border where the wate r level is higher (up to 50 em in Mandinga) nnd where the soils are softer. In n\ore solid soils and sha llower wntcrs A ricennia beco mes predominant, formin g dense comm unities. Mi xed with this mnngrove, Lagwrcularia is fou nd, which becomes very a bundan l in disturbed areas. Conocarpus has not yet been found in Mandinga, but it is known from other swamps in Veracruz. . The roll owing species have been reported from mangrove swamp s in Veracr uz: A••iceuuia germinaus L. Couocarpns erect us L.

Lagunc11/arirt raccmosa {L.} Gacrtn. f. Rhizoplwra mangle L.

Closely_related to the mangrove swamps are o ther swamp forests in Veracruz m areas having a very small amount of saline water (Vazquez, 1971). These are characterized by several species that can live in inundated soils but are more typical of in land types living together with typical aquatic species. The fo llowing species have been reported (Vazquez, 1971) from a swamp of this type; Dominant species Pachira aq11atica Aubl. Other species Acrosticluml aureum L. Amerimt/011 browuii Jacq. Annona glabra L. Avicemtia germi11a11s L. Clerodeudrumligustritlltlll (Jacq.) R. Brown Da/bergia ecastophyllum (L.) Taub. Diospyros digyna Jacq. Ficus iusipida Willd. Hibiscus tiliacetts L.

Laguncularia racemosa (L.) Gacrtn. f. Pithecellobitml dijdfem m Lundell Pithccellobiwu erythrocarpum Standi. Piper uitid11111 Vahl Raudia aculeato L. R/wbdodettia bif/ora (Jacq.J Mucll. Arg. Rhizophom mangle L. Sapiumuitidum (Monac h.) Lundell

{20) Paramo 1·egetation. This is a unique vegetatio n type growing in the highest mounta ins of Veracruz just below the permanent snow belt. There are no ecological studies published from Veracruz, but reports from other high mountains in Mexico may be extrapolated to a certain degree. The most import ant ecological factor at this altitude is low temperature. Very few plants can pass this strong filter. Soils at these altitudes are not well known, and the only profile, made by Johnso n (1970), is shown in Table X. The flora of this alpine vegetation (Fig.38) has been studied by Johnson, and the following species list been· taken from his work : Aspleuium-castaneum Schlecht. et Cham. Cuicus 11iva/is HBK. Drabajorullensis HBK. Draba myosotidioides Hems!. Festucas p. Gnaphalium inornatum DC. Gnaphalium oxypftyllum DC. Fig.37. A mangro ve swamp in M andinga . (After Yazquez , 197 1.)

Gnaphalium popocatepeciauum Sch. Bip. Miiltleubergia sp. Se11ecio chrysactis Sch. Bip. Se11ecio galeottii Hems!. Senecio orizabe11sis Sch. Bip. ex Hems!. Stipasp.

(21) Coastal dunes vegetation. There is a very well develop ed vegetation along the

.... 0

TABLE X 1

SOIL PROFILE 1N THE PARAMO VEGETAT ION OF THE I'ICO DE ORIZARA ( ALTITUDE

Depth

Hori-

(em)

ZOil

Colour when dry

+0-10

+10-20

20-30 30-40

40- 50

50-60

All

A12

Al3 Al3

when wet

Appar. Relar. densiry density

4,250 ~1); TH IS SOIL WAS IDE:-.ITU'IED AS AN ANDO SOIL {CRYPOSAMMf::"T )

Sand

------- ------- - ------· Silr Clay

r?oJ

(%)

Texrure

(%)

-·

~---·----

pH Toral C./o. Org. C/N C. E. C. Allo(1:2.5) N (%) maller (mequiv. / phone (%) (%) JOOg)

-·- -

0· :1::

~ :::: ..,

- --

I OYR 5/1.5 greyish-brown

10YR 3/!.5 very dark greyish-brown

!.27

2.35

89.0

8.8

2.2

sand

5.6

0.093

!.03

2.35

8.5

XXX

10YR 5/ 2 greyish-brown

10YR 3/ 2 very dark greyish-brown

!.37

2.49

87.4

11.4

1.2

sand

6.1

0.060 0.54

!.24

7.4

xxxx

IOYR 5/3 brown

10YR 3/3 dark brown

1.37

2.52

88. 1

10.0

!.9

sand

6.5

0.061

0.52

1.20

7.4

xxxx

10YR 5/3 brown

I OYR 3/3 dark brown

1.37

2.52

84.5

13.0

2.5

medium sandy Ioan1**

6.5

0.070

0.60

1.38

8.4

xxxx

lOYR 5/2 greyish-brown

lOYR 3/2 very dark greyish-brown

1.40

2.52

87.8

10.0

2.2

sand

6.6

0.074

0.59

1.36

8.0

xxxx

lOYR 5.5/2 I OYR 3/2 light very dark brownish-grey greyish-brown

1.53

2.55

87.1

10.9

2.0

sand

6.4

0.055

0.43

0.99

6.9

xxxx

____ ____.

60-70

70-80

10YR 6/1 light grey

++80-90

IOYR 6/1 light grey

*90-100

5YR 6/1 light grey

100-110

RyC

110-120

RyC

120-130

RyC

10YR6/ 2 10YR3/2 light very dark brownish-grey greyish-brown

1.60

2.56

86.6

12.5

0.9

sand

6.4

0.032 0.30

0.69

5.3

xxxx

lOYR 3/1 very dark grey

1.72

2.59

89.0

10.1

0.9

sand

6.2

0.012

0.08

0.19

3.1

xxxx

JOYR 3/ l very dark grey

1.73

2.58

88.3

9.8

1.9

sand

6.3

0.010 0.06

0.14

2.2

XXX

lOYR 3/1 • very dark grey

1.68

2.59

87.6

12.0

0.4

sand .

6.5

0.012

0.07

0.15

2.2

XXX

5YR 6/1 light grey

5YR2/2 dark reddish-brown

1.68

2.60

87.6

12.0

0.4

sand

6.4

0.010

0.03

0.07

1.8

XXX

5YR 6/ 1 light grey

5YR 2/2 dark reddish-brown

1.73

2.59

87.2

12.0

0.8

sand

6.4

0.010 0.03

0.06

2.0

XK X

5YR2/2 dark reddish,brown

1.71

5YR 6/ 1 light grey

8t-

't)

2.59

87.6

11.6

0.8

sand

6.4

0.010

0.01

0.02

2.0

XXX

'After J ohnson (1970). • . +dense roots; ++lowest limit of roots between 60 and 96 em; * coldest laye•; •• very coarse sand: 5.6 %; coarse sand: 5.4-8.6 % ; medium sand: 9.7-16.7%; fine sand : 27.1-31.4%; very fine sand : 24.5-32.7%.

-l :l: m

< rn C)

g 0

z 0

'Tl

,.rn<

,.c>

()

1 142

A. GOM EZ-POM PA

ECOLOGY OF T HE VEGETAT ION OF VERACRUZ

143

coasta l dunes and beaches. This pioneer vegetat ion has been studied by Sauer (1967) and by Vazquez (197 1). The profile shown in Fig.39 is taken fro m the firs t author. The followi ng species are characterist ic of this vegetation type: Amcia .>plwerocep/wla Schlecht. ct Cham. Amarwu/ws gregii S. Wats. Andropogcm g/omera111s (Walt.) BSP. Andropogon litom/is Nash Bidens sqrwrrosa H ll K. Cakile lwrceo/ma 0. E. Schulz Ccmava!iamaritima (Aubl.) Thou. Casearianitida (L.) Jacq. Clmia c/wnraecri;·Joides Collad. Ctmia cinerea Cham. ct Schlecht. Cfrr)•soha!mtus icaco L. Cnidoscrdus frerbacwus (L.) Johnston Coccoloba uo•ifera L. Comme!ina erect a L. Crossopetcrfrmr !aJifolium Sw. Croton ptmctatus Jacq. Cyperus articulatus L. C)•perus /igu/aris L. Eragr-osti.1· damingensi.r (Pcrs.) Steud. Euplrorbicr buxifo/ia (Lam.) Small. Fimbristy!is spat!racea Roth Ipomoea pe;·-caprae (L.) Sweet Ipomoea .tto!onifera (Cyrill.) Po ir. Iva asperifo/ia Less.

Island vegetatio n is closely related to the vegetatio n in sand dunes, because most of the islands in the state do not have well-developed soi ls. The only island studied in detail up to now is the Isla Verde in front of the port of Veracruz where the diagram of Fig.40 was made (Lot, 1971). The foll owing species have been reported from this Island:

Fig.38. A view of the paramo vegetation at the Pico de Orizaba . (After Johnson, 1970.)

j GULF

10m

CLEARING

-~ ~

Jc1cquinia prmgens A. Gray Merremicr c/ircoidesperma Donn. Smith Nectcmc/ra cvricrcea (Sw.) Griscb. Oenot/rera drummonclii Hook. Ot/wke /indenii Bush Okenicr lrypogaea Schlecht. ct Cham. Opuntia dillenii (Ker-Gaw.) Haw. Pcr!afoxiatexalt(l DC. Pwricrmr repens L. Paspalum o•aginalum Sw. Pfry/a nodiflom (L.) Greene Pouteria dur/(llrdii (Standi.) Aubr. Psyclrotria nutans Sw. Randia acu!ea/a L. Raudia/aeleo•irens Standi. Sesuviw11 parlulacastrrrm L. Sporobolus virginicus (L.) Klmth Scaeo•ola plumierii (L.) Vahl Spartinapatens(Ait.) Muhl. Slemodia tomentosa (Willd.) Gray et Torrey Ut~io/a paniculala L. Verbesina o/it>acea Klatt Zamicrjinfuracea L.

;.; !,:{,g,.,#:-6~0

(!im,,,..,,;•.

Cassia chomaecr istoides· · · · · • Oenothero drummondii· ·· ···· •

Sport ina patens····· ·· ······ ·•

Uniolo paniculoto · ·· ··· ··· ·· ··•

1pomoeo ·pes-coproe - ..... · . · · •

Conavolio ma rit ima ·· ··· ·· ... ·• Coccoloba uvilera····· ........ · Chrysobalo nus icc co..... . ...... ·· - -· · ..- - - - - - - - - - - - - - - Ra ndle ocu leato· · ········ · · · ············ •·· ··· • ······• ···- ····· ·· ·• ·······Crossopetolu m latilollum- ... · · · · · · · · · · · · .. .... . .. .. . · ··· - -Nectondra corloceo-·· .•••.... · ··· ·•····· · ······ · • ····• ········ - ······Psychotria .nutons··· ....•.... · · · · · . ·. · · · · · · · · · · · · ...... . •.... · · . ... ··• Gliricid io seplum··· . ·. · · . . · · · .. · . .. · .... .. · · .. .. .... . · ·· ...... ..... .•.....••. ... ... . .. .. . . .... .

Fig.39. Vegetation profile of coastal dunes vegetation (north of Tuxpan). (After Sauer, 1967.)

Agave sp. Allanumda catlwrtica L. Ambrosia cumanensis H BK. Antigonon /eptopus Hook. et Arn. Balis maritima L. Caesalpinia bonduc (L.) Roxb. Canovaliamaritima (A ubi.) Thou. Cframaesyce buxifo/ia (Lam.) Small Cit!rarexylum e/!iplicum Sesse et Moe. Crota/aria spp. Eragrostis domingensis (Pers.) Steud. Fimbrisly/is spaJiwcea Roth Hymenocallis spp. Ipomoea stolonifera J. F. Gmel. ipomoea pes-cap rae (L.) Sweet

Iresine celosioides L. Jacquinia aura/Ciiaca Ait. Lagwrcularia racemosa (L.) Gaertn. f. Merremia discoidesperma Donn. Smith Nerium oleander L. Pandanus sp. Pauicrmr repens L. Plumeria acutifo/ia Poir. Raudia laelevirens Standi. Sesuvium porlulacas/rum L. Scaevo/a p/wnierii (L.) Vahl Suriano maritima L. Terminalia catappa L. Tournefortiagnapha!odes R. Br.

{22} Aquatic vegetation types. It is difficult to distinguis h this vegetation type from other types. M any of those mentioned before may be included in here, but since we

144

A. G6MEZ-POMPA

ECOLOG Y OF THE VEGETATION OF VERACRUZ

.!!

0<:

" ;;;

"" ;g 0

'5 t0

E :,,

. il

E .2

~ 0

" "'"'

·t

<>.

·o ....

., ~

" <>

a. 0

._ c: "' ;;;"

•

· .!'!

" ~

·;; ~

t0" a.

._c:

145

into the same type, the dillerent names being applied to differen t floris tic compositions. _ Jn these "grasslands" higher plants are the most important constituents, but a few algae also make an important contribut ion to the ecological mosaic of these "grasslands". l n Fig.41 a profile of the relations of these different organisms in the different coral reeflagoons in Veracruz can be seen. The following plant species have been found in this vegetation type: Halodule wrightii Ascherson Ha/ophila decipiens var. pubcscens Hartog Ruppia maritima L.

Syringodium[ilijorme Kutzing Tlw/assia testudinum Koen ig ct Sims

Other aquatic vegetation types. In the Lagu na de Mandinga, Vazquez (1971) attempted to classify the aq uatic vegetation by dividing it into four groups: (J) vegetation with S\V

35m

plants fixed to the soil but wit h aerial parts; (2) vegetation composed of species with float ing leaves; (3) vegetation composed of plants with submerged leaves; and (4) free floating vegetation, not fixed in the soil. As constituents of the first group the followi ng species are mentioned:

Fig. 40. Vegetation profile oflsla Verde. (After Lot, 1971.)

lack a general study of the aquatic vegetation of Veracruz, we have not attempted to make a precise classification, bu t only to include some aquatic vegetation types not yet mentioned that are of special ecological interest.

. Marine vegetation. Several marine vegetation types have been recognized in coral reefs (Lot, 1971) by the name marine "grassland" or "ceibadales". In fact they all fall Al gae

Phonerogomoe

Halimeda opuntla

species of Caulerpa

Ha/odule wright//

;

Rhipocephalus phoenix

Cymapol/a b orbalo

Padfna varicgo t a

Crinum erubescens A it Echinolaena polystachya (HBK.) Hitch. E/eoclwris clegans (HBK.) Roem. et Schult. E/coclwris mutata (L.) Roem. et Schult.

Linmoclwris/fava (L.) Buchenau Pontederia sagitalla Prest Sagillaria lancifolia L. 'l)•plw angustifolia L.

In the second group these species are mentioned: Nymphaea amp/a (Salisb.) DC.

Nymplwea blanda G. Meyer

Of the third type these species a re menti oned : Cabombasp. Ccratophyllum demcrsw11 L.

Najas guada/upc11sis (Spreng.) Morong Ruppia marilima L.

These species arc mentioned as composi ng the free floating vegetation: Bacopa mo11ie1·i (L.) Wittst.

Pistia stratiotes L.

Thalassia testudlnum

Secondar y vegetation

50 Metr e s

Fig.41. Profile of a coral reef showing the distribution of the species. (After Lot, 1971.)

I have included secondary vegetation as a different type so that I may discuss it and not because I consider it a truly distinguishable vegetation type. There is, up to now, no classification available for typical second-growth vegetation. The reason is that it is the most complicated and variable grouping of species that can be found in any area, and i t varies from place to place as well as from time to time. The principal factor producing secondary vegetation is man and his activities in agriculture, cattle, and fo restry. Another problem with secondary vegetation is that there are no proven methods available to study it in a coherent manner. The only

146

A. G 6 M EZ-POMPA ECOLOG Y OF T HE VEGET ATION OF VERACRUZ

atte mpt to do so has been the method used in the ecological survey of the lowlands of the Gulf o f M exico (Mira nda ct al. , 1967). From this work we have a large amoun t of data abo ut the presence of certain species in ~ilferent stages of d ist urbance in an area wit h a known vegetation type and soil. In this survey the first papers includ ing data from secondary vegetation appear (Anonymo us, 1960/ 1969; G omez-Pom pa ct al. , 1964a, b; Sousa, 1964; Sarukhfm, 1964). This work is discussed here because some of the data from tha t survey and from ihe p u blications derived from it are from: or applicable to localities in Veracruz. Unfortuna tely, the area covered by these earlier studies did not cover the whole sta te o f Veracruz, and almost no informat ion was obtained from a ltitudes higher than 1,000 m and dlier than 1,500 mm of precipitation. In more recent studies on seconda ry vegetation (Gomez-Pompa, 1971), the classification scheme has been broadened to incorpo rate more variables that can be studied experimen tally. To present a list of the different · species in secondary vegetation derived from differen t vegetation types in the different regions could be a goal for a future paper, b ut here I can only present a list of the genera which are basically represente d by secondary species .in Veracruz: Apeiba Artilrostemma Argemone Antigonon Alibcrtia Amorrmthus k·istolochia Asclepias Ailws Aster /)_cal;•pha Adelia Andropogon Acacia Aescltynomene Anoda Bixa Bromelia Bauhinia Bunclwsia Borrcria Byffneria Belotia Cydista Cordia Canna Cleo me Cochlospermum Combrctum Commclina Calea

Conyza Cirsium Carex Cypems Cnidosculus Croton Casearia Callirmdra Cenchms Canavalia Cassia Centrosema Crotalaria Cuphea C/idemia Conostegia Ccdrela Cissampelos Cecropia Cmsea CardiospermUI/1 Cestrum Cost us Chenopodium Davilla Dioscorea Dalea Desmodium Eupatorium Euphorbia Eragrostis

EriosenliJ Erythrina Eugenia Ficus Gono lobus Gliricidia Gouania Guozuma Hamelia Heliconia Hyptis Hoffmania Hibiscus Heliocarpus ·Indigo/era Inga Ipomoea Iresine Jatropha fii iiCliS

Kallstroemia Lasiacis Lonchocarpus Lygodium Luehea Linaria Lantana Lippia Maranta M arsdenia Melampodium

Mikania Momordica Muntingia Mimosa Mucuna Malache Malvaviscus Miconia Melochia Myriocarpa Neurolaena Ochroma 0 /;•ra

Oxa/is Perrolletia Parthcnium Porophyllum Plettraltfhodeltdrolt Ptmicum Paspalum Phaseolus Pithecellobium Psidium Pisonia Passiflora

J!e.JiJ1e.J'itl

Pilyto/acca Piper Po/ygu/a Pa/icourea l'syclwtria Picramnia Physalis Pilea Phyla Rolliuia RueIlia Raull'o/jia Rvurea Rhyuchosia Ril ina Rvmleletia Russelia Se1jania Sesuvium Schoepjia Scleria Sida Smilax 1

147

Solanum Spoudias Stacl!ytarplteta Stemmadenia Stigmapltyl/on Taberuaemontmw Tecoma Toumefortia TnjJOKtmdm Trophis Tithonia Turbina Tetracera Teucrium Tibouchiua Triumfetta Trema Urem Verbesina Vismia Vemonia Wissaclu/a Xant/wsoma Zomia

References Aguilera, N ., 1958. Suelos. In : Los Recm:.'iOS naturales del Sureste y su Aprovec!tam ieuto, 2. Edic. Inst. Mex. Rcc. Nat. Renov., Mexico City, pp.l77-212. Anonymous , 1960/ 1969. Informes de Ia Comisi6n de £studios sobre Ia Eco/ogia de Dioscoreas. Tnst. N ac. Inves t. Forcstales, Mexico, Mexico City, 5 vel. Balls, E. K., 1939. Plant hunting in Mexico. Card. Citron., 3 ( 105): 122-123;138-:139;1_52153. . Baynton, H. W., 1968. The ecology of an elfin fo rest in Puerto Rico, 2. The mtcrochmate ofP1co del Oeste. J. Amold Arboretum, 49:419-430. · Beard, J. S., 1953. The savanna vegetation of northern tropical ~m~rica. Eco/. Mon~g!·. , 23 :149-215. Chiang, F., 1970. La Vegetacion de Cordoba, Ver. Thesis Fnc. Ctcncias~ UNA~, Mextco, 47 pp. Cuanalo, H. and Aguilera, N., 1970. Los suelos de Ia cuenca mtermedm del RIO Papaloapan. Pub!. Esp. Inst. 1111•. Nac.For. Mex., 6:1-62. Garcia, E., 1970. Los eli mas del estado de Veracruz. Anates lnst. Bioi. Univ. Nac. Mex., Ser. Bot., 41 . (1):3-42. Gentry, H . S., 1942. Rio Mayo plants. Camegie l nst. Wash., Pub/., 527 :t-328. Gentry, H. S., 1946. Sierra Tacuicham ona-a Sina loa plant locale. Bull. Torrey Bot. C/ub,73(4):3 56362. Gomez-Pom pa, A., 1965. La vegetacion de Mexico. Bot. Soc. Bot. Mex.,29:76-J20.. Gomez-Pom pa, A., 1966. £studios bottinicos en/a Region de Misantla, Veracmz. Ed1c. In st. Mex. Rec. Na t. Renov., Mexico, Mexico City, I 73 pp. Gomez-Pom pa, A., 1967. Some problems of tropical plant ecology. J. Arnold Arboretum, 48(2):104121. 'cal Gomez-Pom pa, A., 1971. Posible papel de Ja vegetacion secundaria en 1a evolucion d e Ia J1 ·ora trop1 · Biotropica, 3: 125-135. Gomez-Pom pa, A., VlUquez Soto, J. and Sarukhan, J., 1964a. Estudios ecol6gicos en las zonas tropicales calido humedas de Mexico. Pub/. Esp. Inst. Nac. lnv. For. Mex., 3:1-36.

14S

A. GOM EZ-POMPA

Gomcz-Pom ra, A., Hcrmindcz. P., L. and Sousa, S. M., l%4b. Es!udio fi!occoltigico de Ia cuenca in1crmedi:1 del Rio Papaloapan. Pub/. Esp. Ins/. Nac. !111·. For. Mh·., 3:37- 90. Gomez-Po m pa, A. and Ncvling, L. 1., 1970. La llora de Veracruz. Anales Ins/. Bioi. Uni••. Nac. lv/i!x., Ser. 13oL, 4 1( 1) : 1-2. Howard, R. A., 1968. The ecology of an elfin fo rest in l'tiCrlo Rico, I. ln!mduction and composition studies. J. Amold Arboretum, 49(4):38 1-41 &. Ja nzen, D. H., 1970. Jacquiuia fi/1/I.!feus, a heliophilc from the understory of tropical d eciduous forest. Biotropica, 2(2): 11 2- 119. Johnson, E. L., 1970. Mmfogcucsis y Clasifrcacivu de Algunos perfiles de Suelos deril•tulos de Ceuizas volcanicas del Pica de Orizaba, Puebla y Veracruz. Thesis Fac. Ciencias, UN AM, Mexico, 78 pp. leon, C. J . and Gomez-Pom pa. A., 1970 . La vcgelacion del surcstc de Veracruz. Pub/. Esp. lust. Nac. btv. For. Mex., 5:15-48. Lol, A., 1971. Estudios sobre fancr6gamas marinas en las ccrcanias de Veracruz, Ver. Anales Ins/. Bioi. Unil•. Nac. Mi:x., Ser. Bot., 4 2 (1): 1-48. Lundell, C. L., 1937. The vegetation of Pclen. Camegie lust. Wash. , Pub/.,478: 1- 244. Miranda, F., 1955. Fonnas de vida vcgelales y el problema de Ia delimitaci6n de las zonas aridas de Mexico. In: M esas lledonda.\· sabre Problema.,· de las Zonas tiridas de Mexico. Edic. lnst. Mex. R ec. Nat. Renov., Mexico City, pp.85-1 19. Miranda, F ., 1959. Posible significaci6n del porcentajc de gcneros bicontincnla les en America tropical. Anales lmt. Bioi. Unh•. Nac. Mex., 30: 117- 150. Miranda, F. and H ernandez X., E., 1963. Los lipos de vegelacion de Mexico y su clasificaci6n . Bot. Soc. B ot. Mh:., 28:29-179. Miranda, F. and Sharp, A. J., 1950. Characlerislics of !he vegetal ion in certain temperate regio ns of eastern Mexico. Ecology, 31 :313-333. Miranda, F., G6mez-Pom pa, A. and Hernandez, X., E., 1967. Un metoda para Ia invesligaci6n ecol6gica de las rcgioncs lropicales. Ana/es lnst. Bioi. Univ. Nac. Mex. , Ser. Bot., 38 ( 1):101-110. Mohr, E. C. J. and Van Baren, F. A., 1954. Tropical Soils. Interscience, Londqn, 498 pp. Mosii\o, A. P. and Garcm, E., 1966. Evaluaci6n de Ia sequia in!racstival en Ia Republica Mexicana. Uni6 n Geognifica lnlcrnaciona l. Confc rencia Regional Lal inoamerican a . Edic. Soc. ·Mex. Geogr. Estat!is., 3:500-516. Pennington, R. D. and Sarukh{m, J., 1968. Arboles tropica/es de M exico. lost. Nac. Invest. Forestales, Mexico, Mexico City, 413 pp. Ramos, C., 1971. Vegetacion de Ia Zona arida Veracmzana. Thesi; Fac. Ciencias, UNAM, Mexico, Mexico City, 30 pp. Rzedowski, J ., 1963. El exlremo boreal del bosque tropical siempre verde en Norteameric a Conlinenlal. Vegetatio, 11(4):173-198. Rzedowski, J. and McVaugh, R., 1966. La vege1aci6n de Nueva Galicia. Coutrib. Uni••. Mich. Herb., 9(1): 1- 123. Saru khan, J., 1964. Estudio succsional de un area talada en Tuxlepcc, Oax. Pub/. Esp. l ust. Nac. !nv. For. Mex., 3:107-172. Sauer, J., 1967. Geographic reconnaissan ce of seashore vegetation along the Mexican Gulf coast. Coastal Stud. Inst., La. State Univ., Tech. Rep., 56:59 pp. Solo, M., 1969. Consideraciones ecoclimliticas del Estado de Veracmz. Thesis Fac. Ciencias, UNAM, Mexico, Mexico City; 43 pp. Sousa, S. M., 1964. Estudio de Ia vegetaci6n secundaria en Ia region de Tuxtepec, Oax. Pub/. Esp. Just. Nac. !nv. For. Mex., 3:91-105. Sousa, S. M ., 1968. Ecologia de las leguminosas de Los Tuxtlas, Veracruz. Aua!es Just. Bio i. Uuiv. Nac. M ex., Ser. Bot., 39(1):121-160. T o ledo, V., 1969. Diversit!ad de £species en/as Se/vas altas de Ia Platticie Costera del Golfo de Mexico. Thesis F ac. Ciencias, UNAM, Mexico, Mexico City, 55 pp. Vazquez, C., 1971. La vegetaci6n de Ia laguna de Mandinga, Veracruz. Anates !nsf. Bioi. Univ. Nac. Mex., Ser. Bot., 42:49-94. Whiteside, E. P., 1960. Observations 011 Great Soil Groups in Humid Tropical Portions of Mexico. Rockefeller Found., Mexico (unpublished ). W illia ms, L. L., 1939. Arboles y arbustos del Istmo de Tehuantepec , Mexico, Lil/oa 4:137-171.

Chapter 5

The Phytogeography and Vegetation of Chiapas (Mexico) DENNIS E. DREEDLOV E Department of /Jot any, Cali}imtia Academ y of Sciences, San Francisco, Calif. (U.S.A.)

Summary Chiapas has one of the most diverse and la rgest flo ras of any of the Mexican states. The study of this vegetatio n is facilitated by reference to the seven physiographic regions outlined by Mulleried (1957). These regions have consistently sim ilar fl oristic association s. Th1 ee of these regions, the Central H ighlands, the Central Depression and the Northern Highlands , are restricted to Chiapas. T he Sierra Madre a nd the Eastern H ighlands extend southward into Guatemala while the P acific and Gulf Coastal Plains are southern extensions of large central Mexican regions. T he result is that many of the floristic associations i11 Chiapas are unique without wiclespread relationships. The classification of the vegetationa l formations of tropical America establi shed by Beard (1944) is remarkably adequate for t he vegetation ofChiapas . Some adjustment is necessary to account for the temperate forests of the Central Highlands and the Sierra Madre. T here are nineteen fo rmations described in this work and they are arranged into five formation series. The four optimum formations are characterized by a climate in which significant rain falls in every month of the year and a well drained substrate. The six seasonal formations also occur on well drained soils. .The climate, however, is marked by a distinct dry season of 2-6 months. The wet-land forest a nd treeless fo rmations are much less natural groups. T hey are in general narrowly restricted in distributio n and dependent on some special feature of the environme nt. The dominant and most common species of trees and shrubs are listed for each formation. Second growth formations are common and very d iverse, and one example of t hese is described.

Introduction Chiapas is the southernm ost state of Mexico, situated on the Pacific Coast between the Guatemala border and the Isthmus of Tehuantep ec, and occupying more than 74,000 sq. km. The present population of Chiapas is near 1,500,000, with almost one half of this total being Mayan agriculturalists living in dispersed hamlets. The climate is diverse, ranging from semi-desert to rainforest and fr om sea-level with stands of

150

D. E. DREEDLOVE

PIIYTOG EOGRAP HY AND VEGETA TION O F C HTAPAS (M EXICO)

mangroves to peaks as high as 4,000 111 with sHb-alpinc vegetat ion. There arc over 8,000 species of "f'ascular plants recorded from the state. The annual rainfall varies from under 800 mm in some localities to over 3,500 mm in others. ll is impossib le to estimate the percent of endemism for the state as a whole but there arc several areas in which local endemism is q uite high.

Phytogeography of Chiapas Following Mulleried (1957), Chiapas can be divided into seven physiogr aphic regions (see map, Fig. !). Florist ic associations within one of these regions are more similar to each other than the same floristic associations from two different physiographic regions. That is to say, two pine-oak forest communities from the same region are more alike than two pine-oak forest communities from two different regions. For this reason, the vegetational associations are best studied region by region, even though

..... ·\' f.

()

' ~

(•

•"-·-·-·-·-··-·-·-·-· j j

·..

P HYS J:OGRA PHJ:C REGJ:O NS OF CHJ:AP AS

Fig.I. Map of Chiapas with the physiogra phic regions outlined.

151

there will be an overlap of plant associations. Many local endemics a1e restricted to a particular plant association with in a particular physiograph ic region. The regions and the plant associations fo und with in them arc: (/)The Pacific Coastal Plain- a narrow strip of metamo rph ic strata and intrusive rocks of Precambrian and Paleozoic age with several ranges of low hills. This region is flat and relatively dry in the north and hilly and wet in the south. Mangrov e swamps (a) with patches or coastal strand (b), fo rm a continuo us band along the Pacific Ocean. Tropical deciduous ro,:esl (c), palm fo rest (d), thorn woodland (e) , and shorttree savanna (/), are all quite common in the remaining inland areas. Evergree n and semi-evergreen seasonal fo rest (g) is fo und most abundan tly in the south. The plant associations found in th is region arc widespread types sca!lered along the Pacific Coast from Si na loa to Panama (Stand ley, J940). T here appear to be very few e ndemic species. (2) The Sierra Madre de Chiapas, which is parallel to the coast from the southern end of the Isth mus of Teh uantepec extending through Chiapas into Guatema la, is a narrow steep range of volcanic mountains ranging in elevation from I,500 m in the north to 4,000 m on the Guatem ala bord er. (a) Tropical deciduous fores t is common at lower elevations on both escarpments especially in the north, whereas (b) evergreen and semi-evergreen seasonal forest is restricted to riparian situation s in the north and middle elevations of both escarpments. (c) Lower montane rain forest is found only on the lower slopes of Volcan Tacana in the Soconusco district. Most of this Pacific rainforest has been destroyed or altered for cultivation of coffee. (d) Pi ne-oak forest is widespread at middle and higher elevation s in the north. It is replaced by (e) pine-oakLiquidambar forest, (f) montane rain forest, and (g) evergreen cloud· forest in the south. T here are many local endemics in t his region, especiall y in t he higher-el evation associations about Yolcim Tacana. Arclisia oJ•andensis Lundell, Buddteia o1·andensis Lundell, Clethra matudai Lundell, Deherainia matudai Lundell, Eugenia siltepecana Lundell, Quercus ovandensis Matuda, Quercus paxtalensis C. H. Muller, Symplocos tacanensis Lundell, and Z inowiewia matudai Lundell are a few of the conspicuous endem ic species. (3) The Central Depression (Valle Central: Helbig, 1964a, b; Depresi6 n Central: Miranda, 1952; Rzedowski, 1965). Beginning with the fast m oving streams flowing out of the Cuchumatan Massif, the Rio Grijalva descends slowly through a broad terraced valley from I,200 m at the Guatemala border to 500 m at the mouth of El Sumidero. This giant· basin is characterized by a dry climate (in some places, less than 800 mm annual rainfall). The strata are most ly marine limestones and slates. The depression terminates abruptly as the Grijalva flows into El Sumidero, a sheer faced canyon with walls up to 1000 m high. This dry valley(Contreras Arias,l955, refers to this area as semi-arid) is more than 200 km long and up to 70 km br oad . It is complete ly surrounded by moist, densely forested mountain areas, affording it complete isolation from other pockets of xeric vegetation. Quite understandably there are a large number

t52

D. E. BR EEDLOVE

PIWTOG EOGRA PH Y AND VEGETATION OF CHIAPAS (MEXICO)

of endemic plants, especially a mong the sh rubs and small trees occurring on dry, exposed slopes. Catoplieria chiapensis Gray, Erytllrina goldmanii Standley, Lop11zia /angmaniae Miranda, and Wimmeria acuminata L. Williams arc particularly conspicuou s endemics. · The flora of the Central Depression, although dry, and containing a number of Central Mexica n elements, has a st riking number of species from the d ry flora of Oaxaca completely missing, even though some of these species occur in the dry regions of eastern Guatemala (Ampllipterygium adstringe11s (Schlecht.) Schiede, Apoplanesia panicu/ata Pres!, Megastigma, Myrtillocactus, a nd Plocosperma). Another interesting facet of the flora of this regio n is the occurrence of many species known elsewhere only from t he dry regions of the Yucatan peninsula (Miranda, 1952; Clusia flm•a Jacq., Coccoloba cozumelensis Hems!., Dioon spinulosum Dyer, Guaiacum sanctum L., Guettarda combsii Urban, GJ'mnopodium antigonoides ( Rob.) Blake). Most of the valley was probably originally covered with (a) tropical decid u ~us forest; however, extensive cultivation and grazing has Jed to large tracts of (b) thorn wood l~nd , and (c) savanna. In certai n protected riparian areas, (d) everg reen and semi-evergreen seasonal fores t occurs, a nd (e) palm forest is CO!nmon o n alluvial flats in t he southe1 n end of the depression. (4) T he Chiapas Plateau (also commonly referred to as the Central H ighlands (Vogt, 1969), La Meseta Central de Ch iapas (Miranda, 1952) and Chiapas H ighlands (Goldman and Moore, 1945). A highland mass, about 220 km along its principal axis and from 50 to 100 km in width lies directly east of the Central Depression. It is composed mostly of marine limestones with extrusions of volcanic rocks on the higher peaks. The broad summit is from 2, 100 to 2,500 m in elevation with a few peaks reaching as high as 2,900 m. There is a mat ked d iffere nce in the rainfall between the east and the west escarpments and the vegetation reflects this difference. Tropical deciduous fo rest (a) and pine-oak forest (b) occu r on the drier west side, bordering the Central Depression. Pine-oak-Liquidambar (c) and montane rain forest (d) covel the eastern escarpment. The summits and eastern slopes of the higher peaks and ridges have a diverse evergreen cloud forest (e) which contains a large number of endemic species : Carex chiapensis F. 1. Hermann, Eugenia ravenii Lundell, Eugenia tonii Lundell, Hida/goa breed!ol•ei Sherif, Magnolia sharpii Miranda, Miconia ravenii Wurdack, Parathesis breedlo1•ei Lundell, Sah>ia querceto-pinorum Epl. and Jat. , and Symp!ocos exce/sa L. Wms. are a few of the more conspicuous ones. Another large group of species is restricted to t his region and the limestone areas of Huehuetenango, Alta Verapazand Baja Verapaz, Guatemala. This area supports a large population of Mayan-swidden agriculturalists. The 1960 census estimates the populatio n size conservatively between 250,000 and 300,000. T hese people live in a dispersed "vacant town" manner and cultivate most of the arable land available in t his region. As a result, very little primary forest is left. (5) Eastern Highlands. Eastward from the Central Plateau, thete are several ranges of steep mountains gradually sloping off into the drainage of the Rio Usuma-

cinta. The area is mostly limestone with some sandstone and volcanic extrusions. It ranges in elevation from 400 to 1500 m. The vegetatio n is for the most part uniform with lower mont ane rain fores t (a) being most common. T here are, however, patches of short-tree savanna (b) and pafm forest (c) scattered throughout the area. Everg reen and semi-evergreen seasonal fo rest (d) is com mon in d ryer situations in the northern portion of the area. Tropical rain fores t (e) is present in the flat areas surround ing the u pper drainage of the Rio Usumacinta . Monta ne rain forest (f) is present only on the crests of the highest ridges. In contrast to the Central Plateau, this area is very sparsely populated and large tracts of virgin forest remain. The florist ic associations present here are continuous with associations in the Peten 1egion of Guatemala, and the two areas taken together contain many endemic taxa. (6) T he Northern Highlands. To the north of the Central Plateau and the Central D epression, lies a series of steep ranges of volcanic origin but geologically quite complex. The chasm of the Rio Grijalva traverses this area with steep faced cliffs and high ridges on both ·sides. This area is bounded to the north and northwest by an extension of the Sierra Mad re which lies across the border in Oaxaca. Lower montane rain forest (a) occu rs along the bases of the ranges while montane rain forest {b) is common o n the higher ridges. Pine-oak-Liquidambar and evergreen and semievergreen seasonal forest (c) are comm on in drier sit uations in temperate and lowland areas, respectively. This region has no major~popul a tion centers and few roads; much of it can only be reached by fo otpat hs. It is quite understandably the most poorly k nown of the physiographic regions. (7) The Gulf Coastal Plain. Two small segments of this large physiographic region a re found in the northeast corner of Chiapas. The vegetation is mostly secon d growth f rom what once was t ropical rain forest (a) or evergreen and semi-evergreen seaso na l forest (b), but now is short-tree savanna (c) and second-growth tropical forest with scattered palm fo rests (d). Lundell (1942) and Williams (1938, 1939) discuss the p la nts of part of this area. Perhaps the most striking aspect of the Chiapas flora is the fact that most of the area of the state is contained within nart:owly restricted physiographic areas. This alone accounts for the large n umber o f taxa endemic to the state. Only two smal! portions of the state contain floristic associations which are closely related to similar associations in tile rest of Mexico. Both the Gulf Coastal Plain and the Pacific Coastal Plain have their vegetational associations continuously linked far to the north. Two other physiographic areas (the Sierra Madre and the Eastern Highlands) along with their vegetational associations extend to the south into Guatemala and El Salvador and are strictly Central American in aspect. The remaining three areas (the Northern H ighlands, t he Central Depression and the Central Plateau) are strictly C hiapas phenomena. The fl ora, therefore, although having elements of both Central Mexico and Central America, has an aspect quite its own.

!53

154

D. E. llREEDLOVE

PH YTOGEOGR APHY AND VEGETATION OF CHIAPAS (MEXI CO)

Vegetational formations of Chiapas The classification of the vegeta tional formations used in this account is strongly patterned afte r the one established by Deard (1944). Certain modification s a nd additions have been made in o rder to better describe the formations as t hey occu r in Chiapas. None of the available treatments of vegetation types o f Mexico which are applicable to Chiapa~ (Miranda, 1952 ; Miranda and Hernandez X., 1963; Wagner, 1964 ; Gomez Pompa, 1965 ; Pennington and Sarukhan, 1968) adequately take in to account Beard 's Fo rmatio n Series concept. This concept is essential to the classification presented here and it is felt that it g ives the simplest, most easily un derstood terminology for the tropical forest types of Chiapas. Where it is possible and clearly understanda ble, the forest types referred to by other authors for Chiapas a re listed after the appropriate formations. The form ations of Chiapas are arranged into fo ur formation-series and are listed diagrammat ically (Fig.2). Second-grow th fo rmations will be discussed briefly at the efi{j. Optimum formatiom occur on well-drained lands and have a habitat characterized by significant preci pitation in every month of the year. The four formati ons in this series can be arranged on an altitudinal grad ient from 300 to 3,500 111 and have broad areas of intergradatio n between them. Seasonal formations also occur on weli-

I I

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I es£AS0N AL FORMATION S

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I eRUTRICTED fiORMATIONS • TilUI.fSS fOitMATIOHS PAU.MO

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Description of the formations

T hese fo ur formatio ns are all quite similar physiognomi cally, being composed of many layers of evergreen trees a nd having abundant epiphytes and !ian as. A dry season is absent or at most only a few weeks i n length and the forest floor never dries out. Deciduous leaved trees are quite uncommon and mostly occur in the zones o f intergradation with Seasonal formatio ns. B etween orie fi fth and o ne fourth of the forest a rea of Chiapas is covered with an Opt imum formation .

---..!...__ --- ._L_________ _

J-~===-:

3000

d rained la nds bu t have a habitat characterized by alternate wet and dry seasons with the dry peri od lasting between 2 a11d 6 mont hs. The fo ur lowland for mations in this series can be arra nged on a gradient o f increasing arid ity and broad areas of intermediate forests occur. The two highland formations are also in response to greater aridity. T he remaining two formation-se ries arc admittedly artificial groupings, made for the sake of conveni.ence, and sharing only physiognom y in t!1e case of the treeless formations and standing water in the wet-land forest fo rmations. The formations within these series have litt le or no no ristic relationships and a re for the most part quite locally distributed and. dependen t on some special feat ure of the environ ment.

Optimum formations

e OPTI MUM FORMATIONS

!55

•VI'ULANO fOil Sf f OIMAttOHS UMPUtAU I *'AI.IAN fOifSf SWAII\P & lOWlAND II:IPAJt iAN ,OII:ESJ

PAlM FOilU r

COASTAl SlllANO

Fig.2. Diagrammatic representation of the vegetational formations of Chiapas.

{!) Tropical rain forest . (Selva Alta Siempre Verde in part : Miranda, 1952, 1957 ; Selva Alta Perenn ifolia in part: Miranda and Hernandez X ., 1963 ; Gomez Pompa, 1965; Pennington and Sarukhan, 1968.) Only in a few locations in the valleys bordering the Rio U sumacinta does a forest occur of t he proportions great enough to be called tropical rain forest. Here the forest is t hree-storied with the uppermost story composed of t rees with straight, unbranched, buttressed trunks ri sing as much as 50- 60111 from the forest fl oor (Miranda, 1961). The second story forms a continuous canopy and is between 25 and 40 m tall. The third story is composed of branched small trees from 10 to 20m tall. Small sh rubs and herbaceous cover are p ractically absen t and epiphytes are only in the up per stories. T hese forests are completely surrounded by lower montane rain fo rest, and intergrade into it. Some of the most common canopy trees include : AJpidosperma megalocarpon Muell. Arg., Brosimum a!icastrum Sw., Dialiwn guianense (Aubl.) Sandw., Erblichia xylocmpa Standi. a nd Steyerm., Guatteria anomala R. E. Fries, Manilkara ac!tras (Mill.) Fosberg, Poulsenia armata (Miq.) Standley, Swietenia macrophylla King, Terminalia amazonia (G111el) Exell. The understory trees and the lower trees of the canopy that are most abundant are Alchornea latifolia Sw., Alibertia edulis (Rich.) Rich., Belotia cambellii Sprag., Bume!ia persimilis Hems!., Bursera simaruba (L.) Sarg., Cassia grandis L.f., Blepharidium mexicanum Standi., Gaurea exce!sa HBK., Hasse/tia dioica (Benth.) Sleumer, Licaria peckii (I.M. Jo hnst.) Kosterm., Orthion subsessile (Standi.) Standi. and Steyerm.,

!56

D. E. BREEDLOVE

Pithecelfobium arborewu ( L.) Urb., Quararibea funebris (La Llave) Visch., Sickingia sah·adorensis (Standi.) Standi., Wimmeria bartleffii Lundell, Zue/(llria guidonia (Sw.) Britt. and Millsp. (2) L ower montane rain forest. (Selva Alta Sicmpre Verde in part: Miranda, 1952, 1957; Selva Alta Pcrennifolia in part: Miranda and Hermindcz X., 1963; Gomez Pompa, 1965; Pennington and Sarukhan, J968'.) Inasmuch as most of Chiapas is momitainoLtS, this formation is much more co mmon than tropical rain forest. Most of the Eastern Highlands and large sections of the Northern Highlands along with a narrow band on the western base of the Sierra Madre are covered with this formation. The Sierra Madre forests have been cut or altered for the production of coffee, while those of the Eastern and Northern Highlands remain mostly virgin. This formation is physiognomically quite similar to tropical rain forest but lacks the uppermost story extending above the canopy. The canopy layer is 25-45 m high. Lianas and epiphytes are much more coinmon and epiphytes are spread throughout all of the forest layers. The forest floor is covered with a dense thicket ofspinescentpalms, cycads, low-branched shrubs and lianas making travel qn anything but established trails impossible. Most of the canopy and understory trees present in the tropical rain forest are present here. There are many additional species, incl uding the following canopy trees: Be!otia mexicana (DC.) Sch um., Calophyllum brasi/iense Camb., Chaetoptelea (Ulmus) mexicana Licbm., Licmria platypus (Hems!.) Fritsch, Nectandra sinuata Mez., Ocotea rubrif/ora Mez., Quercus o!eoides Cham. and Schlect., Quercus skinneri Benth., Sebastiana longicuspis Standi., Ta/auma mexicana (DC.) Don, and Vochysia hondurensis Sprague. Some of the more common understory and canopy trees include in addition to those cited for tropical rain forest : Chrysophy!lum mexicanum Brandeg., Cleidion oblqngifolium (Standi.) Croizat, Cymbopeta/um pendulif/orum (Dun.) Baiu., Faramea occidenta/is (L.) A. Rich., Pseudo/media spuria (Sw.) Griesb., Sloanea terniflora (M oe. and Sesse) Standi., Stemmadenia donnel!-smithii (Rose) Woods, and Troplris racemosa (L.) Urb. (3) Montane rain forest. (Selva Mediana y Baja Siempre Verde, in part: Miranda, 1952, 1957; Selva Mediana o Baja Perennifolia, in part: Miranda and HermindezX., 1963; G6mez Pompa, 1965; Pennington and Sarukhan, 1968.) Along the upper slopes and crests of all the ridges in the Eastern and Northern Highlands, along the eastern escarpment of the Central Highlands and along both slopes of the southern part of the Sierra Madre, occurs this formation composed of three or sometimes two layers of trees and a dense shrubby understory. Epiphytes including a profusion of mosses are characteristic of all levels of this formation. Epiphytic ferns, orchids, bromeliads, aroids, and many other groups are best developed here of all forest formations. Herbaceous plants are quite common on the forest floor. Montane rain forest can occur between 900 and 2200 m and is often associated with steep slopes. T he canopy

I'HYT EGEOGRA I'H Y AND VEGETATIO N OF CHIAPAS (MEXICO)

!57

is not nearly as continuous as that of lower montane rain forest and is often only ?_5- 35 m high although occasional taller trees arc common ly encountered. T he second layer is composed of shrubs and small trees between 5 and 15 m tall. The more common trees of the canopy layer are : Ardisia alba Lundell, Bnmel/ia mexicana Standi Hedyosmum mexicalll/111 Cordemoy, !vfatudea trinerria Lundell, Meliosma matuda; Lundell, Mosquitoxylon ja111aicense Krug. and Urban, Nectandra reticula/a (R. and Pav.) Mez, Oecopetalum mexicammr Grecnm. and Th oms., Oreopanax sanderianus Hems!., Oreopanax xa!apensis (HBK.) Dcnc. and Pl., Quercus peduncu!aris Nee, Platanus c!riapensis Standi., Rinorea guatemalensis (Wats.) Ba rth., Synardisia 1•errosa (Mast.) Lundell, Turpinia occidentalis Don. T he more common trees and shrubs of the understory are: Aca/yplra skwchii l. M. Johnst., Billia lrippocastammr Peyr., Cenlropogon cord(rtus Benth., Cephaelis axil!aris Sw., Cephaelis e/ata Sw., Clramaedorea concolor Mart., Eugenia rm·e11ii Lundell , Ham pea longipes Miranda, M iconia !auriformis Naud., Mo/linedia guatemalensis Perk., Oreopanax !iebmanii Marchal, Palicourea spp., Parathesis microca!yx Donn. Sm., Psychotria spp., Troplris mexicana (Liebm.) Bur. , Urera a!ceifolia Ga ud. (4) E••ergreen cloud forest. (Cloud Forest: Leopold, 1950; Selva Mediana y Baja Siempre Verde, in part: Miranda 1952, 1957; Selva Mediana o Baja Percnnifol ia, in part: Miranda and Hernandez X., 1963; Gomez Pompa, 1965; Pennington and Saru khan, 1968.) This formation consists of one to two layers of closely spaced trees and a dense shrubby understory. The canopy can be as tall as 40 m with straight smooth trunks in protected locations but it is often much lower especially on windswept ridges where it resembles the Elfm Woodland described by Beard (1944). Tree ferns are most common here although fl1ey a lso occur in montane and lower montane rain forests. There are a great many narrowly endemic species in t his fo rmation. Well-developed examples of this forest are scarce and rapidly disappearing from pressure of man. At present it occurs only about the crests of the highest peaks or the Central Highlands between 2,000 and 2,900 m and also in the Sierra Madre between 1,900 and 3,200 m. Lianas are al~ost completely absent in this formation; herbaceous vines, however, are quite abundant. Epiphytic angiosperms such as orchids and bromeliads are uncommon a nd limited to a few species. Mosses hang in sheafs from the branches and epiphytic ferns are common. Fog and clouds seem always to be hanging over these forests and account for much of the precipitation that falls here. Frost is common in January on cleared or exposed land adjacent to these forests, although the temperature rarely, if ever, drops to 0° centigrade on the forest floor. Common trees of the canopy are: Abies guatemalensis Rehder, Acer negundo L., Chiranthodendron pentadactylon Larreatequi, Clethra lana/a Mart. et Gal., Clet!rra oleoides Wms., Drimys granadensis L., Magnolia slrarpii Miranda, 0/medie/la betschleriana (Goepp.) Loes., Oreopanax capita/us (Jacq.) Dcne. and Planch., Persea donnell-smitlrii Mez ex Donn. Sm., Persea schiedeana Nees, Photinia matudai Lundell, Pinus ayacahuite Eh renb., Quercus acatenmrgensis Trel., fVeinmannia pinna/a L.,

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D. E. llREEDLOVE

PHYTOGEOG RAPH Y AND VEGETATION OF C HIAPAS (MEXICO)

Wimmeria driapensis Lundell. Common shrubs of the understo ry incl ude: Carendishia guatemaleusis var. cl!iapensis (Brand.) L. Wms., C!eyera tlteaoides (Sw.) Choisy, Deppea grcmdijfora Sc hlecht., Eugenia tonii Lunctcll, Fuchsia micropliy/la su bsp. aprica (Lundell) J3recd l., Fuchsia paniculata Lind!., Gent/ea micrantha (Donn.Sm.) Lundell, Jvfahonia paniculata Forst., Miconia rarenii Wurdack, Rapanea juergensenii Mez, Saurauia oreopl!i/a Hems!., Symplocos limoncil/a H. ct B., Vaccinium conferlum 1-1BK., Viburnum blandwn Morton.

incl ude: Amyris cliiapensis Lundell, Ardisia escallonioidC's S. and C., Bourrerialruanita (-la Llavc ct Lex.) Hems!., Clusiaf!am Jacq ., Eugenia acapulcemisStead., Ca/yptrantiles chiapensis Lundell , Gentlea renosissi111a (R. and P.) Lundell, Kanvinskia ca/deronii Stand i., P~>ychotria erytilrocarpa Schlec ht.

Seasonalfornrations Well over hal f of the forest area of C hiapas consists of Seasonal formations. These format ions are q uite diverse physiognomically but are fl oristically related and form bands of intergradation. Characteristically, they are open fore sts wit hout a closed canopy. Some percentage of deciduous trees occur in all of the formations. The forest floor does not have a continuous understory ; however, shrubs are common. Lianas are uncommon or totally absent in most of these fo rmations, whereas epiphytic a ngiosperms are abundant and can become more prominent than jn the optimum formations. !3piphytie mosses are poorly developed. ' ( 5) E1â&#x20AC;˘ergreen and semi-el'ergreen seasonal forest. (Selva Alta S u bdec"id ua: Miranda,

1952, 1957; Selva Alta o Mediana Subperennifolia: Miranda and Hernandez X., 1963; Gomez Pompa, 1965; P ennington and Sarukhan, 1968; Selva Alta o Mediana Su)Jcauducifolia: Miranda and Hernandez X., 1963; Gomez Pompa, 1965; Pennington and Sarukhan, 1968.) Although often split into two formations, the zones of intergradation are so large as to make the distinction meaningless. This is the first in a transitional series of forest types from tropical and lower montane rain fo rests to thorn woodland. Superficially, it is quite similar to the rain forest fo rmations but differs in havi ng only two and sometimes one layer of trees. The canopy is discontinuous and contains some percentage of deciduous trees, depending on the aridity of the locality. The fores t attains a height of 25- 35 m. The dry season is very marked and the forest floor becomes quite dry. There is a great seasonal variation in herbaceous plants. Lianas and epiphytes are usually quite abundant. This formation is common on the western and northeastern slopes of the Sierra Madre (up to 1,200 m), in the southern an d western portions of the Northern Highlands and on the Gulf Coastal Plain. Some of the common trees of this formation are: Astronium graveolens Jacq., Bernoullia flammea Oliver, Brosimum alicastrum Sw., Bumelia persimilis Hems!., Ceiba pentandra (L.) Gaertn., Calycophyllum candidissimum (Vahl) DC. , Cordia alliodora (R. et P.) Cham., Enterolobium cyclocarpum (Jacq.) Griesb., Ficus glaucescens (Liebm.) Miq., Guettarda combsii Urban, Hymenea courbaril L., Lafoensia punicaefolia DC., Licania arborea Seem., Platymiscium dimorphandrum Donn. Sm., Sapium macrocarpum Muell. Arg., Sterculia mexicana R.Br. , Tabebuia chrysantha (Jacq.) N ichols, Vatairea lundellii (Sta ndl.) Killip. Common shrubs and small trees

159

(6) .Tropica~ deciduous forest. (Deciduous Seasonal Forest: Beard, 1944; Selva Baja DCCJdua : M1randa, 1952, l 957; Selva Baja Cauducifolia: Mi randa and Hermindez x 1963; Penni nglon and Sarukhan, 1968; Bosque Tropica l Dcciduo: Rzedowski an~ McVaugh, 1966.) This is a diverse association of decid uo us and semi-deciduous trees which is common in dry situations from Sonora to Panama. This associat io n is normally between 10 and 20m high with a dense, thicket-like understory. H owever, in some protected semi-riparian situations the trees can be as tall as 40- 50 m with straight trunks and a low understory. T here arc many species of trees common in th is association and the dominants vary with the environment of the specific locality. Lianas and epiphytes are present but qu ite reduced in number. The dry season is very long (4-6 months) and severe. Almost all of the trees and understory pla nts lose their leaves. Many trees flower at th is time and a re qui te showy, but the general appearance is of complete dormancy. A few weeks after the rai ns begin this once-desert looks like a verdant jungle. Many hundreds of species of herbaceous plants sprout and cover the gro und, often producing a stand of 1-2 m high. In Chiapas one find s tropical deciduous forest prevalent along the Coastal Plain and the lower hills of the Sierra Madre. It is also common throughout much of t he Central Depression. Some of the common trees are: Bursera excelsa (HBK.) Engl., Bursera simaruba (L.) Sarg., Calycoplryl/um candidissimum (Vahl.) DC. , Cecropia pf!..llata L., Cedrela oaxacensis C. DC. and Rose, Coclrlospermum l'itifolium Willd. ex Spreng., Cordia a!liodora (R. and P.) C ham., Eysenlrardtia adenostylis Baill., Gliricidia sepium (Jacq.) Steucl ., Godmania aesculifolia (HBK.) Standi. , Hauya e/egans HBK., flura polyandra Bail!., L11elrea candida (DC.) Mart., Lysiloma aurita (Schl.} Benth., Pseudobombax e/liiJticum (HBK.) Dugand, Spondias mombin L., Tabebuia chrysantha (iacq.) Nichols., Tabebuia rosea (Bertol.) DC., Triplaris melaenodendron (Bert.) Standi. and Steyerm.

(7) Short-tree smâ&#x20AC;˘anna. (Sabana: Mirand a, I 952, I 957; Miranda and Hernandez X., 1963; Gomez P ompa, 1965; Pennington and Sarukhan, I968; Selva Baja Subperennifolia : Miranda and Hernandez X., I963; Vegetacion Sabanoide: Rzed owski and McVaugh, 1966; Savanna: Beard, 1953; Leopold, 1950; Lundell, 1934, 1937.) Confusion as to the application of the term "savanna" and the questioning of the nature of this type of vegetation concerning whether it represents a climax or a dis-climax in response to the activities of man, along with the great variety of associations and situations which fa ll under this term, has led to the adoption by tbe author of the above term to refer to a very abundant vegeta tional association of grasslan d and spaced low trees usually occurring on deep, poorly drained, soils. It is commonly found on gradual sloping plruns or on flat bottom lands. The trees are low and gnarled,

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D. E. l3REEDLOVE

and usually well spaced; Lhcy rarely attain a height of more than 20 m. In some situations (described by Miranda and .Hermindez X., 1963 as Selva Baja Subpercnnifolia) the trees will form a low fo rest with a grass unclerslory. Four species of Lrees, Byrsonima crassifolia (L.) DC., Crescell/ia cujete L. , Crescentia a/ala HBK. a nd Curate/la americana L., are Lhe most characterist ic of this formation. Piscidia piscipula (L.) Sarg., Ah·aradoa amorplwides Licbm., Acacia pennatula (S. and C.) Benth., and occasio nal species of palms also can be fou nd here, either singly, or in association with the other mentioned species.

(8) Thorn woodland. (Selva Baja Espinosa Cauducifolia: Miranda and Hern{mdez X., 1963; Pennington a nd Sa rukluin, !968; Bosque Espinoso: Rzedowski and MeVaugh, 1966.) This is a dense association of shrubs and low trees which is often quite uniform in appearance. The majority of the species present are armed wi th an assortment of spines, thorns and prickles. This fo rmation usually occurs on poor, rocky soils on slopes adjacent to stands of short-tree savanna of tropical deciduous fo rest. Thorn woodland is poorly developed in Chia pas, limited to the northern parts of the Central Depression and the Pacific Coastal Plain. It is, however, quite prominent in the Isthmus of Tehuantepec , just no rth of the state line. The more common associates are: Acacia farnesiana (L.) Willd. , Acacia pringlei Rose, Acacia cornigera (L.) Willd., Bauldnia a/biflora Britt. and Rose, Bauhinia pau/etia Pers., Casearia nitida Jacq., Cordia curassal'ica (Jacq.) R oem. and Schult., Croton guatema/ensis Lotsy, Diphysa fioribunda Peyr., Ja cquinia aurantiaca Ait., Piptadenia jfat•a Benth., Pithecel/obium dulce (Roxb.) Benth., and Randia aculeata L.

(9) Pine-oak-Liquidambar forest. ( Deciduous Forest: Miranda and Sharp, 1950; Bosque D eciduo : Miranda, 1952 ; Pine-Oak-Liquidambar Forest: Carlson, 1954; Bosque : Miranda, 1957; Bosque Cauducifolio: Miranda and Hernandez X., 1963, Pennington and Saruklu1n, 1968.) On the moist north and east escarpments of the Central Highlands and a t scattered localities in the Northern Highlands and on the eastern escarpment o f the Sierra Madre, occurs a diverse association with many species of deciduo us and semi-decid uous trees. Epiphytes are very common, with numerous species, and oaks are often so heavily laden that one can barely see the branches. The understory is variable, ranging from a dense association with many species of shrubs, subshrubs and vines, to a tall grassy expanse with scattered shrubs. The t rees are commonly between 15 a nd 35 m tall and can be widely spread; but usually are close enough for their crowns to form a continuous can opy. Many of the trees are quite broad-crowned. This association is always diverse and one never finds pure stands of one or two species. Some of the common species of trees are: BruneIlia mexicana Standi., Carpinus caroliniana Walt., Citharexy/um donnell-smithii Greenm., Clethra suaveolens Turcz., Cornus disciflora DC., Cupania dentata DC., Cassia oxyphylla HBK., Erythrina chiapensis Krukoff, Fraxinus uhdei (Wenzig.) Lingel, Liquidambar styraciflua L., M ontanoa hexagona Rob. and Greenm., Nyssa sylvatica

I'H YTOG EOGRAJ'HY AND VEGETATIO N OF CH I A PAS (MEXICO)

16 t

Marsh, Ostrya guatemalemis (W ink!.) Rose, Pinus clriapensis (Martinez) Andersen, Pinus montezumae Lamb ., Quercus candicans Nee, Quercus oocarpa Schicde, Quercus po/ymorpha S. a nd C., _Quercus sapotaefo/ia Liebm., Quercus segoriensis, Quercus skinneri Benth., Rhus striata Ruiz and Pavon, Saurauia scabrida Hems!., Styrax argemeu.1· Pres!, Turpinia occidentalis (Sw .) D. Don. The following sh rubs are common in the understory: Aplre/andra gigantiflora Lindau, Bacclraris trinenis (Lam.) P ers., Bocconia gracilis I-1 utch., Cestrum gualemalensis var. gracile Morton, Firclrsia micropll);lla s ubsp. quercetonrm Drecd l. , Gaultheria odorata Willcl ., Guamatela tuercklreimii Do nn.Sm. , Hibiscus bijirrcatus var. pi/osus Gurke, Liabum g/abrum var. hypo/eucum Cogn., Parathesis clriapensis Fern., Plrenax rnexicwws Wedel., Rapanea myi'icoides (Schlech t.) Lundell, Rlrus terebinthijo/ia S. and C., Solanum brachystaclrys Mart. and G al. , Symplocos /ongipes Lundell, Triwn{ella grandiflora Yah!, Verbesina perymenioides Sch. Bip., ViburnumJrartwegii Bent h.

( 10) Pine-oak forest . (Pine-Oak F orest : Leopold, 1950; Pinares and Encinares : Mirand a, 1952; Miranda a nd Hernandez X., 1963; .Bosq ue de Pino y Encino : Rzedowski and McVaugh, 1966.) On the dryer south and west slopes of the Central Highlands, and on the eastern escarpment of the Sierra Mad re, an open forest associat ion occurs, comprised of relat ively few species of trees. Mixed pines and oaks are most common; however, stands of p ure pine and pure oak occur in specialized edaphic situat ions. Trees range in height from 15 to 40 m a nd can be quite variable in their spacing. Epip hytes are sparse to common, but only heavy in canyon situations. The understory is usually herbaceous with occasional shrubs and often only low grassy patches between the trees. T his formation is predominan t between I ,300 and 2,500 m, with occasional associations occurring as low as I ,000 m. T he common trees are: Arbutus xalapensis HBK., Buddleia skutchii Morton, Crataegus pubescens (HBK.) Steud., Pinus michoacana M artinez, Pil1us oaxacana Mirov., Pinus oocarpa Schiede, Pinus pseudostrobus Lind!., Quercus acatenangensis Trel., Quercus corrugata H ook., Quercus crassifolia H. and B., Quercus mexicana H . and B., and Quercus rugosa Nee. T he followin g sh rubs are common in this format ion : Buddleia crotonoides A. Gray, Ceanotlrus coeruleus Lag., Clriococca p/raenostemon Schlecht., Garrya laurifo/ia Hartw., Holodiscus argenteus (L.f.) Maxim., Lippia chiapensis M o ldenke, Litsea neesiana (Schauer) Hems!., Mailonia l'ulcania Standi. and Steyerm., Monniria xa/apense HBK., Myrica cerifera L., Rhus schiedeana Schlecht., Senecio cristobalensis Greenm., Solamoil nudum HBK. , Solanum lrispidum Pers., Viburnum jucundum M orton. Wet-landforest formations (11) Swamp and lowland riparian forest. (Manglar, in part: Miranda and Hermindez X., 1963; Canacoital: Pennington and Sarukhan, 1968.) Along all of the lowland rivers, especially where the water is slow moving, in flat, periodically inundated ateas where water stands for some months of the year, and in fre sh-water swamps directly

162

D. E . B RE EDLOVE

behi nd the mangrove swamp, this ve ry distinctive fo rest type occurs. The trees ca n often attai11 a heigh t of 40 m wit h a contin uous canopy, and blend into the surrou nding fo rest, but can also be as low as 15- 20 m and occur in discontin uous patches of promi nen t green in a sea of dryer vegetat io n. T he trees arc characteristically buttressed and often have st ilt roots and aerial roots resembling mangrove swamp. Stands of single or few species arc common in this formation. The understory is sparse and usually herbaceous. Some of the common trees found here are: Andira galeolfiana Standi., Bravaisia integerrima (Spreng.) Stand i. , Bucida brrceras L., Calophyllrrm brasiliense var. rekoi Standi., Haematoxylum campechiamm1 L. , Pachira aquatica Aubl., Salix chilensis Mol., Taxodium mucronatum Ten.

(12) Mangrore swamp. (Mangrove Swamp: Standley and Steyermark, 1945; Steyermark, 1950; Manglar: Miranda, 1952, 1957; Miranda and Hermindez X., 1963; Rzedowski and MeVaugh, 1966; Pennington and Saruk h1in, 1968.) Forming almost a continuous belt of low forest cover, th is formation inhabits the entire Pacific coast of Chiapas in brackish, swa mpy conditions. This swamp is several kilometers wide in the north, in the region of the Mar Muerto, but only a few hundred meters wide along the rest of the coast. The vegetation is uni form and dense with the-shrubs and trees with stilt roots and simple, thickly cutinized leaves. T he stands are usually 4-7 m high but occas i o ~ a ll y attain a height of 10-20 m. This association is widespread along the coast of tropica l America as far north as Sonora and Baja California. The dominants are: A ricennia nitida, Jacq., Conocarpus erecta L., Laguncu/aria racemosa (L.) Gaertn ., Rhizophora samoensis (Hochr.) Salv. (13) Pa!m.forest. (Palmar: Miranda, 1952, 1957; Miranda and Hermlndez X., 1 963~ Rzedowski and McVaugh, 1966.) Along sandy alluvial flats and terraces of the upper portion of the Central Depression and along the Rio Usumacinta and its tributaries in the Eastern Highlands and in scattered localities in the southern portion of the Pacific Coastal Plain, often in poorly drained soils, a forest occurs in which palms are the predominant tree with a sparse understory. (A much more dense u nderstory is Âˇcommon in these forests in the Eastern Highlands.) The palms reach between 24 and 40 m in height, and can occur qui te closely spaced. Some of the common savanna trees a re often associated with the palms. The dominant trees are: Saba/ mexicana Mart., Schee/ea liebmannii Becc., Schee/ea preussii Burrel. (14) Temperate riparian forest. Along streams above 1500 min the Central Highlands and the Sierra Madre, a number of trees and shrubs are common which do not occur in abundance in the surrounding forest. The understory is dense and often thicketlike. Trees are mostly between lO and 25 m tall and can occur in very pure stands. The most common species are : Acer negundo var. mexicanum (DC.) Standi. and Steyerm., Alnus arguta (Schlecht.) Spach, Alnus ferruginea HBK., Baccharis heterophyl/a HBK., Berchemia scandens (Hill) Trel., Cornus excelsa HBK., Crataegus pubescens (HBK.) Steudl., Cuphea hyssopifolia HBK., Platanus chiapensis Standi., Salix bonplandiana HBK ., S alix taxifolia HBK.

PHYT OGEOGRA PH Y AND VEGETATI ON OF C HIAPAS (MEXICO}

163

Treelessfonnations (15) Bunch grassland (Zacatonal : Miranda, 1952, 1957; Mi randa and HermlndezX., 1963.) At high elevations in the Central Highlands and in the southern Sierra Madre, there occur large stands often up to severa l hectares, of tall bunch grasses. The clumps are closely spaced and can be as tall as 2 m. The origins of this association may be secondary, but it appears to be quite stable. Common species are: Briza rotundata (HBK.) Hitchc., Bromus carinatus H. and A., Festuca ainpli.ssima Rupr., M1ddenbergia gigantea (Fourn.) Hitchc., Muh/enbergia macroura HBK., Muhlenbergia robusta (Fourn.) Hitchc., Stipa iclw (R. and P.) Kunth. , Stipa rirescens .HBK., Trisetum irazueme (Kuntze) Hitchc.

( 16) Paramo. (Paramos de Altura: Mira nda 1952, 1957; Miranda and Herm\nclez X., 1963) This is a low association of grasses and herbaceou s perennials foun d only around the summit of the Volcan de Tacana. Similar second growth associations occur in overgrazed areas at very high elevations in the Central Highlands. The associates arc: Alchemilla pinna/a R. and P., Arenaria bryoides Willd., Calamagrostis to/ucensis (H BK.) Trin., Draba ro/canica Benth ., Festuca tolucensis HBK., Gentiana pumilio Standi. and Steyerm., Gnap/wlium l'ulcanicwu I. M. Johns!., Haplopappus stolo11ijerus DC., Lobelia nana HBK., Luzula racemosa Desv., Pernellya tomasii Camp., Polenrilla heterosepala Fritsch, Viola na1mei Polak, Weldenia candida Schult., Werneria nubigena HBK. ( 17) Herbaceous marsh. (Tulare : Miranda and Hernandez X., 1963; Popal : Mi randa and Herm\ndez X., 1963.) This distinct herbaceous cover of shallow standing water has very different associations in temperate and lowland situations. ln the larger non-draining valleys of the Central Highlands and in local areas of the Sierra Madre a temperate marsh occurs which is often associated with bogs. Carex spp., Cfadium jamaicense Crantz, Cyperus spp., Juncus spp., Ludwigia peruriana (L.) Hara, Ly tlmon rulneraria Schrank, Rhynchospora spp., Scirpus californica (C.A. Meyer) Steudl., and Typha latifolia L. are common associates. Large tracts of the Gulf Coastal Plain and some smaller areas on the Pacific Coastal Plain are covered with a tropical marsh which in some areas becomes quite dry seasonally. In addi tion to many of the species p resent in the temperate marshes these lowland association s have the following common species: Calathea spp., Heliconia bihai L., Hymenachne amplexicaulis (Rudge) Nees, Leersia spp., Paspalum spp., Phragmites communis Trin., and Thalia genicula/a L.

(18) Coastal strand. (Cordon Littoral: Miranda, 1942.) On sandy portions of the Pacific Coast, there occurs a low, herbaceous association of dune plants. The dominants are : Distich/is spicata (L.) Greene, and Ipomoea pes-caprae L.

(19) Second-growth and successional forest, and shrub associations. Either for lumber,

164

D. E. BREEDLOVE

pasture, o r some crop, great ex panses of virgin forest arc presentl y being cut down in Chiapas. rn many areas strcccssional forests a r·c being cut for the plan ting of maize or for firewood and charcoal. These decimated lands recover slowly and it would take several centuries to replace the primary forest. Second-growth associations arc prominent and arc, in some areas, the dominant vegetation. T his account does not attempt to describe the myriad of possi ble successions and their component associations. One example to illustrate vegetation type is given here. When the pine-oak, pine-oak-Liquidambar and evergreen cloud forest associations are cut oiT, burned, planted to maize and, after a few yea rs, allowed to grow back, the rege neration begins with a scru b association which can last up to 10 years. This manperpetuated succession has bee n going on in this area for several thousand years. Many of the races of maize used arc narrowly restricted endem ics. This association is naturally quite variable in its composition depending upon the locality and the forest type which it is succeeding. £tis usually a quite un ifo rm cover of shrubs and herbaceous plants up to 3 m tall. Common species are: A butilon tridens Standi. and Steyerm., A cacia augustissima (Mill.) Kuntze, Arctostaphylos Iucida (Small) Standi., Bacc/wris I'Occinioicles H 13K., Cal/ia/l(fra grandiflora (L'Hcr.) Benth., C~l/iandra lwustoniana (Mill.) Kuntze, Ceanotlws coemleus Lag., Clibadiwn arboreum Donn. Sm., Coaxana ebracteata Rose, Lantana hirta Grah., LCIIztana lriJ1Jida HBK., Lippia hypo/eia Brig., Malrar·i scus arboreus Cav., Muelzlenbeckia tamnifolia (HBK.) Miessn., Paronia paniculata C-av., Polymnia maculata Cav., Rhamnus discolor (Donn.Sm.) Rose, Rhamrws nelsonii Rose, Rubus spp., Sahia spp., Tithonia diversifo/ia (H ems!.) A. Gray, Tithonia scaberrima Bent h., Vemonia leiocarpa DC., Vibumum /autum Morton.

References Beard, J. S., 1944. Climax vegeta tio n in tropical America. Ecology, 25(2) : 127- 158. Beard, J. S.,l953. The savanna vegetation of n or thern tropical America. £col. M ouogr., 23(2) : 149215. Carlson, M. C., 1954. F loral elements of the pine·oak-Liquidambar forests o f Mo ntebello, Chiapas, Mexico, Bull. Torrey Bot. Club, 81 (5) :387-399. Contreras A rias, A., 1955. Definicion de las zonas aridas y su delimitacion en el territorio Mexicano. Jn: Mesas Redondas sabre Problemas de las Zonas Aridas de Mex ico. lnst. Mex. Rec. Nat. Rcnovables, A.C., Mexico, D. F., pp.3- 24. Goldman, E . A. and Moore, R. T., 1945. T he biotic provinces of Mexico. J. Mammatogy, 26:347-360. Gomez-P o mpa, A., 1965. La vegetaci6n de Mex ico. f3ol. Soc. Bot. Mex., 29:76-120. H elbig, K. M ., 1964a. £/ Socouusco y su Zona Cafetalera eu Chiapas. Institute de Ciencias y Aries de C hiapas, T uxtla Gutierrez, C hiapas, 134 pp. H elbig, K. M., 1964b. La Cuenca Superior del Rio Grijalva. Inslitulo de Ciencias y A rteS' de C hiapas, Tuxtla Gutierrez, C hiapas, 247 pp . L eopo ld, A. S., 1950. Vegetation zones of Mexico. Ecology, 3 1 :507-518. Lundell, C.L .. 1934. A p reliminary sketch of the phytogeography of the Yucatan peninsula. Cantrib. Am. Archeot., 12:255- 321. Lundell, C. L., 1937. The vegetation of Peten. Carn.lnst. Wash., Pub/., 478:1-244. Lundell, C. L., 1942. Flora of eastern Tabasco and adjacent Mexican areas. Contrib. Univ. Mich. Herb., 8: 1-74.

PHYTOGEOGRA PH Y AND VEGETATION O F C HIAI'AS (MEXICO)

165

Miranda, F ., 1942. Estudios sobrc Itt vcgetaci6n de Mex ico, 2. Obscrvm:ioncs prclimina rcs sobre Itt vcgctaci6n de Itt region d e T a pachula, C hiapas. Anales Jmt. lliol. , 13( 1):53-70 . Minmda, F., 1952. La Ve~:etacitin de Cltillpas, 1. Edkioncs del Gobicrno del Estado, Tux rla Gutierrez, Chiapas, J34 pp. . Miranda, F., 1957. Vcgetacion de Ia vcrticnte del pacifko de Ia Sicrrtt Mttd rc de Chiapas (Mexico) y sus rclacioncs Ooristicas. Pmc. Poe. Sci. Congr., 8tlr, 4:438-453. Miranda, F., 1961. Trcs estud ios b otanicos en Ia Sl!iva Iacandona, Chiapas, Mexico. Bol. Soc. But. Mex.,26: 133- 176. Miranda , F. a nd 1-lern{lndcz X., E., 1963. Los T ipos de Vcgctaci6n de Mexico y su clasificacion . Bul. Soc. Bot. Mex., 28:29- 179. Miranda, F. and Sharp, A . J .. 1950. Characteristics of the vegetation in ccrt<tin temperate regions of eastern Mexico. Ecology, 3 1(3) :31 3-333. Mullericd, F . K. G ., 19'57. La Geologia de Chiapa.1·. Gobie rno Constitucional del Estado de C hiapas, Tuxtla Gutierrez, 180 pp. Pennington, T. D. and Sarukha n, i , 1968. Arboles Tropica/es de Mexico. lnstituto Nacional de Investigaciones Forestales, Mexico D.F. and O rganizacion de las Nacioncs Unidas para Ia Agricuhu ra y Ia A limen tacion, R ome, 413 pp. Rzcdowski, )., 1965. Rclaciones geograficas y posibles origenes de Ia flora de Mexico, Bot. Soc. Bot. Mex., 29 :121-171. Rzcdowski, J. and McVaugh, R ., 1966. La vegctaci6n de Nueva Galicia . Contrib. Univ. Mich. Herb., 9(1):1 - 123. Standley, P. A., 1940. The forests of Guatema la. Trap. Wood.,, 67:1-18. Standley, P. A. and Stcycrma rk, J. A., 1945. Vegetation of Guatemala . Jn: F. Verdoom (Edito•·), Plants and Plaut Science iu Latin America. Chronica Botanica, Waltham, Mass., pp.275- 278. Steyermark, J. A., 1950. Flor.Jl of Guatemala. Ecology, 31 :368-372. Vogt, E. Z., 1969. Ziuaca/1/tm: a Maya Co/1/lllllllity iuthe Highlands of Chiapa.r. Belknap Press, Cam- ~ bridge, Mass., 733 pp. Wagner, P. L. , 1964. Natural vegetat io n o f Mid dle America. In: R. Wauchopc (Editor), Handbook of J\lliddle American Indians, I. Natural £111•iromneutaud Early Culture. Univ. of Texas Press, Austin, Texas, pp.216- 264. Williams, L., 1938. Forest trees of the Isthm us of Tchuantcpcc, Mexico. Trap. Wood.r, 53: 1- 11. Williams. L., 1939. Arboles y arbustos dellstmo de Tchuantepec, Mexico. Lil/oa, 4: 137- 171.

Chapter 6

The Vegetation of Panama: a Review DU NCAN M . .PORTER Smithsonian lustitllliou, Washington D. C. (U.S.A.)

Summary The physiograph y, climate, soils, and t he influence of man on the vegetation of the Isthmus of P anama are outli ned. Followi ng a brief disc ussion of the vegetation maps of the isthmus that heretofore have been produced , more detailed critiques are offered of Bennett's (1968) and Myers' (1969) maps of Koppen M acroclimates, Holdridge and B ud owski's (1956, 1959) map of H oldridge Life Zones, Bennett's ( 1968) map indicating human d isturbance, and Duke's (Duke and Porter, 1970) map of Darien forest types. The last section of the paper p resents lists of species and their relative abundance, when-given, that investigators have reported from various plant commun ities in the Republic of Panama and the Canal Zone. ~

Introduction The Isthmus of Panama stretches sinuously between Costa Rica on the west and Colo mbia o n t he east; north is the Car ibbean Sea, so uth the Pacific Ocean (Fig. I)

Fig.!. Map of Panama, showing political subdivisions.

168

D. M. PORTER

THE VEG ETATION OF PANAMA : A REV IEW

169

The Continental Di vid e lies approximately along the center of the western part of the isthmus. In the low central par!, ius much closer to the Pacific side, while in the eastern half it lies closest to the Caribbea n shore. Flat and gently sloping low land plains arc not common on the isthmus. Most lowland areas are dissected by rivers and low ridges and hi lls. The most extensive lowlands occur on the Pacific side. These are in the provinces of Darien, Panama, Code, VcragLias, and Chi riq ui, and on the Azuero Peninsula. Lowland areas on the Caribbean side are mai nly west of the Canal Zone in Colon and Panama provinces and in the vicinity of Chiriqui lagoon in the province of Bocas del Toro. I '

o •• ~OO rn

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IH Fig. 2. Map of Panama, showing elevations. (After Myers, 1969.)

Geograph ically and biologically, this geologically rather recen! isth mus is a bridge between Cent ral and South America. I t has the shape of a sigmoid curve, lying between 7• 10' and 9°40'N, with its axis runn ing essentially east and west from 77° 15' to 83°30'W. In the center of the isthmus, bisecting the Republic of Panama, lie the Panama Canal and the Canal Zone. The Republic of Panama and the Canal Zone together cove r about 48,000 km 2 . It is 676 km from border to border, and the ist hmus varies from 50 to !93 km in width. Elevations range from sea level to 3,427 m, but most of the ist hmus has an elevation of less than 500 m, and nea rly 90% is less than I,000 m high (Fig.2). The western half of the isthmu s is traversed by two ~;;o n ti n uou s volcanic and igneous mountai n ranges with Panama's highest elevations. The Cordillera de Talamanca in the west is conti nuous with the eastern highlands of Costa Rica. The eastern Serrania de Tabusara and its assoc iated high lands are separated from the mountainous areas or eastern Panama by about 65 km of lowland s in the center of the isthmus. The Panama Canal was built across this break in the isthmus' backbone, which here is a little over 60 m above sea leveL South of t he Serrania de Tabasara, the Azuero Peninsula juts out into the Pacific Ocean. Much of the Azuero Peninsula is low, but near its southwestern end it rises to the isolated Cerro Hoya, with an elevation of about I ,500 m. Elevations in the eastern half of. the isthmus are much lower than those in the west, few areas rising over 1,000 m. The long Serrania de Darien, which parallels the northeastern coastline, in the main averages between 300 and 600 m high, with higher elevations in its southernmost parts. The highest spots in eastern Panama are isolated peaks, the highest of which is Cerro Tacarcuna, on the Colombian border, with an elevation of 1,859 m.

Rainfall patterns and temperatu re are the most impor tant climatic factors for plant distribution in the humid tropics. Elevation and temperature are closely interrelated; temperature decreases as elevation increases. Variatio ns in monthly mean temperatures appear to be slight at all elevations in the tropics. Diurnal temperature variation, however, becomes more important as elevat ion increases, the range becoming wider as one goes higher. The tropical year is not divided into seasons by variations in temperature, as is true for the temperate zones. fn the tropics the year is divided into wet and dry seasons on the basis of the relative amounts or rainfall falling at different times. L stress relatil•e amounts of rainfall, because a month with 12.5 em of rain at Balboa Heights, on the Pacific side of the Canal Zone, will be part of the wet regime, while ~t Changuinola, Bocas del Toro, it will fall into the dry season (Panama Canal Company, 1967). The climate of Panama is greatly influenced by the Intert ropical Convergence Zone (lTC), that area where the trade winds from the Northern and Southern Hemispheres meet. The lTC roughly parallels the equ ator. Heavy precipi tation .and unstable rising air masses are associated with the lTC throughout much of the humid tropics. The ITC shi fts north and south with the seasonal shifting of the sun. In the eastern Pacific, it dips southward to reach th e equator in January, rarely reaching 2° or 3°S. In July the lTC has moved northward to lie along the fsthmus of Panama, but it apparently does not enter into the Caribbean Bas in (Trewartha, 1961 ). This latitudinal shifting of the lTC has a profound effect on the weather of Panama. In the Pacific lowlands, the wet season is essentially from May through December, and the dry season, usually with less than 5 em of rain per month, from January through Apt iL In some localities periods as long as two months without measurable precipitation have been reported. The dry season on the Pacific side is less pronounced at higher elevations, with some areas reported to be almost continually covered by low-lying cloud ~. The dry season in most of lowland Caribbean Panama is not so pronounced as

170

D. M.l'ORT ER

that of the Pacific side. When the lTC is at the equator in January, and the dry season has begun in Paci lk Panama , the Caribbean side of the isthmus is influenced by moisture-laden clouds that have formed over the Caribbea n Sea and arc now moving · southwa rd. Most of their precipitation falls on the Caribbean side. This results in a few lowland locali ties having no apparent dry season at all. Altitudinal effects on precipitation are even more pronounced on the Caribbean slopes than on the Pacific. As a generalization, it may be said that the vegetation on the Caribbean side is more mesophyt ic and less seasonal than that on the Pacific side.

Soils Tempera tu re and precipitat·ion clearly are not the only parameters affecting plant distribution in Panama. Edaphic factors may be just as important. However, few vegetation stud ies mention edaphic factors, and fewer studies still have been made on Panamanian soils. In· the soils maps that I have examined (Bennett , 1912, 1929; Martini et al., 1960), there appears to be little or no correlation. between soil types and vegetat ion types. However, those plant communities dominated by a single species, such as Prioria copaifera in the Freshwater Swamp Forest of Darien, have specialized edaphic conditions. As those familiar with tropical vegetatio n are well aware, there are few communities in the humid tropics with a single do minant species. Usually there arc a large number of common species, with some of the lusher Panamanian forest communities having upwards of 50 species of large and conspicuous trees scattered throughout.

- Man Probably the most importa nt influence on Panama's vegetation since pre-Colu mbian times is man. Man's fires, axes, and domestic animals have had a profoun d effect on the plants of the isthmus. This effect is by no means limited to the drier lowland commun ities. I have seen hundreds of hectares of blackened hillsides where once rose forests with over 2,500 mm of average annual precipitation (Porter, 1970). Such areas were cut.and burned to provide grazing grounds for cattle. It is only after these forests are cut and burned that the cattlema n finds that the resulting growth will not support a significant amount of grazing. Even the mangrove communities are not immu ne to the hand of man. Mangrov es long have been exploited for charcoal, but now they have fallen victim to another offspring of technology, the oil-spill (Riitzler and Sterrer, 1970).

TH E VEGETA TION O F PANAMA : A REVIEW

171

Vegetation

Vegewtion maps There have been a number of attempts to produce a map indicating the vegetatio n of Panama. These have been either as a part of a larger map of Latin America (Smith and Johnston, 1945), Central America (Trejos and Archer, 1953; Holdridg e, 1957; Lauer, 1960; Shelfo rd, 1963; Wagner, 1964; Stuart, 1966), southern Central America (Sapper, 1900; James, 1950), or a map of Panama itself (Goldman, 1920; Goldman and Zelek, 1926; Platt, 1938; Schery, 1942; Garver, 1947; Holdridge and Budowski, 1956, 1959; Bennett, 1968; Myers, 1969). The vegetation of parts of the isthmus also has been mapped, incl uding eastern Pana.ma (Lamb, 1953; Gollcy et al., 1969; Duke and Porter, 1970; Viksne et al., 1970), San Jose Island (Erlanson, 1946; Johnston, 1949), Barro Colorado fsland (Park eta!., 1940; Bennett, 1963), and Fort Sherman and Fort Gulick (Wiley et al., 1955). The vegetation of Darien Province has been mapped in detail (Duke and Porter, 1970), but few detailed vegetat ion maps are available for most of the isthmus. Almost all maps that have been produced show only the gross plant formations, and even these maps may vary marked ly from one another. T he only maps of which I am aware that attempt to deli mit plant communities on a large scale are those of Johnston (1949) for San Jose Island and Duke (Duke and Porter, 1970) for Darien.

Koppen macroclimates Bennett (1968) and Myers (1969) recently have produced maps of Panama delimitin g the Koppen macroclimates. Fig.3 combines their results. Many investiga tors feel that

f•opi«olW•tiAI J

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172

D. M. PORT ER

Koppen macroclimatcs, which arc based on tem perat ure and precipitat ion, arc broadly equiva lent to major vegetation types. Koppen's A and C cli mates occu r in Panama. A cl imates arc tropical rainy climates with no cool season, the average tempera ture of the cooles t month being above 18°C. c cli mates arc warm temperate climates with mild win ters, the average temperat ure of the coldest month being between 18 and - 3°C, and that for the warmest month over 10°C. . Climates reported for Panama are Tropical Wet, with no dry season and all months hav ing over 6 em precipitation, equated with L owland Tropical Rain Forest; Tropical Monsoon, with a short dry season, but rainfall during the wet season sufficient to compensate for it, and all months having over 6 em precipitation, equated with Monsoon Forest; Tropical Wet and Dry, wi th a longer dry season having at least one month with less than 6 em precipitation and insufficient rain during the wet season to compensate for it, equated with Tropical Deciduous Forest; Temperate Wet, with high rainfall and no distinct dry season, the lowest month receiving more than 3 em precipitation, eq uated with Montane and Lower Montane Rai11 Forests; and Temperate Wet and Dry , with high rainfa ll and a distinct dry season, haviJJg at least ten times as much rain in the wettest mont h as in the driest, equated with Et·ergreen and Semiet·ergreen Seasonal Forest.

The Koppen ~ystem perhaps is useful fo r a large-scale generalized map, but it is not very useful for small areas or for detailed vegetation mapping. Also, one cannot equate vegetation types with Koppen macrocli mates on a one-to-one basis. Holdridge Life Zones

Holdridge and Budowski (1 956, 1959) have produced a Life Zone map of Panama (Fig.4). Holdridge's life zones are based on the ratio between potential evapotranspiration and average total annual precipitation, and they are equated with gross vegetation formations. Their map gives six life zones and two transition zones for Panama: Tropical Moist Forest, Tropical Dry Forest, Subtropical Moist Forest, Lower Montane Wet Forest, Mon tane Wet Forest, Tropical Moist Forest (Transition), and Tropical Dry Forest (Transition).

According to Holdridge and Budowski, the areas of transition between two life zones generally are not extensive enough to be mapped. Bu t in those areas where there are gradual shifts in temperature or precipitation, broad transition zones can be recognized, as they have done in eastern Panama. Both the Koppen and Holdridge systems ignore edaphic, anthropogenic, physiognomic, and flo ristic factors. However, it must be recalled that Koppen's system primarily attempts to delimit climatic zones, not vegetation per se. Like the previous map (Fig.3), this map (Fig.4) does not show the vegetation actually occurring in each area, but it gives the gross plant formations that ideally should occur in a given area.

TH E VEGETATION OF I' ANA MA: A REVIEW

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Human influences

Unfortunately, the information on which the Koppen and Holdridge systems are based is lacking for much of Panama. Be that as it may, vegetation cannot be mapped from environmental parameters alone, no mal!er how much cl imatic informat ion is avai lable. The way to map vegetation is to go into the field and look at it. One investigator who has done just thi s is Bennett (1968), who is noteworthy for assessing the impact of man on the vegetation of the Isthmus. Bennett's thesis is that man has had a profound effect on the vegetation as long as he has been in Panama.1 In the past this effect was greatest at the time of the Spanish Conquest, when the population was approximately what it is now. The Indian population, drastically reduced by disease and slavery, has slowly been replaced by various ethnic groups until Panama's population again approximates what it was 500 years ago. H uman pressures on the environment also have varied with the population. Bennett recognizes a number of vegetation types for Panama (Fig.5). Mature Forest is forest that has had only mino r or intermittent disturbance by man ; Old Forest is now growing where records indicate previous important disturbance, but it is now little used; and Disturbed Forest is presently being disturbed by various forms of exploitation. Low Trees andfor Shrubs occur where there are disturbed conditions due to fire, overgrazing, and associated edaphic changes. Thorn-scrub and Cacti a re not due to man, climatic and edaphic factors apparently being of primary importance, although fire also may be involved. Sat>anna is found in areas where t here is marked disturbance; such areas would normally support forest. Grassy Plains would support scrub if left unburned. Grass and/or Sedges on Steep Slopes apparently are due to fire 1

For further information on this subject, see the excellent book by Sauer (1966).

174

D. M. PORTER

T HE VEGETA TION OF PANA M A: A REV IEW

175

A s ummary of plant commun ities

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In the absence of a detai led vegetati on map for Panama , the fo llowing is a step toward such a goal. Studies on the biology or the isthmus often have mentioned species and thei r abunda nce in given planf comm unities. The lists that fo llow at tempt to use contem porary nomenclature for the species ci ted and to p rovide equivalents for the comm unity na mes used in the original p ublications. H owever, no attempt has b.een made to provide equivalents for the original terms or relative abunda nce. The commu ni tic~ arc listed in order o r: (/) decreas ing disturba nce (Incipie nt F o rest, Early Second ary f o rest, La te Second ary F o rest); (2) decreas ing xericity (Li ttoral f orest, Thorn Forc"St, Deciduo us Seasonal F o rest, Savann a); (3) decreasing salinity (Saltwater Swamp forest, Saltwat er Riparian F o rest, Brackish Swamp Forest, Brack ish Riparia n F orest, Freshw ater Ma rsh, F reshwa ter Swamp Forest, freshwa ter R iparian Forest) ; a nd (4) increasing rainfall a nd increasing altitude (Monsoon Forest, Evergreen Seasona l fore st, Premon tane Rain forest, Cloud Forest, Elfi n Forest) .

Incipient .forest

F ig.5. Phytophysiognomic map of Panama. (After Bennett, 1968.)

and would support fo rest or scrub if unburned . Galeria Forest is simply forest a long rivers tl1at has not been cut, unlike the su rrounding area. Banana Plantations are self-explanato ry. Bennett 's map is t he best yet produced that represen ts the actual vegetati on of the entire isthmus on a large scale. Unfortu nately, however, it is no t precise enough to be used on the local level.

Darien forest types The most detailed vegetati on map on a large scale yet p rod uced for Panama is D uke's map of t he forest types of D arien (Duke and Porter, 1970). This map resulted from studies initia ted by the Interoceanic Sea-Level Canal Feasibi lity Study. Duke in the main has followed Beard's terminology in delimiti ng forest types (Beard, 1944, 1953, 1955a,b). Unlike most o ther vegetati on maps of Panam a, much of this map has been verified by intensive field studies on the ground . Unfortu nately, sufficien t information still is not availab le to produce such a detailed map of the plant commu nities of the entire Isthmu s ofPana ma.1 1 Duke's map originall y appeared in a publication of limited circulati o n. It will be published in the Annals of the Missouri Botanical Garden.

[Duke and Porter (1970), Darien]: frequent trees:

Carim papaya L. Coch/ospel'llwm ••itifolillm (Willd.) Spreng. Cocos 1/llcifera L. locally dominan t shrubs:

Mull/ ingia ca/abura L. frequent shrubs :

Acalypha macrostachya Jacq. Cestmmlati/olillm Lam. C/ibadiumleiocarpum Stectz. Lantana camara L. L. tri/olia L. Leandro dichotoma ( D. Don) Cogn. Manihot esculenta Crantz Neurolaena Iobato (L.) R. Br. Piper aduncum L. Pothomorphe peltata (L.) Miq. Rolandrafruticosa (L.) 0 . Ktze. Solanwnllirttmt Vahl Struchium sparganophorum (L.) 0. Ktze. Vemonia canescens H .B.K. V. patens H.B.K. locally dominan t banana-like o r small palmlike plants: Heliconia latispatha Benth.

frequent banana-like o r small pa lm-like plants: Carludovica palmata Ruiz and Pav. Helicouia mariae Hook. f. Zea mays L. freq uentlianas:

Elc11sine indica (L.) Gaertn. Solanllmjanwicense Mill. Wulffia baccata (L. f.) 0. Ktze. locally dominan t vines:

Dioscorea spp. frequent vines :

Cissus rhombi/olio Vahl C. sicyoides L. Dalechampia tiliifolia Lam. Desmodium adscendens (Sw.) D C. D. canwn (Gmel.) Schinz and Thellung Eupatorium ir·esineoides H .B.K. E. macrophyllum L. E. microstemon Cass. E. odoratum L. Gurania coccinea Cogn. Mik ania guaco H umb. and Bon pl. Momordica clrarantia L.

176

D. M. PORTER frequent herbs :

1'1t:alyplw an·en.\'i.v l)oc

Al!emtllllheraficoidea (L.) R. Br. Asclepias Cl/ras.wivicll L. Bo11rreria/aet•is (Lam.) Grise b. Bro wal/ia wuericmw L. Cllpsicmu ji-11tesceus L. Ceurhms brownii Rocm. and Schult. C. eciliuattls L. Chamacsyce hirta (L.) Millsp. C.l1ypericifolia (L.) Small C. hyssopifolia (L.) Millsp. C. 1hymifo/ia (L.) M illsp. Coix /achryma-jobi L. Cypems dijfusus Vahl Dichromeua cilia to Vahl Digitaria sauguiualis (L.) Scop. Echiuoch/oa co/onm11 (L.) Link Eclipta alba ( L.) Haask. Eleutherauthera mdera/is (Sw.) Sch. Bip. Erechtites hieracifo/ia (L.) Raf. Erlcerou bonarieusis L. Fimbristylis miliaceo (L.) Vahl liyptis capita/a Jacq. H. savwmarum Briq .

H..<uat•eoltms (L.) l'oit. H . t•erticil/ata Jacq. Just ida pectoralis J acq. Lmlwigiu spp. (as Ju.uiaca ;pf1.) Oi'imwumicrantlwm Willd. Oryza sati•·a L. Pauimmmaximmu Jacq. P. pi/osum Sw. Po.rpalmu p/imtalum Michx. P. ••irgotmu L. Phj•l/outlms urinaria L. Polygala pouiculata L. Porophyl/um ruderale (Jacq .) Cass. Portulaca oleracea L. Pseudclwhantopus spicat11s (Juss.) Rohr. Smtvage:da erect(l L. Scoporio d11/d;· L. Sida glomertua Cav. S.pymmidata Cav. S. rlwmbifo/ia L. So/auumnigrum L. (s. 1.) Spilamhe.< ocymifolia (Lam.) Moore Synedrella nodi/fora (L.) Gaertn. Waltheria indica L.

[Johnston (1949), Bale tlill, San Jose Island, Panama (as "Grassland")]: dominant grasses:

Axonopus aureus Beauv. Trachypogon secundus (Pres!) Scribn. the most conspicuous secondary grass :

Panicum mdgci Roem. and Schul t. other herbaceous plants:

A eschynomene brasiliana (Poir.) DC. Andropogon bicomis L. A. brevifolius Sw. A.leucostachyus H.B.K. Aristida capillacea Lam. Axonopus centra/is Chase Blepharodon mucroJwlatum Decne. Bourreria /atifolia (Aubl.) Schum. B. parvifolia Meyer B. pumilia Standi. Bulbostylisjunciformis(H.B.K.) Lindman Calopogonium mucwtoides Desv. Centrosema pubescens Ben th. Chamacsyce hyssopifo/ia (L.) Small (as Euphorbia hyssopifo/ia L.) Clitoria rabigbzosa Juss. Coutoubea spicata A ubi. Crotalaria pilosa Mill.

Curculigo scorzoneraefo/ia (La m.) Baker Curtia tcnel/a (Mart.) Ch am. Cypems/favus (Vahl) Necs Desmodium augu.wifolium (H.B.K.) DC. D. barbatum (L.) Bcnth. and Ocrst. Dichromena ciliato Vahl Dioscorea sapindoides J>resl Eleplwntopus mol/is H.B.K. Eleutherrmthera mdera/is (Sw.) Sch. Bip. Habenaria paucif/ora (Lind!.) Re ichb. f. Hyptis lantauaefo /ia Poit. Ipomoea miuutif/oro (Mart. an d Gal.) House Kylliugia odorala Vahl Oplismenus burmannii (Retz.) Beauv. Paspa/ummulticaule Poir. P.plicatulum Michx. Phaseolus longipedunculatus Mart. Pterolepispumila (Bon pl.) Cogn. Sauvagesia tene//a Lam. Sc/eria micrococca (Liebm.) Steud. S . pterota Pres I Setaria lenox (L. R ich.) Desv. Sida linifolia Cav. S . spinosa L. Spirantlies orchioides (Sw.) L. Rich. Waltheria indica L. (as W. americana L.)

TH E VEGETATIO N OF PANAMA: A R EV IEW

177

[Standley ( 1928), a bandoned vegetable gardens about Balboa, Canal Zone] : weeds:

persisting garden plants :

Cordwms spp. Desnwdimn spp. (as Meibomia) Sidaspp.

Dio.,·corc'a spp. DtJiic/ros lab/ub L. /1ibi.1·ms esculemus L. Manihot esw lenta Crantz

Early Secondary Forest [Duke and Porter (1970), Darien]: locally dominant trees: Oc/n·oma pyrtu11ida/e (Lam.) Urb. Trema micrantlw (L.) Blume frequent trees:

Carica papaya L. Casearia niti<la (L.) Jacq. Cochlo>1Jertm/ln vitifolium (Willd.) Spreng. Cordia al/iodora (Ruiz. and Pav.) Roem. an d

Stmdlium sparganophomm (L.) 0 . Ktzc. Tollmcfortiu CllspidatCJ H .llK. Triam/iiiiCJ lrrpfJU/a L. Vemo11i11 conescens H.B.K. V. patcm H.B.K. locally dominant banana-like or sma ll palmlike plants: Heliconia latispatha Benth.

Schull.

Didymopcmax moroto/oni (Aubl.) Dec. and Planch.

Guawma ulmifolia Lam. He/iocarpus popaycu1ensi;· H .B.K . Luehea ;peciosa Willd. P.l'idium guajm•a L. Triplaris cumingitlllll F isch. and Mey. Vi;mia baccifera (L.) T r. and Planch. V.latifolia Choisy Zanthoxy/11m panamemc P. Wilson Z . setulos11m P. Wilson frequent shrubs:

Acalypha macrostachya Jacq. Cestmm latifolillm Lam. Clibadiw11 appressipilum S. F. Blake C.leiocarpum Steetz. Clidemia octona (Bonpl.) L. 0. Wms. Gonzalag1111ia mdis (Standi.) Stand i. Hamelia axillaris Sw. Hasseltiaf/oribmula H. B.K. lsertia haenkeana D C. Lantana camara L. L. trifolia L. Leandro dic/wtoma (D. Don) Cogn. Manilwt esculenta C rantz Miconia /acera (Boo pl.) Naud. Muntingia ca/ab11ra L. Neuro/aena Iobato (L.) R. Br. Piper adwzcam L. P. marginatum Jacq. Pothomorphe pe/ta/a (L.) Miq. Rolandrafruticosa (L.) 0. Ktze. Solanum hirtum Yah! S. rugosum Dunal

frequent banana-like or small palm-like plants: Car/udovica palma/a RLtiz and Pav. Hypan'henia nr/tt (Nees) Stapf Heliconia imbricotCJ (0. Ktzc.) Baker H . u1ariae Hook. f. Renealmio cerm111 (Sw.) Macbr. frequent lianas :

Byllneria oculeata Jacq. EleuJ·ine indica (L.) G acrtn . G11rania coccinea Cogn. Mucuna bracteata D wyer Pluyganocydia corymbo>·a (Vent.) K. Sch. Solmtwnjamaicense Mill. Wulffta baccata (L. f.) 0. Ktze. frequent vines :

Cissus rhombifo/ia Ya hI C. sicyoides L. Dalechampia tiliifolia La m. Desmodium camrm (Gmel.) Schinz and Thellung Eupatorium iresineoides H.B. K. E. macrophyllum L. E. microstemon Cass. E. odoratum L. E. sinclairii Bent h. Mikania guaco H um b. and Bon pl. M. micrantlza H.B.K. Momordica charantia L. Rlzynclzosia ca/ycosa Standi. Sabicea villosa Roem. and Schult. frequen t herbs:

Asclepias carassavica L.

D. M. PORTER THE VEG ETATION OF PANAMA : A REVIEW

/Jourreria lae.,is (Lam.) Grise b. Browallia amerit·mw L . Cyperus dij}imts Vahl Diciii'OIIIel/11ciliaw Yah! J:.clitJta alba (L.) Haask. Eleatlwrwnlwra mderalis (Sw.) Sch. Bip.

Eri.~teron bmwriensi~·

Fimbrist)•lis milia,·ea (L.) Vahl Hyplis :>'ffl'ilunanun Briq. Justieia peetora/is Jacq. Ocimummicralllfllmt Willd. Panicmumoxinmm Jacq. P. pi/os11m Sw. Pa1palum plicatulum Michx.

P. l'irgalflm L.

l'oruf'lryllllm ruderale (Jacq.) Cass. l'ril'lllappulucca (L.) Pcrs. p,,·cudelcplumtopus .1picatus (Juss.) Rohr. Scleria melalctl<'a Schlcchl. and Cham. S. ptemw Pres! Scoparia dulcis L Sida ~:lomemw Cav. S. pymmidura Cav. S. rlwmbifo/ia L. SpilaullrcsoC)'nll[o/ia (La m.) Moore Synedrella nudiflora (L.) Gaertn. Wa/tlreria indica L.

(Johnsto n (1949), San Jose Isla nd, Pan;un!t as " High Green Thicket"]: principal trees:

Cecropia spiuesccus L. (as C. araclmoidca Pittier) Cordia al/iudora (Ruiz a nd Pav.) Roem. and Schult.

C. bicolor DC. Hirtel/a americana L. Nectandra ge111/ei Lundell Pltoebejo/ms/oniiC.K. Allen Pilltccellobium rufcsceus (Bent h.) Pitticr Protium remufolium ssp. mcleodii (I. M. J_ohnsl.) Porter (as P. mcleodii I. M. Johnst.) Xylopiafmlescens Aubl. Zuelauia guidouia (Sw.) Britt. and Millsp. secondary trees:

Casearia commersoniana Camb. (as C. myrirmtfw T urcz.)

C. syfl•eslris Sw. Cordia panamcnsis Riley Cupauia fulvida Tr. and Planch. Didymopauax morolotoni(Aubl.) Dec. and Planch . Ficus citrifolia P. Mill. (as F. staud/eymia Dugand) Hasseltiaf/ oribuuda H .B.K. lserlia hae11keaua DC. Mico11ia argelllea (Sw.) D C. M. hyperprasiua Naud. M. insufaris G Ieason

ill. impetio/aris (Sw.) DC. kf. pteropoda Bent h.

emergent trees:

Schult.

Tabebuia pentaphylla (L.) Hems!. Zuelania guido11ia (Sw.) Britt. and Millsp. principal shrubs:

Ca/ea prunifolia H. B.K.

~ommon

179

D""ill" uspem (Aubl.) Benoist (as D . lucie/a Pres!)

vines:

Plrl')'gnuoc)'diacorymbosa (Vent.) K. Sch. Serj£mia ntmliueata Sauv. and Wright T~trm:era t•ulubilis L.

Amphilophitmt pauiculatum(L.) Kunth Anemopaegma urbimlalum (J:tcq.) DC. Armbidaea chim (Humb. and Bo n pl.) Veri. [Kenoyer (1929), Barro

Color~do

lslan!l, Canal Zone]:

pio neer

forest trees: Didymoptmax morotoloni (Aubl.) D ec. and A11eiba tibuurbou A ubi. Planch. Bombacopsis quinata (Jacq.) Dugand (as B . . Heliocarpuspopayaue11 sis H.B. K. fendleri Seem.) Luehea seemcmnii Tr. antll'htnch . B. sessi!i.1· ( Benth.) Pitticr Micouia argeurea (Sw.) DC. Cecropia /augipes Pinier Oclii'0/1/a pymmida/e (Lam.) Urb. (as 0. limoC. ablusifolia Bcrtol. (as C. mexicaua Hems!.) nemis Rowlce) Cordia al/iodom (Ruiz a nd Pav.) Rocm. and Sclteclea gomphococca (Ma rt.) Burrell (as AtSchult. raleagomphococca Ma rt.) Trema micralllha (L.) Blume

common vines:

Amphilophimn paniculaltm';'( L.) Kunth Auemopaegma orbicttlatum (Jacq.) DC. Bauhinia excisa (Griseb.) Hems!. (as B. rhomp.wnii I.M. Johnst.) Chiococca alba (L.) 1-l itchc. Cissus eros(l L. Rich. C. rlwmbifolia Yah! Cliroria porrobellensis Buerling Cnestidiummfescens Planch. Cunnams fJ"namensis G riscb. Dm·illa aspcra (A ubi.) Benoist (as D. Iucida Pres!) Dioclea altissima var. megacarpa (Ro lfe) Maxwell (as D. megacarpa Rolfe) D. rej/exa Hook .f. Gouania polygama (Jacq.) Urb. 1/ipf!Ocrarca volubilis L fliraea rec/inara Jacq . Maclwerium purptwascens Pittier Philodeudron erlansonii l. M. Johns!. Plwyganocydia corymbosa (Vent.) K. Sch. Se1jauia alrolineata Sauv. and Wright S. nesiles LM. J ohns!. Tetracera volubilis L.

[Johnston (1949), San J ose Island, Panama (as "Low Gray Thicket")) :

Cecropiapeltata L. (as C. araclmoidea Pittier) Cordia alliodora (Ruiz and Pav.) Roem. and

Lycoseris latifolia (Don) Uenth.

Callicarpa acwninala H .B.K. Cordia spi11esceus L. (as C. fermginea (Lam.)

[Standley ( 1928), Canal Zone]: land o n Atlantic side recently under cultivation, but now abando ned, trees and shrubs: Adeuariaf!oribmrda H.B.K. Ca/athea spp. Cecropia sp p. CIJ/wslcgia xalapensis (Bon pl.) D. Don Guazunra ulmifolia Lam.

Helicouia spp. Hclicteres guazunwefolia H. B. K. Iudigofera sujji'uticosa Mill. f.Aulana spp.

thickets on low hills between Colon and Catival: Solanum hayesii Fernald Vismia spp.

Late Secondary Forest [Duke and Porter (1970), Darien): frequent canopy trees:

Cm•auillesia platallifolia (Humb. a nd Bonpl.) H .B.K.

Ceiba pe111a11dra (L.) Gaerln. Temtillalia amazonia (J. F. Gmel.) Exell locally dominant trees:

Trema micrautlui (L.) Blume frequent trees:

Roem. and Schult.) Solanum exlensum Bitter

Casearia 11ilida (L.) Jacq. Didymoparrax moroto/oui (Aubl.) Dec. and

secondary shrubs: Dalbergia brownei (Jacq.) Urb. Gynerium sagiuatum (Aubi.) Beauv.

Guazuma ulmifolia Lam. Heliocarpus popayauensis H.B.K. Luelrea :.pcciosa Willd. Margarilaria nobilis L f. Psidium guaja"a L.

Hibiscus tiliaceus L.

Ocltroma pyramidale (Lam.) Urb. (as 0. limoneu-l'is Rowlce) Piperaurittmt H.B.K. Se1jauia spp. Trema micrarrtfra (L.) Blume Triumfctta spp.

Planch.

Vismia baccifera (L.) Tr. and Planch. V. Ia!ifolia Cho isy Zalltlrox_vlwrr pauamense P. Wilson Z. se/ulosum P. WiiSO!l frequent shrubs:

Clibadiwn appressipilum S. F. Blake C. /eiocarpum Steetz. Gonza!Cigwria rudis (Standi.) Standi. Hamelia axil/oris Sw. Hasseltiafioribunda H .B.K. l sertia lraenkeana DC. umtaua camara L. Manihot esculellla Crantz Miconia /accra (Bonpl.) Naud. Neurolaena looora (L.) R. Br. Piper aduncum L P. margiuatum Jacq.

180

D. M. PORTE R

Potlwmmplte pdtata (L .) Miq. Solanum rugusum D unal Tourm:fortiacuspidma 1-I.IJ. K. Triumfella /appula L.

l:upatorium bi//bergillllll/11 Lie uri. E. iresim:uides 1-I.LI.K. E. /llti!TU[Ih)'ll/1111 L. E. micwstemuu C.tss. E. odomtwn L. locally dominant banana-like or small E ..riuclairii 13cnth. palm-like pla nts: Gumnia cocciuea Cogn. Hclicouia latispatlta Llcnth. Mikaniaguaco Humb. and llo npl. M.mit:rCIIIIhaH.l3.K. frequent banana-like or smajl palm-like · Rlty11tho.ria C11lycosa Standi. plants: S(tbicea vil/oso Rocm. and Schull. Helicouia i111bricma (0. Kt zc.) Llaker H .mariae Hook. f. frequent herbs: }fyparrhenia rnf(• (Nccs) Stapf Asclepias cur(W'aviw L. Reuealmia cermw (Sw.) M acbr. Baurreria laevis (Lam.) G riseb. Cyperus diffitsus Vahl Dichromeua cilia/a Vahl frequent lianas : Byttueria acu/eata Jaeq. Eclipltl alba (L.) Haask. Eleusiuc indicct (L.) Gaertn. Eleutheralllltera mderalis (Sw.) Seh. Bip. Mucuna bractea((l Dwyer Erigeron bouariensis L. P/u·ygcmocydia cory111bosa (Vent.) K. Sclt. Panicum maximum Jacq. Wulflia batCl/((1 (L. f.) 0. Ktze. Paspaltmt plicatulum M ichx. P. virga/11111 L. Prit•a lappulacea (L.) Pers. freq uen t vines: Cissu.1· rho111bi[olia Vahl Sclcria111elalcuca Schlecht. and Chanl. C. sicyoides L. S. plerola Prest Desmodiu111 cauu111 (Gmel.) Schinz and Thellung [Johnston (1949), San Jose Island, Panama (as ' 'North Forest")]: principal canopy trees:

Andira inermis (Wright) D C. Byrsaninw crassifolia (L.) H .B.K. Cordia alliodom (Ruiz and Pav.) Roem. and Schult.

C. biro/or DC. Hirtcl/a americana L. Ilexguianensis(Aubl.) 0. Ktze. Miconia argentea (Sw.) DC. Pem arborea Mulis Pltoebejo/mstonii C. K. Allen Pithcccllobiwu rufescens (Bent h.) Pittier Prolium /cnuifolillm ssp. mcleodii (I. M. Johnst.) Porter (asP. mcleodii L M. Johnst.) Temstroemia tepezapa/e Schlecht. an d Cham. (as T. semamtii Tr. and Planch.) Xylopiafrutescens A ubi. secondary canppy trees:

Annona purpurea DC. A. spraguei Saff. Bombacopsis sessilis (Benth.) Pittier (as Bombax sessile (Benth .) Bakh.) Coussapoa panamensis Pittier Didymopanax moro/otoni (Aubi.)Dec. and Planch. Ficas bullenei I. M. Johns!. F. popcnoei Standi.

Ocotea rubrinerl'is Mez Spondias mombi11 L. understory trees and shrubs:

Amaio11a corymbosa H .B.K. Calyeo/pus warszewicziamts llenl,. E11genia origanoides Berg Hirlella mcemosa Lam . (as H. oblongifolia D C.) Myrciaria jloribwufa (Willd.) Berg (as M. oucillii (Lundell) I. M. Johns!.)

Ouratea lncens (H.B.K.) Mart. (as 0. gaalemalensis Engl.) common vines:

Amphilophiam paniculatum (L.) Kunth Anemopaegma arbiculatum (Jacq.) DC. Arrabidaca pachycalyx Sprague Bauhinia excisa (Griseb .) Hems!. (as B. tlwmpsonii I. M . Johns!.) Chiococca alba (L.) Hitchc. Cissus rhombifo/ia Vahl Clitoria portobellensis Beurl. Cnestidium panamensis G riseb. Connarus rufescens Planch. Davilla aspera (Aubl.) Benoist (as D. Iucida P rest) Dioc/ea rej/exa Hook. f.

THE VEGETATION OF PANAMA: A REVIEW

DoliowqJIIs den/1111/.1" (Aubl.) Standi. Forl·temnia o•iridt•.\·cen.\· lllakc Gouania palygtmut (Jacq.) U rb. Hiraea redinaw J:1cq . klaclwerinm purpm·a.I'I'CI/.1'Pitticr Philodendron erlcmsunii I. M . J ohnst. P. gumemalense Engl.

lS I

Phr)'J:t/1/ocydia corymbo.m (Vent.) K . Sch. Securitlaca tlirer.•ifolia (L.) Ll l;~ ke Setjtmianesites I. M. Johnst. Tetl'tlcera volubilis L. Tetmpteris tlh·colot· (Meyer) DC. · T . macromrpa I. M. Johnst.

[Johnston (1949), San Jose Island , Panama (as "South Forest")]: principal canopy t rees:

Andira iuennis(Wright) DC. Byrsonit;ta cra.uifolia (L) H .B.K. Cassipourea el/iptica (Sw.) Poir. H irtella americana L /lex !llliauensis(Aubl. ) 0. Ktze. Pem arburea M utis PhvcbejolmstouiiC. K. Allen · Pouleria calllpcdtiaua (H.B.K .) Bachni Protium teuuifolium ssp . mc/eodii (1. M. Johnst.) Porler(as P. mc/eotlii I. M. Johns!.) Roupa/a monlana A ubi. (as R. complicala H.LI.K.) Temstroemia seemmmiiTr. and Planch. Xylopiafrutesceus A ubi. secondary canopy trees :

Bambacopsis sessilis (Bent h .) Pittier (as Bomba.\· sessile (llcnth.) Bakh.) Cordia bicolor DC. Coussapoa panamensis Pittier Didymopauax 111orototoni (Aubl.) Dec. a n d Pla nch.

Ficus bullenei l. M. Jo hns!. Maui/kara cltic/c (Pit tier) Gilly Micauia argenlea (Sw.) DC. Ocotea rubrinervis Mez

Zuelrmia guitlonia (Sw.) Brill. and Millsp. understory trc<.-s and shn1bs:

Anwioua corymbosa H.B.K. Calycolpus warszewiczimms Dcrg Eugenia ariganoides Berg Hirtella mcemosa Lam. (as H. ob/ongifolia DC.) il'ly•·ciaria flvribwula (Willd .) Berg (as M. oneil/ii (Lundell) l. M. J ohnst.) Oumtea lucens (H.D.K.) Mart. (as 0. gnlltemalen.l·is Engl.) common vines:

Cltiococca alba (L.) Hilchc. Cnestidium rufescem Planch. Comtams panamensis Griseb . Davilla aspera (Aubl.) 13enoist (as D. Iucida Pres I)

Doliocarpus delllatus (Aubl.) Standi. Gouaniapo/ygm1w (Jacq.) Urb. lfi{Jpocratea t'olubilis L. Philodendron erlansonii I. M . Johnst. P. gualemaleuse Engl. Se('llridaca dio•ersifolia (L.) Blake Tetracera I'Oiubilis L.

[Kenoyer (1929), Barro Colorado Island, Canal Zone (as "Older Pioneer Forest" and "Mixed Secondary Forest")] trees and shrubs :

Castilla elastica Cerv. (as C. panamensis Cook) Coccoloba spp. Ficusspp.

Gus/a via superba (H.B.K.) Berg Ingaspp.

lianas:

Bauhinia exci.ra (Griseb.) H em s!. climbing bamboos:

Artltrostylidium racemiflorum Steud. Clmsquea simplicifolia Munro

Melastomataceae

0/media aspera Ruiz and Pav. Pal mae

Poulsenia anna/a (Miq.) Standi. (as lnophloem armatum (Miq.) Pittier Protium spp. Sapium s pp.

Zanthoxylum spp:

plan ts of forest floor: Commelinaceae Filicinae M arantaccae Se/aginella spp. Xiphidium caeruleum Aubl. Z ingiberaceae

182

D. M. PORTER

THE VEGETATION OF PANAMA: A REVIEW

IS3

Littoral Forest

Conliaptmamellsis Riley

[Duke and Porter (1970). Darien ):

Eugenia origauoides Berg Gcnipa mucrica11a L .

Bromeli11 karatas L.

G11aZ1111ia lllmilola Lam. Guettarda odumta Lam. L11ehea candida (DC.) Mart. and Zucc. Matlt)•ba f!/aberrima Radlk. Plumcritl mbm L. Psidium guineensc Sw. Stemmadenia grandiflora (Jacq .) Miers Tabebuia pelltaplty/la ( L.) Hcmsl.

Cissus .•icyorifes L. Dim·lea altissima var. megacarpa (Rolfe) Maxwell (as D.megacarpa Rolfe) Marsdenia margaritaria R. C. Foster Odontocaryanitida Riley

locally do111inant 1rces:

Ena/lagmalaflfolia (Mill.) Small Hibisws tilit~ccus L. Tecoma stans (L.) H .B.K. Termiua/ia cawppa L. Xylo.mw pmwmeusis Turcz. frequent trees: JJucida bucera.1· L. Coccoloba uvifera (L.) L. Cocos nucifera L. Hippomnne ninucinelln L. Plumeria mbrn L. locally dominant shrubs:

Cluysoba/auus icaco L. Morindn pmromensis Seem.

l ttCtJIIinia sp. frequent lianas:

Combrelum decmulrum Jacq. loca lly dominant vines:

lt>omoea pex-caprae (L.) Roth. Wetle/ia trilobata (L.) Hitchc.

·I

frequent vines:

Ctmavnlit1maritimn (A ubi.) Thouars Me/authera aspera (Jaeq .) L. Rich. Vigna luteola (Jacq.) Bent h. locally dominant herbs:

S tachylllrphetajamaicensis (L.) Yahl

in shelter of thicket:

large vines:

[Standley (1928), C aribbean side of the Canal Zone: as "Strand Vegetation" ): shrubs:

herbs:

Caesalpinia crista L. Coccoloba uvifera (L.) L. Do/bergin ecastophy/la (L.) Tau b. Omplwlen diandrtt L. Xy losma prmamensis Turcz.

Croton puncta/us Jacq. Ky/lingia peruvitmn Lam. K.ptmgensVahl Pancratium litlom/e Jacq . (as Hyme11ocallis americana (L.) Stand i.) Philoxerus vermiculat"is (L.) R. Br. Vigna h1teo/a (Jacq.) llcnth. (as V. repcns (L.)

frequent herbs: frequent s hrubs:

Capparis cynoplwlloplwra L. Chiococcn alba (L.) Hitchc.

Cenchru.r ecliinatlls L. Eragrostis amabilis (L.)"Wright and Arn. Philoxerus 1•ermicularis (L.) R. BJ-.

vines:

Cnllltl•alia maritima (A ubi.) T houars Ipomoea pes-caprac (L.) Roth.

O.Ktze.)

[Johnston (1949), San Jose Island, Panama (as "Beach Vegetation")): cha racteristic trees of sandy beaches: Cocos mtcifera L. Couocat·pus erecta L. Hippomane nwnciue/la L. much less common trees on upper parts of sandy beaches : Elaeodemlrou xylocarpum (Vent.) D C. Ficus trigona/a L. (as F.leaveusii I. M. Johnst.) Lonchocarpus peutapltyl/us (Pa ir.) DC. Ximeuia americana L. most common herbs confined to stabilized beach sand: Canavalin maritima (Aubl.) Thouars (as C. rosea (Sw.) DC.) Ipomoea pes-cnprne (L.) Roth. Pancratiumlittorale Jacq. PhaseolusndennntlwsG. F. W. Mey. Uttiola pittieri Hack. Vigna luteola (Jacq.) Benth.

dense thickety growth at head s of many sandy beaches, (!)principal shrubs: Dalberf{io brownei(Jacq.) Urb. Hibiscus tiliaceus L. Tecoma stan.< (L.) H.B.K. (2)vines and scramblers:

Caesalpinia crista L. (as C. bondnc (L.) Roxb.) Entada gigas (L.) Fa we. and Rendle Heteropterys mncrostacltya Juss. Mucuna mutisiatta (H.D.K.) DC. M. sloanei Fa we. and Rendle Omphalen diaudra L. (as 0. pauamemis (Beurl. I. M . Jo hnst.) sheltered shingle beaches:

Avicenuia germinatts (L.) L. (as A.ttitida J acq.) Cottocarpus erecta L. Lagunculnria racemosa (L.) Gaert n. f. Sporobolus virginicus (L.) Kunth

[Johnston (1949), San Jose Island, Panama (as "East Harbor Thicket")): trees and shrubs:

Apei!Ja ti!Jourbou A ubi. Aulomyrcia tomenlosa (Aubl.) Amsho ff (as Myrcia tomentosa (Aubl.) DC.) Bombacopsis quinata (Jacq.) D ugand (as Bombax· quinatum Jacq.)

Buncltosia cornifolia H .B. K. Bursera simaruba (L.) Sarg. Cnesalpinia eriostac/rys Benth. Casearia uitida (L.) Jacq. (as C. bauquitana Krause)

Cochlospermum vitifolium (Willd.) Spreng.

Thorn Forest [Duke and Porter (1970), Darien]: locally dominantlianas:

Caesalpinin crista L.

[Bennett (1968): as " Thorn-bush and Cactus"]: some of the many taxa present:

Act1cia spp. Acamltocereus pemagonus (L.) Britt. and Rose Hamelin spp.

Oenocarpus spp. Prosopis sp.

[Holdridge and Budowski (1956): as "Tropical Dry Forest", association on poorer soils] :

Acaciafamesiana (L.) Willd.

Prosopisjulijiora (Sw.) DC.

[Johnston (1949), San Jose Island, Panama: as "Rocks and Islets Close to Shore"]: trees:

Bombacopsis quina/a (Jacq.) Dugand (as Bombax quinatum Jacq.) Bw·sera simarubn (L.) Sarg. Coclt/ospermum vitifolium (Willd.) Spreng. most frequent shrubs:

Colen prunifolia H.B.KGuettarda odorata (L.) Lam. Plumeria rubra L. succulents:

Acanthocereus pentagonus (L.) Britt. and Rose (as Cereus pentngonus L.)

Agave panamena T rel. Bromelia karatas L. Hylocereus polyrhizus (Weber) Brill. and Rose (as Cereus costaricensis (Weber) Berger) Opunlin elatior Mill. herbs:

Aeschynomene americana L. A_ brasiliaua (Poir.) DC. Andropogon angustatus (Presl) Steud: A_ brevifoliusSw. Anemia pastiuacaria Prantl

Til E VEGET ATION OF PANAM A: A REVIEW

D. M. PORTE R

I H4

Axolloprr.,· wpillal'is (Lam.) Chase 8/etio prrrpurc•a (Lam.) DC. Borrrrl'l'ia de11sij/om DC. B. lorijiJ/io (Aubl.) Schum. /J . ocymoides (Uurm .) DC. Bro.l·.,·m·olo 11odu.\'O(L.) Lincll. Colapogo11ium tmtculloide., Dcsv. Clwmaesycc ltypericifolia (L .) M illsp. (as E,pltorbio g/omifem (M illsp.) Wheeler) Clitoriombigino.1·o Juss. Corrtorrbea.lpicata Aubl. Cypems dif}ir.Wt.\' Vahl C./igrrlari,,· L. De.\'luodium barbatum (L.) Benth. and Ocrsl. Diclrromena ciliara Vahl Dioscorea sapindoides Prcsl El•oh•ulusfilipe.\· Mart. Ht1benaria panciflo•·(l (Lind I.) Rcichb. Hypti.1· pu/egoiodes Bentli. H .rectlrl•ata Poit . Jacquemontia tattmifolia (L.) Griscb. Kohlel'ia trrbif/ora (Cav.) Hemsl. Mamula amndinocea L.

Mitm cor[/11.\ /n·c·l·ij/llmsGmy Op/ismcnu,, lmrmwmii (Rctz.) Ucauv. J>onicum llwlleSw. Pectiselongoto H.II.K. Pepcromia pcllllcido (l.} l·l.U.K. Plwscol11s lollgipedmu·nlttttls Marl. Phyllcmtlws stipulotus (Ra L) Webster (as P. . dijJII.\'1/S Kl.) Polygololonxicoulis H.O.K . Polypodimn kulmii Fourn . Prerolcpis pumi/11 (flonpl.) Cogn. Rhyuchmpora micmmlw Va hl Sau1•agesia pulche/la Sc~m . S. tcue/la Lam. Schll'ackaea cuplwiode.1· (Ocnth.) Durand Scleria intermpra L. Rich. S. mict·ococc(t (Liebm.) Stcud. Setaria tenax (L. R ich.) Dcsv. Sit/a linifo/ia Cav. Spigelia tmthelmia L. Spiracamlw comifolia H.B.K. Sporobolus ci/iatn.r PresI Walt heria indica L. (as· W. americana L.)

large trees usually pr~scnt also :

o rher lrccs present in varying abundance:

' numcinel/a L. Hippoiumre Pisonia aculeata L. Prosopis julif/ora (Sw.) DC. (as P. chi/eusis

shrubs and small trees:

Acacia t'O.\'turicensis Schenck Cacraceae

Celtis iguanaeus (J acq.) Sarg. Er;•throxylou me.ricauwu H.B.K.

(Mol.) Stu ntz)

Deciduous Seasonal Forest [Holdridge and Budowski (1 956): as "Tropica l Dry Forest", association on good soils]: characteristic trees: Acromia patwmeusis Bailey (as A. sc!CI'ocmpa Marl.) Albizzia caribaea (Urb.) Brill. and Rose A. guachapcle (H.B.K.) Dugand (as Pseudosauumea guacltapele (H.B.K .) Harms) Apeiba tibourbou A ubi. Bombacopsisquinai a (Jacq.) D ugand Bume/ia sp. {?) Bursera simaruba (L.) Sa rg. Calycophyllum candidissinwm (Yah!) DC. Ceiba pemandra (L.} Gaerln. Cltloropl10ra tirrctoria (L.) G aud. Cocltlospemwm vitifolium (Willd.) Spreng.

vines:

Caescdpiuiu crios/achys Bc nrh. CochlosftCI'IIWIIIl'itifuliwu (Willd.) Spreng. Guazuma ulmifo/ia L. Luelteo candida (DC.) Mart. and Zucc.

Cis.ws siqoides L. most conspkuous low plant:

JJw me/ia kamtas L.

o ther woody planls frequenlly fo und:

herbs

Al/ophyllus occideutali.l' (Sw.) Radlk. Ca.l'earia 11itidt1 (L.) Jacq. (as C. bauquitmw Krause)

Cocco/oba corouara Jacq. (as C. waittii l. M. Johnst.)

Desmodiumll/l.lfiiSii[oliwn (H.D .K.) DC. Jacquemontia ta11mi[olia (L.) G riscb. Oplismena.\' brtrmmmii (Rctz.) Dcauv. Selaginclla diffusa (Prcsl) Spring Sic/a linifolia Cav. Tri{>sacwnlmrceolatwn Fourn. Walrlreria indica L. (as W. americana L.)

Savanna [Duke and Po rter ( 1970), Darien]: locally dominant lrces:

[Stan d ley ( 1928), rocks along I he Pacific shore, Panam{l : as ''Coastal T hicket"] :

Puuteria stipitata Cronq uis t Spmulitt.r JIIII'JIIIrea L. Su•tnmadcuiu gm udiflora (Jacq.) Miers

Bur.Hnt.riuwrulm (L.) Sarg. Spouclia., mombiu L.

Guettardaodomta Lam. Matayba glaberrima Radlk.

frequent banana-like or small palm-like plants: Hypt~rrhenia rufa (Nccs) Stapf

Anacarditwt occidentale L. Xylo{Jio aromuticu ( Lam.) Eichl. X,fmresccu.\· A ubi.

freq uent herbs: frequent trees:

Pmticummaximum Jacq.

Byrsauinw cra.uifolia (L.) H.B. K. Psidium guajm•a L. [Myers (1969), Santiago Plain, Veraguas: as "Cu/'({fella Savannas"]:

Cumtel/a americana L.

Didymopauax morolotoni (Aubl.) Dec. and [Bennett (1968): as " Grassy Plains"]:

Planeh.

Diphysa robiuioides Benth. and Ocrst. Enterolobitmt cyclocarpum (Jacq.) Griseb. Luehea carrdida (DC.) Mart. and Zucc. (?) Pitltecellobium samau (Jacq.) Benth. Platymiscium polystacltyum Seem. {As P. pimratum (Jacq.) D ugand) Prosopisjulif/ora (Sw.) DC. Sciadodendron excelsum Griseb. Simarouba glauco D C. Sterculia opera/a (Jacq.) Karst. S weetia panamensis Benth. Tabebuia chrysamha (Jacq.) Nicholson Xylopia frutesceus A ubi.

most frequent shrubs:·

Anacardittm occidentale L.

Byr.wuima crassifolia (L.) H.B.K. Cumtella americana L.

[Bennctt(l 968}: as " Low T rees and/or Oush"] : common shrub of drier phase:

Cumtella americana L. o ther c haracle ristic taxa :

Anacardirmt occiderrtale L. Byrsonima crassifo/ia (L.) H.B.K.

Nectandra s pp. Xylopia spp. abundant and frequent associate of shrubs:

Hyparrhenia rufa (Nees) Stapf

[Holdridge a nd Budowski (1956): as " Tropical Dry F orest", association on poorer soils]: [Johnston (1949), San Jose Island, Panama: as " Deciduous Forest" ]: fire-resistant species : common canopy trees: Cedrela augustifolia DC. (as C.fissilis Veil.)

185

occasional canopy trees : Bombacopsis quina/a (Jacq.) Dugand (as Bombax quinatum Jacq.)

Curatella americana L.

Xylopia.frutescens Aubl.

186

D. M.I'ORTER

T HE VEGETATIO N O F PANAMA : A REVIEW

[Jo hnston (1 949): S<1n rose Isla nd, Pan:una: as " Herbaceous Flora at East Harbor"]: trees :

Curatel/a tmu:riCll/111 L. herbs:

Acisalltilera quadmta Pcrs. Aeschynome11e amcricmw L. A. brasifit11w (Poir.) DC. Anemia pasli11acaria Prantl Audropogo11 llllgustatlls (Prest) Stcud. A. brevifolius Sw. Arislidujomllensis Kunth A. lemipesCav. Bletia purpurea (Lam.) DC. Bouneria dc11sif/ora DC. B.latifolill (A ubi.) Schum. B. ocymoidcs (Burm.) DC. Brtm avola 11odosa ( L.)'Lindl. Bt~clmera sp.

Calopogouitmtnwctmoides Dcsv. Cassia diphylla L. Cli!Oria rubigi11osa J uss. Couto11bea spicata Aubl. Crotoutriuitatis Millsp. Cypcms diffusus Yah ! C.ligularis L. C. tenerrimm· Pres! Desmodium barbttlll/11 (L.) Bent h. and Ocrst. Dichrome11a ciliata Yah! Dioscorea sapi11doides Pres! Eleoclwris illlerstichla (Vahl) Roem. and Schult. Evoll'ldus jilipes M art. Fimbrislylis amwa (All.) Roem. and Schult. Habcllariapaaci/lora (Lind!.) Reich b. f. Hyptis pulegioides Bent h. H. recurvata Poi!. Jacquemoutia tamnifolia (L.) Griseb.

Saltu·ater S wamp Forest

Kollleria lubiflum (Cav.) Hans!. Lep!Ochloaji/iformia (L'Im.) Ocauv. Mamilla arwulinacea L. Mar>)'lliantlws dwmacdrys (Vahl) 0. Ktze. Mimosa pu.>·i/la Bent h. Mitracm]ms brevif/orlls Gray Op/ismemts bamumnii (Rctz.) Beauv. PauiCilllllllOIIe Sw. Pttspa/am clavalifemm Wright Pectis elougara H .B.K. Pcntarrlwphis scabra 1-I.B.K. Phaseo/us /ougipedancu/alus Mart. P. ste11olobas Standi. l'hyllautlms caro/iuensis Wa lt. P. stipu/atus (Raf.) Webster (as P. dif}imt;· Kl.) Po/yga/a bryzoides St.-H i!. P.laugicaulis H.O.K. Pterolepis pumila (Bonpl.) Cogn. Rhynclwspora armcrioides Pres! R. mexicaua Steud. R. micrautha Vahl Rolula mexicana C hmn. and Schlecht. Sauvagesia pulchella Seem. S. tc1tella Lam. Sc/wllesia gaianensis (A ubi.) Mal me Schwackea cupheiodes (Benth.) Durand Scleria illlerrupla L . Rich. S. micrococca (Liebm.) Stcud. S . setacea Poir. Setaria /enax (L. Rich.) Dcsv. Sida liuifolia Cav. Spigelia anthelmia L. Spiractmllw comifo/ia H .B.K. Sporobolas ci/iatas Pres! Wallheria indica L. (as W. americana L .)

[Duke and Po rter (1970), Darien]: locally dominant trees :

Lagu11cularia racemosa (L.) Gacrtn . f. Pel/iceira rhizoplwrae Tr. and Planch. frequent trees:

Posoqaeria lalifo /ia (Rudge) Roem . and Schult.

Curate/Ia americana L. Psidiam salutare (H.B.K.) Berg (as P. oerste· deanum Berg) herbaceous plants:

Buclmera spp. Cassia tagera L.

Tabebuia palnm·is Hems!. locally dominant ba nana-like or small palm-li ke plants: Baclris nwjor Jacq.

Rltizop/wra brc>·islyla Salvoza

[Standley (1928), Pacific side of Canal Zone : as "Mangrove Swamps"]:

Pelliceira rltizoplwraeTr. and Planch. [Standley (1 928), Pacific side of Canal Z one : as "Saline Flats"]:

Sesul'ium portulacastmm (L.) L.

Sporobolus >•ilgiuicus(L.) K un th

Saltwater R iparian Forest [D uke and Porter (1970), Darien]: locally do minant canopy·trecs :

locally don1i nant s hrubs :

Rltizoplwra breo•istyla Salvoza R. mangle L.

Rltizop/wra samocnsis ( Hochr.) Salvoza

locally dominant trees: Lagaucularia racemosa (L.) Gacrtn. f.

Conocarpas erecta L. Tabebaia pa/ustris Hems!.

frequent trees :

frequent shrubs:

freq uen t lianas:

Cilharexylam caadalum L. Plumeria rubra L.

Rhabdadeuia bi/lora (Jacq.) M uell.-Arg.

[Mayo Melendez ( 1965), D arien : as "Rltizophora brevistyla Salv. (Mangle Colorado) Asociaci6n"]:

Rltizopllora brevistyla Salvoza

Eupatorium amygdalinum Lam. Psidium sa/utare (H.B.K.) Berg (as P. oerstedeanum Berg)

Brackish S wamp Forest [Duke and Porter (1970), Darien]:

[Standley ( 1928) : hill at eastern end ofTaboga Island, Panama): stunted bushes on steep s lopes : Byrsonima crassifo/ia (L.) H.B.K.

frequent shrubs:

Conocarpus erecta L.

[Johnston (1949), San Jose fsla nd, Panama: as "Coastal Swamp Forests"]: flooded by sea wa ter at high tide: Pel/iceim rltizopltorae Tr. and Planch.

[Standley (1928), Ancon Hill, Canal Zone]: herbs and shrubs on steep grassy slopes : Curtia tenella (!Vfart.) Cham. Dec/ieuxia mexicona DC.

187

Clitoria guyauensis (Aubi.) Benth. Crota/aria pilosa Mill. (as C. ptewcaula Desv.) Cyperaccae

Eupatorium amygda/inw11 Lam. £volvulus s pp. Indigo/era /espedezioides H .B.K. Sida linifo/ia Cav. Tephrasia nitens Benth Zornia diphylla (L.) Pers.

locall y dominant canopy trees :

Mora oleifera (fr.) Ducke Rhizophora brel'istyla Salvoza R. mangle L. locally dom inant trees:

A>•iccnnia bicolor Sta ndi. A. gcrminans (L.) L. Laguucalaria racemosa (L.) G aertn. f.

locally dominant shrubs :

Molllrichardia m·borescens (L.) Schott

Rhizophora samoensis ( Hochr.) Salvoza frequent shrubs :

Conocarpus erecta L. locally dominant palm-like plants Bactris major Jacq.

banana-like or

locally dominant herbs:

Philoxerus vemlicularis (L .) R . Br.

small

D. M. I'ORTER

THE VEGETATION OF I'ANAMA: A REVIEW

[Mayo Melendez ( 1965), Darien: as •· A Pict'lmia gl'l'miurm.,· L. (Mangle Negro) Asociacion ''I :

-Anosticlwm aarcul/t L. A ••iceunitt germinal/.\' (L.) L.

Graminac Hdicouia spp.

lm:nlly do minant canopy trees:

Momriclull'lfia urhoresccn.v (l.) Schott

(Mayo Melendez (1965), Darien: as " Mora olcifera (Tr.) Duckc (Aicornoquc) Asociaci6n"]:

Aslrocaryum slaudlqmunl/ Bailey Campa guiaueusis A ubi. Diejfeubacltia sp. Graminac

Mora ofeiferu (Tr.) Duckc

Brackish Riparian Forest [Duke and Por ter ( 1970), Darien) :

Rltizopfwra bre•·istyla Salvoza

(Mayo Melendez ( 1965), Darien: as "Momriclwrdiaurbore.>cenv Asociacion"]:

Pacltim rtlftWiim A ubi. Posoqueria fati/olia (Rudge) Rocm. and Schu ll. PriOt·ia copai/em G riscb. Pterocarpu.> o}/iciualis Jacq.

[Holdridge and Budowski {1956) : as "Mangrove Swam1>s", Bocas del Toro): swamp fringe:

Rftizopftora mangle L. area toward dry land:

A t•iceuuia germiuaus (L.) L.

frequent sh rubs: loca lly dom inant trees: Laguucularia racenu1.1a (L.) Gacrtn. f. Rapftia /aedigera Mart.

Rftizop!wra ma11gle L.

[Johnston (1949), San Jose Island, Pananui: as "Coasta l Swamp Forests"]: d omi nants where nooding with sea-w<11er is shallow or infrequent: A••icemtia bicofor Standi. A. germiltam·(L.) L. (as A. nitida Jacq.) Laguncufaria racemosa (L.) Gaertn. f. areas Hooded by brackish water: 1'Vlora oleifcra (Tr.) D ucke

Montriclwrdia arborcsccus (L.) Schott Pterocarpu.1· officina/is Jacq. frequent in shallowly flooded brackish swamp soi Is: Acrosticlumt aureum L. Euallagma fat!f'olill (L.) Small Rlwbdadenio bi}lora (Jacq.) Mueii.-Arg. Tabebuia palustris Hems!.

[Standley ( 1928), Canal Zone : as "Mangrove Thickets", Caribbean side]: trees :

Avice1mia germinotts (L .) L. (as A. nilida Jacq.) Conocarpus erecta L. Laguncufaria mcemosa (L.) Gaertn. f. Rftizophora sp.

shrubs and trees of lesser abundance: Cassipourea elliplica (Sw.) Poir. Pat•onia spicata Cav. (as P. scabra (Vogel) Cifferri) Rhabdadenia biflora (Jacq.) Mueii.-Arg. (as R. paludosa (Yah!) Miers)

[Standley (1928), Cana l Zone: as "Mangrove Swamps", Pacific side]: marshes back of mangroves:

Acrostichum aureum L.

Cyperaceae Graminae

locally dominant banana-like or s111all palmlike l>lants: Gyuerium sagitlalwn (A ubi.) Bcauv.

Cil!ttm:x)'lwn caudatwu L. locally dominant shrubs:

frequent lianas:

Moulric!umlia arbore!>Cens (L.) Schott

Rfwbdttdenia bif/ora (Jacq.) Mucii.-Arg.

Freshwater .Marslt [Kenoyer (1929), GatLI!l Lake, Cana l Zone: as "Emerged Aquatic Association"] :

Acrostic!twn daucacfoliwn Langsd. and Fisch. Crinum erubesceus A it. Hibiscus somrius L. f.

Sagiluwia flmcifolia L. Typ!ta angusli/olia L.

(Kenoyer ( 1929), Gatun La ke, Canal Zone: as " Eroding Shores'']:

Begouia}ilipes Bent h.

Lycopodium cerm~11111 L.

Bryophyta

Musci

Gleic!teuia f/exuosa (Schrad.) Met!. (as Dicanop/erisflexuosa Schrad.) Ko!tleria tubif/om (Cav.) Hanst.

P!tyffantlws uimri L. Pit)'rogr·muma ca/omelauos (L.) Link Tiboucftina lougifolia (Vahl) Bail I.

level swamp periodically flooded by fresh water:

Conocnrpus creela L. Coutarea ftexmulra (J acq.) Schum.

frequent trees :

Laguucnlariaracemosa (L.) Gacrtn. f. pure stands in periodically inundated tidal swamps, DariCn:

R11.\tia uccidemafis(Bcnth.) Hems!.

Tabefmia penlap!t)·lla (L.) Hems!.

[Holdridge and lludowski (1956): as "Aicornoq ue Swamp Forests'', Darien] :

Mort/ o/eifera (Tr.) Ducke

IS9

[Kenoyer ( 1929), Gatun Lake, Canal Zone: as "Floating Aquat ic Association"]:

Cham keuo)'eri Howe Eicft!tomia azurea (Sw.) KLmth (as Piaropus t1zureus (Sw.) Raf.) Ludwigia ltefmiut!torrftiza (Mart.) Hara (as Jus-

siaca untaus Hum b. and Bon pl.) Nvtia stmtiotes L. Sal vinia auricula/a A ubi. Utricularia 1ltixla Barn h.

[Kenoyer ( 1929), Gatun Lake, Canal Zone: as " Marsh Shrub Association"]: Dalbet~t:ia

ecastap!ty/fa (L.) Tau b.

Momriclwrdia arboresceus (L.) Schott

[Kenoyer {1929), Gatun Lake, C a nal Zone: as "Sedge Association"]:

Cypemsgigameus Vahl C. luzu/ae (L.) Retz. Fuireua umbel/a/a Rottb. Gynerium sagillalwtt (Aubl.) Beauv. Hymeuac/me amp/exicaulis (Rudge) Nees Ludwigia oclova!vis ssp. sessilij/ora (Mich.) Raven (as Jussiaea stt}frulicosa L.) Nephrofepis biserrala (Sw.) Schott

Phragmites commwds Trin.

Rftyncftospora corymbosa (L.) B ritt. Scirpus cubensis Kunth Scleria eggersiaua Boeck!. (as S. pa/udosa K uoth) Tfte/yp/eris gougy/odes (Schk.) Small (as Dryopleris IJOitgy/odes Schk.) T. serra/a (Cav.) Alston (as Dryoptef'is serrata (Cav.) C. Chr.)

[Kenoyer (1929), Gatun Lake, Canal Zone: as "Stump Islands"):

Atrdropogon bicomis L. Boehmeria cy/indrica (L .) Sw.

Cfusiaspp. EcfitJta alba (L.) Haask.

190

D. M. I'O RTER

FiCIIJSpp. Filicinac O rchiduceac

Typha ang11.1tijiJ/ia L. Vigna vexillllla (L.) A. Rich.

T I-l E VEGETA TIO N O f' PA N AMA: A REVi EW

PoiOquerialattfolia (Rudge) Roem . and Schult. Quamribea astem/epi.1 l'illicr Q. bmcteolosa (Duckc) Cuatr. Q.plerocalyx Hems!.

[Kenoyer (1929), Gatu n Lnkc, Canal Zone: as ··water-lily Association" ]: frequent shrubs:

Nymplwra amp/a (Salish.) DC. (as Castalia amp/a Salisb.)

Cassia reticulattt Willd.

[Standley (1928): Gatun Lake, Canal Zone]: emergent vegetation:

C/adi11m jamaicense Cra ntz (as Mariscus jamaiccnsis (Crantz) Britt.) Cypcm sgigantcus Vah l Hibiscus somrius l . f. Hydro/ca >11inosa L. (as Nama >1Jino;·a (L.) 0 . K tzc.) Ludll'igia spp. (as Jussiaea spp.} Miumia argentea (Sw.) DC. Pluchca pttr{mrascens (Sw.) DC. Po/ygonum punctatw11 Ell. Potttederia cordata L . Sagittaria lancifolia L. aquatic vegetation: Ceratopteris sp. £chi11odorus sp. Eichhomia azurca (Sw.) K unth (asPiaropusazttreus (Sw.) Raf.) Le1111tlt cyclostasa (E ll.} Chcv. Ludwigia he/mintlwrrhiza (Mart.} I-lara (as Jus.<iaea natans Hum b. and Bon pl.} Nympftaea sp. (as Castalia sp.) NJ•mplwides lmmboldtia11a (H.B.K.) 0. Ktze. Pistia slratiotes L.

Safl.iniasp. Utricu/aria sp. [Stand ley (1928): boggy spots on savanna d uring rainy season, Panama]: Anagallis pwnila Sw. (as Centunculus pentandrus R.Br.)

Bacopa spp. Eriocaulon seemamtii Molden kc (as E. schiedea1111111 Koern.) Grami nae

flysantftes inaequa/is (Walt.} Pennell Lophotocat1JIIs sp. Marsileo sp. ivlayaca aubletii Michx. Safl.iuiasp. Sam•agesia pulchella Seem. [Standley (1928): open boggy land ncar Matias Hernandez, Panama]: Aesclt)•nomelle ltispida Sw. A. scnsitil'a Sw.

Habe11aria sp. -Koste/etzkya pe111asperma (DC.) G riseb. (as K. ;·agittata Pres!) Me/ochiome/issifo/ia Bent h. P!tylllmtlws stipulatw· (Raf.) Webster (as P. diffusus Kl.} Sclwltesia sp. Sesbauia emerus (A ubi.) U rb. [Standley (1928): treeless swamp near Pacific beyond Rio Tocumen, Panama!:

locally dominant banana-like or small palmlike plants: Bactris major lacq.

191

Corozo olcifera (H.B.K .) Bailey frequent banana-like or small palm-like plants: Rcnectlmia cemult (Sw.) Macbr. .

frequent herbs :

Limuoclwris /lava (L.) Ouch. NJ•mpltacablluulaG. F. W. Mcy. Panicttm11wxiuuun Jacq.

(Mayo Melendez (1965), Darien as " Prioria copai[eri1 G ris. (Cativo) Asociaci6n" l : trees :

Astrocaryum stamlleyamtm Bailey. Campa guiattettsis Aubl. Mora o/eifera (Tr.) Duckc Pcttlaclethmmacroloba (Willd .) 0. Ktze. Prioria copaifera Grise b. Pterocarpus o}ficirwlis Jacq. Tabebuia rosea (Bertol.) DC.

edged with dense shrubbery of:

Acrostic/111m aurc11m L. Dieffeubacltia sp p. . Enallagmalatifo/ia (Mill.} Small Graminae Helicottiu spp . Mora oleifera (T r.) Duckc

[Holdridge and Dudowski (1956): as "Cativo F orests", Darien]:

Campa guianeusis A ubi. Prioria copaifem G riscb.

Quararibea sp. -

[Holdridge and Budowski (1956) : as "Mauicaria Swamps", Bocas del T oro]:

Manicaria saccifera Gaertn. [Holdridge and Budowski (1956) : as "Orey Swamp Forests", Bocas del Toro]:

Campnosperma pmwmeusis Standi.

Symp!tottia globulifera L . f.

[Holdridge and Budowski (1956): as "Pacltim aquatica Aubl.

Canuasp.

Pac!tira aqualica A ubi.

Cyperaceae Graminae Lud,..igia spp. (as Jussiaea spp.) Thalia sp.

Pterocarpus officina/is Jacq.

~waonp

Forest", Rio Sambu, Darien]:

[Holdridge and Budowski (1956): as "Pterocarpus o.f/ici11olis J acq. Stands") :

[Standley (1928): as "Swamps amid Pacific Savannas", Panama]:

Freshwater Swamp Forest [Duke and Po rter (1 970), Darien]: locally dominan t canopy trees:

Pachira aquatica Aubl. Prioria copaifera Griseb. Pterocarpus ltayesii H ems!. P. o.ffici11alis Jacq. Tabebuia peutaphylla (L .) H ems!. freq uent canopy trees: Copaifera aromarica Dwyer

C. pauamensis (Britt.) Standi.

locally dominant trees:

Browueopsis excelsa Pittier Erytltrina glauca Willd. Rapltia taedigera Mart. frequent trees:

C/usiaspp.

more abundant and striking trees: Annona purpurea Dunal Byrsonima crassifolia (L.) H.B.K. Cassia moschata I-I.B.K. Cedre/a angustifolia DC. (as C.fissi/is Yell.) Coccoloba caracasaua Meisn. Enterolobium cyclocarpum (Jacq.) Griseb. Erythrina glauca Willd. lfymenaea courbaril L

l ngasp. Licania platypus ( Hems!.) F ritsch Luehea seemanniiTr. and Planch.

Nectandra globosa (A ubi.) Mez Pithecellobium saman (Jacq.) Bent h. Pseudobombax septenatum (Jacq.) D uga nd (as Bombax barrigon (Seem.) Decne.) Schee/ea zonensis Bailey (as Atta/ea gomp!tococca Mart.)

Sciadodendron excelsum Griscb. Sloanea temijfora (DC.) Standi. (as S. quadriva!vis Seem.) Sterculia apetala (Jacq .) Karst.

192

D. M. I'ORTER THE VEGETATIO N OF PANAMA: A REVIEW

Bauhiniu sp.

shrubs o r small trees: Xylopia spp.

Vi.l'miaspp.

[Standley ( 1928): as "Wooded Swamps", Caribbean side of Canal Zone]: trees:

Heli£wria sp p. Murantaccac

Manicaria spp. Prioria copaifem Griscb.

Rubiaceac Zingiberaceac

shrubs :

Broomea macropltylla Linden [Sta ndley (1928) : as "Wooded Swamps", cast of Rio Tapia, Pana ma]: plen tiful t rees:

Zantlroxylam sp .

Cedre/a arrgrt.\'tifuJia D C. (as C.jissi/is Yell.) Guarea guidonia (L.) Sleumer (as G. guara (Jacq.) P. Wilson)

frcquc11tlianas:

frequent vines :

Eupatorium iresineoides H.B.K. E. macrophyllum L. E. micro.rremon Cass. E. odoratrrm L. Garwria coci::irwa Cogn. Mikania guaco 1-lumb. and Bon pl. Momordica c/wrantia L.

f rcq uent herbs:

B/el'iwm pmwmensis Lindau Coix lac/uyma,jobi L. Eclrinoclrloa colotumr (L.) Link. Eclipta alba (L.) Haask. Justicia coma/a (L.) Lam. J."pectom/is J acq . Ludu•igia spp. Odontonema longifolium (Ocrsl.) 0. Ktzc. Paniwmmaximum J acq. Prio•a lappulacea (L.) Pcrs. Scoparia dulcis L. Tiboachina /ongifolia (Yah!) Bail!.

[llennctt (1968): as "Galeria forest"]:

Armbidaea pac/rycalyx Sprague

Lajimrsia punicifulia DC.

Sabicea o•illosa Rocm. and Schull.

Byt/1/eria aculeata Jatq. Mucuna bmcteara Dwyer Phryganocydia ~orymbosa (Vent .) K. Sch. Strycluros ptliWmensis Seem. Wu/jfra baccMa (L. f.) 0. Ktzc.

vines :

193

common taxa i ncludc: A1iacardium excelsum (Bertcro and Balbis) Skeels

Cecropia spp. Ficus spp.

Freslnrater Riparian Forest . [Holdridge and Budowski (1956): as "Tropical Dry Forest'' ]:

[Duke and Porter (1970), D arien]: locally dominant canopy trees : Prioria copaifem Griseb . Pterocarpa>· officina/is Jacq. Swartzia panamem·h llcnth. Tabebaia pelllaphylla (L.) 1-lcmsl. frequent canopy trees: Ficas insipida Willd. Pac/rim aqaatica A ubi. locally dominant trees:

Pithecellobiaror/ongifo/iam (Humb. and Bon pl.) Standi.

Raphia taedigera Mart. freq uent trees :

Astrocarywn standleyanam Bailey Cecropia /ongipes Pittier C. obta.I'Jfolia Ber tol. C.peltata L. Clromelia spinosa Jacq. Clusia spp. Cocco/oba acuminata H.B.K. Geoffi·oea inermis Sw. Gustavia superba (H.B.K.) Berg. Jnga puncta/a W illd. Luehea seemanniiTr. and Planch. Myrcia sp/endens (Sw.) DC. 0/media aspera Ruiz and Pav. Pentac/ethra macro/oba (Willd.) 0. Ktze. Pithecel/obium rufescens (Benth.) Pittier Triclranthera gigantea (Hum b. and Bon pl.) Nees

Waruewiczia coccinea (Yah!) Klotzsh. locally dominant shrubs:

Lindenia rio•alis Bcnth. frcq uent shrubs :

Cassia reticu/ata Willd. Chiococca alba (L.) 1-l itchc. Clibadiwrrleiocarpwn Stectz. Gonza/agwria mdis (Sta ndi.) Standi. I-Im·seltia/loribwrda 1-l.B.K. I-fenriettclla fascicularis (Sw.) Tr. Lturtana camara L. Leamlm dic/rotoma (D. Don) C~gn. Mabea occidenta/is Bent h. Mimosapigra L. Ncurolaena Iobato (L.) R . Br. Odontonema strictum (Nees) 0. Ktze. Palicourea guianensis A ubi. P. triphyl/a DC. P:,yc/ootria lwrizontalis Sw. R icinm· communis L. Siparuna guianensis A ubi. Triumfetta lappa/a L. locally dominant banana-like or small palmlike plants: Gynerium sagittatum (Aubl.) Beauv. Phytelephas seemarmii Cook frequent banana-like or small palm-like plan ts: Re~~ealmia cernua (Sw.) Macbr.

along streams or on alluvial fiats next to rivers where water table is high:

Arwcardiam excelsrmr (Bertero and

Balbis)

Skeels

[Standley (1928), tributaries of Rio.Jlaraiso near East Paraiso between Summit and Pedro Miguel, Can a l Zone]:

Tristiclria trifaria (Willd.) Tul. (as T. hypnoides

in great abundance:

(St. H i!.) Spreng .)

Monsoon Forest fOuke and Porter (1970), Darien]: locally dominant canopy trees:

Anacardium exce/swn (Bertero and Balbis) Skeels Cal'anil/esia p/atanifo/ia (Humb. and Bonpl.) H .B.K.

Ceiba pentaru/ra (L.) Gaertri. frequent canopy trees:

• Bombacopsis quina/a (Jacq.) Dugand B. sessi/is (Ben th.) Pittier Enterolobium cyclocarpum (Jacq.) Griseb. Licania hypoleuca Benth. Platypodium elegans Vogel Pseudobombax septenatum (Jacq.) Dugand Ste/'cu/ia ape tala (Jacq.) Karst. Termina/ia amazonia (J. F. Gmel.) Exell Vitex cymosa Sp reng. V. masoniana P ittier locally dominant trees:

Mouriri parvifolia Benth.

frequen t trees:

Allophyl/as occidentalis (Sw.) Radlk. Alseis blackiana Hems!. Amaioua corymbosa H.B.K. Asrrocaryam stand/eyam11n Bailey Calycoplryllum candidissimum (Vahl) DC. Clramaedorea cf. pacaya Oerst. C. wend/andiana (Oerst.) Hems!. Chione chambersii Dwyer and Hayden Clwmelia recordii Stand!. C. spinosa Jacq. Clusiasp. Cnestidium rufescens Planch. Coccoloba darienensis Howard Cordia al/iodora (Ruiz and Pav.) Roem. and Schult.

Ficus nymplraefo/ia L. Guareaguidonia (L.) Sleumer Gustavio nana Pittier G. superba (H.B.K.) Berg. Heisteria /ongipes Standi.

194

D. M. PORTER

flirt diu ntccmosa Lam. Luchca secm{//miiTr. and Planch. Jvfacrocncmum g/abrcscens (Bcnth.) Wcdd. Mico11ia argeutca (Sw.) DC. M. burea/i~· G leason Myrcia splendens (Sw.) D C. Neca muplifulia D onn. Sm. Ouratea fucens (H.Il.K.) Engl. Pithece/lobium rufesceus (Bent h.) Pitticr Pusoqueria lattfolia (Rudge) Rocm. and Schult. Protium pauamense (Rose) I. M. Jo hns!. Quararibett astcro/epis Pittier Q. bracteolosa (Ducke) Cuatr. Randia armata (Sw.) DC. Saba/ a/leuii Bailey Schee/ia zuncnsis Bailey Siparww pauciflora (Beurl.) A. D C. Sorocea affinis HemsI. Stemmadeuia gmll(/if/ora (Jacq.) Miers Swartzia simplex (Sw.) Gacrtn. Trophis racemusa (L.) U rb. Xylopia aromatica (Lam.) Eichl. X. bocatorcua Schcry X. fmtesceus A u bi. locally dominant shrubs:

Faramea occidentalis (L.) R ich . Mabea occidentalis Bent h. Piper pinoganense T rei. frequent sh rubs:

AcalnJha diversifo/ia J acq. Alibertia edulis (L.Rich.) A. Rich. Aphelaudra sinclairiana Nees C/avija mezii Pittier Faramea luteovirens Standi. Hasseltiafloribunda H.B.K. Hebracautlms silvaticus Nees

1/emmia purpurco (Pittier) R. E. Schultes Leondra dichotumo (D. Don) Cogn. Nu:a laetivirens Sl:mdl. Palicoarea guiauensis A itbl. P. triphylla DC. Pipt'r dariencnsc C. DC. 1'. reticuk1tlllll L. Psyclwtria capitattl Ruiz and Pav. Quassia W1111ra L. frequent banana-lik e or small palm-like plants: H e/iconia meta/fica Pl. and Lit1den H. vagina/is Benth . Renealmia cenwa (Sw.) Macbr. Xiphidium caemleum A ubi. frequent lianas:

Comwmspmw11te11sis Griseb. C. wil/iamsii Britt. Doliocarpus de11taius (Aubl.) Standi. D. major Gmcl. Atfaclracri1m1 capote D ugand Mal'ipa panamemis Hems!. Passiflora vitifolia H.B.K . Roureag/ahra H.B.K. Tetracera ••o/ubilis L. Wu/flia baccata (L. f.) 0. Ktze. frequent vines:

Plriladendron gurtiferum Kunth

T H E VEGET ATION OF PAN AMA: A REVIEW

Cavanillesia plalanifulia (Humb. and Bon pl.) H.ll.K.

Ceiba penttmdm (L.) Gaertn. Gttstavia supetba (H.B. K .) Berg.

Cm•atrillesia p/atanifo/ia (Humb. and Bonpl.) H.B.K. [ Holdridge and Budowski ( 1956): as "Tropical Moist Forest'']:

Anacardirm 1excels1m1 (Bcrtero and Dalbis) Skeels Brosimwu spp. Carapa guiauensis A ubi. Cecropia obtusifo/ia Bertol. Centrolobium paraeuse var. oreuocensc Bcnth. (as C. patinense Pittier?) Coccolobatuercklreimii Donn . Sm. Couroupita dt1rienensis P ittier (as "C. panameusis") Dipteryx ptllwmem'is (Pitticr) Record

[Myers (1 969): as "Cava11illesia p/ata11ifolia Association", eastern Panama]:

Cava11illesia p/atanifolia (Humb. and Bonpl.) H.B.K. [Myers (1969): as "Flat Lowland F orest", cutover forest about Garach ine, Darien]:

Cava11illesia p/atanifolia (Humb. and Bonpl.)

~tze.

secondary trees: all primary and secondary species of the "North Forest" ( = Late Secondary Forest)

disti nctive secondary trees: (Jacq.) P. Wilson)

[Mayo Melendez (!965), Darien: as "Bosque Seconda rio Antiguo"] :

Bombacopsis quinata (Jaeq.) Dugand Cavm1illesia platanifolia (Humb. and Bonp l.) H.B.K.

Cedrela odorata L. Ceiba pentandra (L.) Gaertn. Swietenia macroplrylla G. King

[ Mayo Melendez (1965), Darien as "Cavanil/esia-Bosque Mixto Asociaci6n "]:

A11acardiam exce/sum (Bertero and Balbis)Skeels

Astrocaryum stand/eyanum Bailey

understory trees and shrubs:

ArdiJ·iacompressa H.B.K. mostly those found also in other forests on the island lianas: Bartl1inia excisa (Griseb.) Hems!. (as B. tlrompsonii r. M. Johns!.) alii ianas oft he" North F orest "(= Late Secondary Forest)

[Johnston (I 949), San Jose Island, Panama: a s " Streamside Forests"] : common characteris t ic trees : A11acardium excelsum (Bertero and Balbis) Skeels Ficus citrifolia P. Mill. (as F. duga11dii Standi.) F. insipida Willd. (as F. crii5siuscula Standi.) F. trigo11ata L. (as F. campbellii I. M . Joh nst.) Lica11ia platypus (Hems!.) Fri tsch Luel1ea seemam1ii Tr. and Planch.

Guar·ea guido11ia (L.) Sleu mer (as G. guara

H .B.K.

Gustavia sp. Herrtmia pmpurrea (Pitticr) R. E. Schultes (as Tlreobromapurpureum Pit tier) lri(ll-tea exorrl1iza Mart. Jacara11da copaia (Aubl.) D. Don Lecytlris sp. Lue/rea seemmmiiTr. and Pia ncb. Pentacletlrra macroloba (Willd.) 0. K tze. Viro/asp p. Warszewiczia cocci11ea (Vahl) Klotzsch.

[Johnston (1949), San Jose Island, Panama: as " Marino Forest"]: principal canopy tree: Tetragastris pa11amensis (Engl.) 0.

frequent epiphytes:

frequent herbs:

Quararibeu astcrolepis Pittier S11·m·tzia sp. Ummopsis pillieri San·.

[Hold ridge and Budowski ( 1956): as " Transition Forests"]:

Tillandsia kege/ia11a Mez Justicia pectoralis Jacq.

195

G. multiflora A. Juss. (as G. culebrana C. DC.) Gustavia superba (H.B.K.) Berg lnga spurea Willd. Mabea occidentalis Benth. Macrocnemum glabrescens (Ben th.) Wed d. Marila macroplryl/a Bent h.

Piperspp. Triclrallllrera gigalllea var. guia11eusis Gleason common palms:

Bactris ba/anoidea (Oerst.) Wend!. common vines:

Dieffenbacl1ia sp. Philodendron er/auso11ii I. M. Johns!. P./rarlowiii. M . J ohnst. common terrestrial bromeliad:

Aeclm1ea magdafenae (Andre) Baker epiphytes : most orchids known from the island occur here

196

D. M.I'ORT ER

TH E VEG ETATION O F PANAMA: A R EVIEW

(Kenoyer ( 1929), 13arro Colorado Island, Canal Zone ): climax forest dominants: Bombacupsis quina/a (Jacq.) Dugand (as B.fendleri (Seem.) Piu icr) · Cuumarounalwnamcnsis Piuier Ficus insipida Willd. (as F. glabrata H.B.K.) Grias fendleri Seem.

Hum crepitans L. l riartea exhorrhiza Mart. Jacarmula copaia (A ubi.) D. Don Platypodiwn elegans Vogel (as P. llwxonimwm l'illicr)

Prioria copaifera Grise b. Spondias mombin L. Sterculia apetala (Jacq.) Ka rst. Symplwnia glubulifem L. f. Tabebuiaguayacan (Seem.) Hcmsl.

Myrsin aceae

T. pentaphylla (L.) Hcmsl. Tenniua/ia amazonia (J . F. Gmcl.) Exell (as T. lwyesii !'ill ier) Viro/a sebifem A ubi. (as V. pauameusis (Hcmsl.) Warb.)

[Standley ( 1928): narrow belt of alluvial land bordering Rio Tapia and Rio Tocumen, Panama]: shrubs:

trees:

Auactmlium excelsum (Oertero a nd Oalbis) Skeels Dipterodendron costariceuse Rad lk. Pem arborea M utis Pithecellobimn longifolium (Humb. and Bonpl.) Standi. (as P. valrlianum Bent h.) Terminalia amazonia (J. F. Gmcl.) Exell (as T. lwyesii Pi!lier)

Sipanma paucij/ora ( B~u rl.) A. DC.

Apeiba tibourbou A ubi. Cavanil/esia platauifo/ia (Humb. a nd Bonpl.)

muddy forest a long streams: magdale~we (Andre) Standi.

and Calderon)

sticky red clay soil overflo wed at h igh water: Dict)•oxiphilllll sp. Dieffenbachia sp. Tectaria sp.

Ficusspp. Gliricidia sepium (Jacq.) Standi. Raupa/a montana Au bl. (as R. daricnensis Pittier)

H.B.K.

Cecropia spp. Cordia alliodora (Ruiz and Pav.) Roem. and

Triplaris americana L.

Schult. -[Standley (1 928): "as wet forests of A tlantic Canal Zone"] : large trees :

Andira inermis(Sw.) H.B.K. Castilla elastica Cav. (as C. panamensis C ook) Chrysophyllwn spp. Ficusspp. Oleiocarpol! panamense (Pittier) Dwyer (as Coumarouna panamensis Pittier) Pou/senia armata (Miq.) Standi. (as lnoph/oeum armatum (Miq.) Pittier) Protium spp. Virolaspp. Zanthoxylum spp.

Bignoniaccae ep iphytes: Araceae Bromel iaccae Filicinae Ord1idaceac

EFergreen S easonal Forest [ Duke and Porter (1970): Darien ]: locally dom inant canopy trees : Alwrardilllll excelsum (Bcrtcro and Balbis) Skeels frequent canopy trees :

tier below tallest trees: Cyatheaceae

Didymapanax morolotoni (Aubl.) Dec. a nd

Stcmmadeniagmmliflora (Jacq.) Miers Warszcwiczia coccinea (Yah!) K lotzsch. locally domina nt shrubs:

Bombacop.tis quill(lfll (Jacq .) Dugand B. sessilis (Benth.) l'ittier Brosim11111 guia11ense (Aubl.) Huber Ceiba pentandra (L.) Gaertn. Coclr/ospemurm williamsii Macbr. Myroxylon balsamum var. pereire (Royle) Harms Olciocarpon palwmense (Pittier) Dwyer

Acchmea magdalenae (Andre) Ba ker (as Ananas

[Standley (1928): vestiges of natura l vegetation on low hills about Corozal, Paraiso, and Summit Canal Zone]: Bombacaceae

lianas:

l'emagoni11 spp. I':.J•c/1otria spp. Qua.uiam11am L. Smilaxspp. Stryclr11os spp.

Zauthox)•lmu pmmmense 1'. Wi lson stream valleys: Araccae Cyathcaccae Danaea uodo.w (L.) J. E. Sm. Dieffeubachia ocrstedii Schott Gcsncriaccac Pa lmae Polypodiaccae Trichomanes diversifi·ons (Bo ry) Sadcb.

freq uent trees :

Clusiaspp. Cono:."legiaxalapensis (Bon pl.) D. Don. Ficus nymphaefolia L. Gustal'ia;·uperba(H.B. K.) Berg Heistcria longipes Standi. Luchea seemannii Tr. and Pla nch. Miconia borealis GleasonOenocarpus ponwnen1·is Ba iley Ourtrtea lucens (H. B.K.) Engl. Pentagonia bracl1yotis (Standi.) Standi. P. macrophylla Bent h. Pogonopus ;peciosus (Jacq.) Schlll\1. Posoquerialat({o!ia (Rudge) Roein. and Schult. Po1woumu scobina R . Ben. Sapindus saponaria L . Siparrma paucij/ora (Beurl.) A. D C.

Mabea accident a/is Dent h. frequen t shru bs:

Cephaelis glomcrrrlara Donn. Sm. Clm•ija mezii PittierFaramca luteavirens Standi. F. occidentalis (L.) Rich. Hasseltia/lorilumda H.B.K. Herrania p1upurea (Pittier) R. E. Schultes Letmdra dichotoma (D. Don) Cogn. M iconia oinocflropllylla Donn. Sm. Piper daricnense C. DC. P:.-yclrotria capita/a Ruizand Pav. Quassia amara L. frequent banana-like or small palm-like p lants: Costus nutans K. Sch. Heliconiametallica P l. and Linden Renealmia cemua (Sw.) Macbr. Stromllllthe lutea (Jacq.) Eichl. Xipllidium caemleum A ubi. freq uent lianas:

Passif/ara viti/olia H.B.K.

[Myers (1969), Cerro Sapo, Darien : as "Lowland H ill Forest (Evergreen Seasonal or Monsoon R ain Forest)"]: conspicuous understory dominant:

Phytelcphas sp.

Planch.

Gustavia superba (H. B.K.) Berg.

Premontane Rain Forest

Pal mae

[Duke and Porter (I 970), D arien]: thickets of shrubs and vines beneath trees:

Cestrum spp. Herrania purpurea (Pittier) R. E. Schultes (as Theobromapwpureum Pittier) Melastomataceae

197

frequent canopy trees:

Brosimum guianense {Aubl.) Huber 0/eiocai}JOII panamcnse (Pittier) Dwyer

frequent trees :

Bro!Vnea rnacrophyl/a Linden Cespedesia macrophylla Seem. Chome/ia spinosa J acq. Clusia spp.

198

D. M. PORTER

Cono.1·te~:ia xalt~peusis (llonpl.)

D. Don

flaistel'ialou~:ipes Standi.

M iconia borealis G Ieason Oumtea lucem (H.B.K.) Cngl. Pentagonia brachyotis (Standi.) Standi. P.macrophylla Bent h. Pogonopus >peciosus (Jacq.) Schum. Po.<Otfueria latifolia (Rudge} Roem. and Schult. Pourowna scobina R. Den. Sipt1rt111a pauciflora (Beurl.) A. DC. Stemmadenia gmudiflora (Jacq.) Miers Warszell'iczia cocciuea (Vahl) Klotzsch. Xylopia fmtesceus A ubi. locally dominant shrubs:

Cephaelise/ata Sw. frequent shrubs:

Til E VEGETATION OF I'ANAMA : A REVIEW

Miwnia oinuchruphylla Donn . Sm. Palicourea guiauensis Attbl. Picramnia dwyer! Porter (as 1'. antidesma Sw.) Piper durienense C. DC. P. marginatum Jacq. P. reticulatw11 L. Psyclwtriacapitata Ruiz and l'av. P. im•o/ucrata Sw. Quassia t/1//(/rtt L .

[Holdridge nnd Budowski (1956): as '·subtropical Wet Forest", Cerro Azul district beyond Loma l'clado, l'anam{l ]:

A/fiu·oa co.l'llll'icemi.\' Standi. J'odocarpus guatemalensis var. al/enii

[Lewis (197 1)', Cerro Azul, Panam{t]:

Stemmadeuia allenii Woodson

frequent banana-like or sma ll palm-like plants: Costm· mt/111/S K. Sch. Renea/mia cermw (Sw.) Macbr. Stromauthe lulea (Jacq.) Eichl. Xip!tidium caemleum A ubi.

[Lewis ( 1971), Cerro Jcfe, Pana ma]:

Byrsonima dres.\'leri Lewis Cephaelis rigidifo/ia Dwyer and H ayden Chione boxifo/ia Dwyer and Hayden Dukea ptmame11sis Dwyer Faromeajefensis Dwyer and Hayden Hampea micrant/w A. Robyns Lisianthus jefeusis Elias Polyga/aje[e11sis Lewis Psychotria gra11dic{IJpa Dwyer and Hayden

Drymonia spectabilis (H.B.K.) Mart. Passiflora l•itifo/ia H.B.K. frequent herbs:

P. olgae Dwyer ancl l-layclen Quarariben dolichopoda A. Robyns Riuorea dasyadena A. Robyns Rondeletia sa/icifo!ia Dwyer and Hayden Sclu-adera blumii Dwyer and Hayden Stelis/imbriata R. K. Baker Stemmadenia allenii Woodson Voch.1•sia jefensis A. Robyns

[Lewis ( 197 1), El Valle de Anton, Cocle]:

Coccocn;,·e/um herbac~um Lam. Spigelia anthe/mia L.

Cephaelis correae Dwyer and Hayden Hasseltia rigida A. Robyns Hibiscus cocleauus A. Robyns Hoj]ii/(IIIIJia capil/acea Dwyer

[Holdridge and Budowski ( 1956) : as "SubtropiCal M oist Forest", Chiriqui] : typified primarily by:

Quercus sp. (St<~ nd l.)

Ouchholzand Gray

frequent lianas:

Aphe/audra incamata Leonard A. sinc/airiana N ees Clm•ija mezii Pittier Faramea lute01•ireus Standi. F. occidenta/is (L.) Rich. Hurania pwpurea (Pittier) R. E. Schultes

199

Oumtea coc/eensis Dwyer Po/yga/a 11'1/Nittckiaua Lewis Souroubea vollicola de Roon Stemmadenia al/euii Woodson

Myrciaspp.

Eugenia spp.

[Lewis (1971), Santa Rita Ridge, Colon]:

Calderone/la sylmtica Soderstrom and D ecker Cordia dwyeri Nowicke

[Holdridge and Dudowski ( 1956): as "Subtropical Wet Forest", Chiriqui]:

Bmuel/ia cos/al'icensis Standi. Ca/ophyllnm bl'asi/ense var. l'ekoi Standi. Juga spp . Lap/aceafruticosa (Schrader) Kobuski La uraceac

Melastomataceae Ow·atea sp. Rubiaceae

C. porcata Nowicke

Elfin Forest

Temstroemia tepezapote Schlecht. and C hum. (as Taonabo seemannii (Tr. and Planch.) Standi .)

[Duke and l'orter (1970), Darien]: locally dominant trees:

frequent epiphytes:

Clusiaspp.

Cloud Forest

P>:J•clwtria pithecobia Standi.

[Duke and Porter (1 970), Darien]: locally dominant trees:

Oenocal'pus panamiinus Bailey

Miconia oinochrophylla Donn. Sm. Piper margiuatum Jacq. Psycho/ria valeriana Standi.

AcknoiVledgemcnts

frequen t trees:

Clusia spp. Heisteria longipes Standi. lrim·tea cometo (Karst.) Wend!. Ow·atea lucens (H.B.K.) Engl.

frequent banana-like or sma ll palm-like plants: Xiphidium caemleum A ubi.

frequent shrubs: Besleria pauciftora Rusby

Psychotria pithecobia Standi.

frequent epiphytes:

Various drafts of the text have been read by Dr. R. K. Baker, Dr. T. B. Croat, Dr. W. G. D'Arcy, Dr. J. A. Duke, Dr. J.D. Dwyer, and Dr. W. H. Lewis. Their many helpful criticisms are gratefully acknowledged. Not only has my wife Sarah read and improved the text, she also typed the manuscript and drew the maps that illustrate it. As alway~, her assistance has been extremely valuable to me.

[Ho ldridge and Budowski (1956): as "Lower M ontane Forest", Chiriqui]:

Cedre/a tonduzii C. DC. Persea schiedeana Nees

Quercus copeyensis Muller Weinmannia pinnata L.

'It should be noted that the species listed by Lewis are endemic to the Cloud Forest and may not be either locally dominant or even frequent.

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D. M. PORTER

T H E VEGETATION OF PANAMA: A REVIEW

Rct:c.renccs

Sapper, K., 1900. Miuelamcrikanische Reisen 1111d Studie11 au.1· den Jahm1 1888 his 1900. Friedrich Vicwig, Braunschweig, 426 pp. Sauer, C . 0., 1966. 711e Early Spanish Main. Univ. California Press, '13crkclcy/Los Angeles, Calif., 306 pp. Schery, R . W., 1942. A few facts concerning the nora of r,; nama. Chron. Bot., 7:77-79. Shelford, V. E., 1963. The Ecology of North America. Univ. Jllinois Press, Urbana, III., 610 pp. Smith, A. C. and Johnston, 1. M., 1945. A phytogeographic sketch of Latin America. In: F. Verdoorn (Editor), Planls and Plm11 Scien ce in L atin America. C hronicn Botanica, Walth am. Mass., pp. ll - 18. Standley, P. C., 1928. Flora of tire Panama Canal Zone. Con/rib. U.S. Nal. Herb., 27:1-416. Swan, L. C., 1966: The envi ronment of the Central American coldbloodcd vertebrate fauna. Copeia, 1966:684-699. Trcjos, E. W. and A rcher, A., 1953. Atlas Eswdistico de Costa Rica. M in. Econ. Hacienda Dir. Gen. Estadis, Censor, San J ose, 114 pp. T rewartha, G. T., 1961. The Earth's Problem Climates. Univ. Wisconsin Press, Mad ison, Wis., 334 pp. Viksne, A., Liston, T . and Sapp, C . D., 1970. SLR reconnaissance of Panama. Phologramm. Eng. , 36 :253-259. Wagner, P. L., 1964. Natural vegetation of Middle America. In: R. Wauchope and R. C. West (Editors), Handbook of Middle American Indians, /. Univ. Texas Press, Austin, Texas, pp. 216-264. Wiley, S.C., Dodd, A. V. and Cha mbers, J. V., 1955. Environmental Handbook of Fori Sherman and Fori Gulick, Panama Canal Zone. U.S. Army, Headq. Quartermaster Res. Dev. Comm., Environ. Protection Div., Tech. Rep., EP-17, Natick, Mass., 50 pp.

Bea rd , J . S., 1944. Climax vegetation in tropical America. Ecolog)•, 25:127-158. Beard, J. S., 1953. The savanna vegetation of northern tropical America. £col. Monogr., 23:149-215. Beard, J. S., 1955a. The classification of tropical American vegetation types. Ecology, 36:89- 100. Beard , J. S., 1955b. A note on g allery forests. Ecology, 36: 339- 340. Benne ll, C. F., Jr., 1963. A phytophysiognomic recon naissance of Barra Colorado Island, Canal Zone. Smiths. Misc. Coli., 145(7): 1- 8. Bennett, C. F., Jr., 1968. Human influences on the zoogeography of Panama. lbero-Americtma, 51: 1- 112. Bennett, H. 1-1., 1912. The agricullllral possibilities of the Canal Zone, I. Reconnaissance soil survey. U.S. Dept . Agr., Rep., 95:5-38. Benne tt, H . 1-1., 1929. Soil recon naissance of the Panama Canal Zone and contiguous territory. U.S. Dept. Agr., Tech. Bull., 94 :1 - 47. Duke, J. A. and Porter, D. M., 1970. Darien Phytosociological Diclionary. Battelle Memorial Institute, Columbus, Ohio, 70 pp. Erlanson, G. 0 ., 1946. The vegetation of San Jose Island, Republic of Panama. Smiths. ftilisc. Coli., 106(2):1-12. Garver, R. D., 1947. Republic of Panama Report. Office of Foreign Agr., Rei., Washington, D. C., M~ Goldman, E. A., 1920. Mammals of Panama . Smilhs. Misc . Coli., 69(5):1~309. Goldman, E. A. and Zetck, J., 1926. Panama. In: V. E. Shclford (Editor), Naltwalist's Guide to 1/te Americas. Williams and W ilkins, Baltimore, Md., pp.612- 622. Galley, F. B., McGinnis, J. T., Clements, R. G., Child, G. I. and Duevcr, M. J., 1969. The structure of tropical forests in Panama and Columbia. Bioscimfe, 19: 693- 696. Holdridge, L. R., 1957. The vegetation of mainland Middle America. Proc. Pac. Sci. Congr., 81/t, 4: 148- 161. Holdridge, L. R. and Budowski, G., 1956. Report of an ecological survey of the Republic of Panama. Caribb. For., 17:92- 110. Holdridge, L. R. and Budowski, G., 1959. M!!Jla eco/Ogico de Panamti: l nstituto lnteramericano Ciencias, Agricolas, Turrialba, Costa Rica. James, P. E., 1950. Latin America (revised edition). Odyssey Press, New York, N.Y., 848 pp. Johnston, T. M., 1949. The botany of San J ose Island (Gulf of Panama). Sargelllia, 8:1-306. Kenoyer, L. A., 1929. General and successional ecology of the lower tropical rain forest at Barra Colorado Island, Panama. Ecology, 10:201-222. Lamb, F. B., 1953. T he forests of Darien, Panama. Cm,ibb. For., 14:128- 135. Lauer, W., 1960. Probleme der Vegetationsgliederuhg auf der mittclamerikanischen Landbrucke. Tagungsber. Wiss. Ab!t., Disch. Geogr., Berlin, 1959:128. Lewis, W. H., 1971. High floristic endemism in low cloud forests of Panama. Biolropica, 3 : 78-80. Martini, J . A., A h Chu, R. and Nel Lezcano, P., 1960. Forest soils of Da rien Province, Panama. Trop. Woods,l12:28-39. Mayo· Melendez, E.,l965. Algunas caracteristicas ecol6gicas de los bosques inundables de Darien, Panama, con miras a su posible utilizaci6n. Turrialba, 15(4):336-347. Myers, C. W., 1969. The ecological geography of cloud forest in Pa nama. Am. Mus. No vitates, 2396: 1-52. Panama Canal Company, 1967. Climatological Data, Canal Zone aud Panama, Amwa/-1967, 59 ( 1). P anama Canal Company, Balboa Heights, Canal Zone, 49 pp. Park, 0., Barden, A. and Williams, E., 1940. Studies in nocturnal ecology, 9. Further analysis of activity of Panama rain forest animals. Ecology, 21:122-1 34. Platt, R. S., 1938. Items in the regional geography of Panama: with some comments on contem porary geographic method. Ann. Assoc. Am. Geogr., 28:28. Porter, D. M., 1970. The rape of Panama. Mo. Bol. Gard. Bull., 58(1):1 1- 17. Riitzler, K. and Steerer, W., 1970. Oil pollution: damage observed in tropical communities alon g the Atlantic seaboard of Panama. Bioscience, 20: 222-224.

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Chapter 7

Phytogeographic History of the Isthmus of Panama during the Past 12,000 Years (A History of Vegetation, Climate, and Sea-level Change) AL EXAND R A S. BARTLEIT Academy af Natural Sciences, Philadelphia, Pa. (U.S.A.)

and ELSO S. BARGHOORN Department of Biology, Harvard University, Cambridge, Mass. (U.S.A. )

Summary Palynological st udy of tropical lowland deep core sediments from the Gatun basin, Panama Canal Zone, has shown evidence of climatic and vegetational change d uring the period under study, from about 12,000 B.P. to the present. Although vegetational changes discernable in the pollen seq uences from these sed iments are caused chiefly by alteration of edaphic conditions owing to the infl uence of rising sea level, the effect of postglacial climatic amelioration is also evident. During the early part of this period, temperatures of at least 2.5â&#x20AC;˘c lower than those characterizing the Canal Zone today are indicated: This is shown by the presence of the pollen of pla nts not to be found growing in the Canal Zone today, which ini~abit higher altitudes elsewhere in Panama. By about 7,300 B.P., temperatures in the Canal Zone had risen to equal those of the present time. Pollen from the interval from about 7,300 B.P. to 4,200 B.P. suggests a drier, more seasonal, and perhaps cooler climate during thi~ period. Sediments deposited during the last several millennia contain pollen indicative of agriculture. Pollen from this interval has been identified as that of Zea; pollen of Manihot esculenta is also present. Zea pollen occurs also in a core sample which is between 6,200 and 7,300 years old; this early occurrence of Zea pollen is probably that of wild maize. The deep cores p10vide, in additio n, a chronology of rise in sea level from -11 ,300 B.P. to the present, showing a very rapid early postglacial rate of rise, and a pronounced slowing after about 7,300 B.P. Evidence suggests also the occurrence of an interstadial high sea level about 160ft. below that of the present about 35,500 years ago.

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Introduction

During the last se veral decades, much progress has been made in deciphering Pleistocene climatic changes, particularly of the last, or Wisconsin (Wtirm) stage. Evidence of these changes has, in good part, been derived from pollen analysis, which has provided abu ndant evidence concerning the scope and character of the vegetational cha nges resulting from these profound Pleistocene cl imatic fluctuations. Pollen studies and their statist1cal treatme.nt have served as a method fo r determining Pleistocene vegetational and climatic fluctua ti ons since their development by Lcnnart von Post ( 19 16) under the guidance of Lagerheim in the second decade of the 20t h century (Faegri and Iversen, 1964). Von Post's classic palynological st'udies of Scandinavian sediments were carried out in co nj unction with varve analysis, which provided the necessary chronological framework. . Extension of pollen analysis to non-varved sediments in Europe and North America has since provided abu ndant and detailed evidence of vegetational change in both continents. Geochronological interpretations of these vege~ati onal changes could not be successfully atte mpted, however, unt il the early 1950's, when development of radiocarbon dating provided a means for determining the absolute age of pollenbea ring sediments. Subsequent work has tes ulted in the development of a chronology of vegetational and climatic change during the past 10,000-12,000 years in Scandinavia, Europe, and the United States. Th is ch ronology, which shows essentially parallel climatic changes on both sides of the Atlantic basin, has gradually been extended to include full-glacial portions of the Wisconsin, older than 12,000 years, and to earlier portions of the Quaternary. Evidence of climatic and vegetational changes of the Pleistocene has been generally confined, until qu ite recently, to temperate and north-temperate zones. 8lthough low latit udes have often been considered as ideal fo r determining world-wide effects of Pleistocene climatic changes, little progress has been made in pollen analysis of lowlatitude sediments until the past decade. Consequently, little had been learned of the effects of Pleistocene climatic influence on low-latitude vegetation. Northern S outh America

Several noteworthy palynological investigations of Pleistocene and Recent sed iments have recently been c~nd ucted in northern South America by T. van der Hammen and his co-workers. Preliminary results of a palynological study oflake sediments from the Sabana de Bogota in Colombia were reported by Maarleveld and Vander Hammen (1959) and were subsequently discussed in detail in Vander Hammen and Gonzales {!960a). This very interesting detailed study dealt with fossil pollen from lake-deposited sediments of the Bogota plain, situated at an altitude of ca. 2,600 m above sea level and4.5째-5째 North latitude.

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205

St udies of" the modern vegetation of this area showed that the altitude of the tree line in the mountai ns surrounding the Bogota plai n was a functio n ~f both moisture and temperature. Thus, greater and more continuous precipitation wer; found to resul t in a higher "tree line. Abundance of oak was found to be an excellent indicator of humidity, while Gramineae and Acaena were plants characteristic of the open "paramo" vegetation occurring above the tree line. Vander Ham men and Gonzales determined by a study of modern pollen rain in the area that the abundance of oak pollen in contrast to that of Weinmannia and other forest elements could p rovide an indication of relative humidity or aridity, while the vertical distance to the tree line from the Bogota plain could be determined by the rela tive amount s of pollen of Gramineae and Acaena reaching the Bogota sedi ments. Fluctuations in time of fossil polle n percentages of these two groups allowed, therefore, the elaborati on of curves showing: (/) the past altitudinal displacements of the tree line; and (2) fl uctuations in rainfall. Using these data and the fact that the altitudinal temperature lapse rate in the mountains surrounding Bogota is 2/3째C per 100m, Vander Hammen and Gonzales were able to postulate fluctuations of the tree line due to temperature changes alone, and were thus able to construct an absolute tem perature curve showing inferred temperature fluctuations at the Sabana de Bogota during Pleistocene and Recent t ime~As a result of this study, these authors reached a number of interesting generalizations regarding probable Pleistocene climatic changes in the low latitude tropics. These may be summarized as follows (Vander Hammen and Gonzales, 1960a). (I) Northern tem perate regions and the tropics are thought to have been equally affected by Pleistocene climates. The tropics, like temperate regions, had both glacial (cold) and interglacial (warmet) climatic episodes. (2) Average yearly temperatures in the upper Andes at the height of the last (Wisconsin or Wli rm) glaciation are inferred to have been ca. 8째C lower than today's. T hese temperatures, the authors point out, are comparable to those calculated fo r the European Pleistocene. (3) Glacial periods in the Andes are considered to have been times of increased precipitation (pluvials) while the interglacials were periods of lowered precipitation (i11terpluvials). (4) Both major (glacial and interglacial) and minor climatic fl uctuations of Pleistocene and Recent time in equatorial South America are considered to have been contemporaneous with parallel changes in temperate regions. (5) Eight late-glacial and postglacial zones, apparently corresponding very well with those recognized in Europe, are distinguished in the Sabana de Bogota pollen diagrams. Van der Hammen and Gonzales (1 960b) and Van der Hammen (1961), in a subsequent palynological study of the history of the Paramo de Palacio near Bogota, confirmed conclusions reached in the study of the Bogota Sabana. In this study, eight

206

A. S. IJARTL ETT AND E. S. lJARGHOO RN

late-glacial and postglacial pollen zones were also distinguished, all of which were considered to be perfectly synch ronous with European phases. The "hypsither mal interval" is also recognized, and is calculated to have been from 2 to 3°C warmer than al p resen t, as shown by tree-line fiuctuat i on~. The latter d ed uction is a debatable conclusion . An add itional recent paper by Gonzales et al. (1966) deals with climatic changes as indicated by both the pollen re~ord and by glacial drift in the Sierra Nevada del Cocuy in Colombia. C li matic interpretat ions of these glacial drift and pollen sequences a lso agree very well wit h those of northern Europe, although the interpretations of portions of the pollen record are more uncertain in this case than in the other Colombian studies. This is d ue to low absolute pollen frequency, and to the fact that back: ground pollen rai·n from trees at lowe1 altitudes may obscure the indigenous pollen rain prod uced by the very sparse high altitude vegetation. The a uthors were puzzled by the circumstan ce that the climatic cooling of the seemingly well-docum ented North American Coch rane glaciation which took place about 8,000 years ago is not reflected in the pollen record of either Colombia or northern Europe.· Palynolog ical study of lowland sediments of equatorial S_outh America has also been initiated. One study (Van der Hammen, 1961 ; 1963) of coastal sediments near Geo rgetown, British Guiana (5-7°N latitude) shows that the vegetation dufing the Wisconsin (Wiirm) included mangrove swamps, with brackish to fresh water swamps and marshes directly shoreward. The extensive plains inland, according to Van der Hammen, may have been covered by g rass savannas with a depau perate flo ra in terms of species. Late-glacial and postglacia l deposits were deposited on the shelf under the influence o f rising sea level. No climatic interpretations are drawn from· the pollen record of this period, during which mangrove (Rhizophora) vegetation was dominant. Another recent study by Wijmstra and Vander Hammen (1966) deals with the history of tropical savannas in northern South America. Palynological investigati ons of cores from sites in both Colombia and British Guiana have shown that savannas have existed in both regions for the past several millennia, and that this vegetation was preceded by a dry forest or closed savanna woodland. In Colombia, cores from the Agua Sucia region of the Llanos Orientales showed that open savannas had developed by about 3,000 B.P. The authors considered, however, that an earlier period of open savannas in this region, from ca. 5,000 to 4,000 B.P. may have existed. In the Rupur uni savannas of British G uiana, proportion s of savanna woodland and open savannas changed repeatedly from about 9,000 to 10,000 B.P. to about 5,000 B.P. From 5,000 B.P. to the p resent , open savanna dominated the area; Wijmstra and Vander Hammen are of the opinion that human influence during the past three millennia may have been an important factor in the extension of these savannas.

Southern Central America Preliminar y study of montane bog sections from an elevation of about 2,400 m in the

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207

Talamanca Range of Costa Rica was conducted by Mart in (1960). T he study indicated that open paramo vegetation characteristic of colder climate existed there at least 600- 800 m below its prese nt altit udinal l imit, at some time in the past. No definite conclusions were reached, however, as rad ioca rbon dates were not yet available at the time of publication of this stud y. A .palynolog ica l study of sediments from Lake Petenxil, Guatemala was conducted by Tsukada ( 1966). Although these sedi ments provided evidence of agriculture , no climatic interpretat ions were drawn. Tsukada concluded from his study that, in Guatemala , man was responsible for developme nt o f forest vegetation from regions formerly occupied by grasslands . This, of course, is the reverse of the situation though t to exist in other parts of the world. Panama

A very fortunate oppo rtunity to learn more of Pleistocene climatic effects in tropical Central America was provided when the second author learned of the existence and availability of deep cores from the Gatun basin in the Panama Canal Zone. D uring the period from late December 1961 to early January 1962, he had begun a project involving the sampling of bottom sediments of Gat un Lake with the intention of comparing the pollen and spore 1 ssemblages recoverabl e from t he sediments with their native vegetation source in the bordering rainforest. Gatun Lake had been chosen forth is study because of the completeness o f its historical record as a man-made artificial lake, and also because detailed infot mation abo ut the flora and vegetation was available. I n the course of this work he learned of the existence of large numbers of cores, which were generously made available for sampling by Robert H. Stewart, Geologist of the Panama Canal Company, and other officials of the Engineerin g Division. The cores, drilled by the Panama Canal Company in sediments of the Gatun basin in preliminar y inve;;tigations as p reparation for constructio n of a new dam across an arm of Gatun Lake, extend through several hundred feet of sediments deposited in the Gatun basin under the influence of the postglacial rise in sea level over the underlying and complex Tertiary sedimentary sequence of rocks. Upon examination of the cores, it became evident that an unparalleled ·opportunity was at hand for study not only of the recent, post-lake sedimentat ion in the Gatun structural basin but also of its late Pleistocene vegetational and climatic history. Additiona l field work was carried out in the winter of 1962-63, and samples were selected from eight of the cores considered most suitable for pollen analysis. This study details the results of our palynological investigations, radiocarbo n age data, interpretat ion of sea level, climatic and vegetation al change and other facts of scientific informatio n gleaned from the cores and lake bottom sediments.

208

A. S. UA RT L ETI AN D E. S. BA RGH OORN G~logical

history of Panama

Pre-Quaternary history The lsthmus o r Panama has had a highly co mplex geological history, the details of which are of g reat i n tere~t. pa rticula rly because of its function as a link between t he continents of North and South America. T his involved history has proven diffic ult to unravel, as rock o utcrops are scarce owing to deep tropical weatheri ng, fossil fi nds are relatively few, a nd field cond itions are d ifficu lt, pa rtially because of the dense cover of tropical vegeta tion. General agreement has no t been reached except about the very broad o utlines or Pa nama's history. Recent opinions about the co urse of geological events in the Canal Zone do concur, however, in postulating that the region was characterized th roughou t the T ertia.ry by shift ing groups of islands and peninsulas a ttached, in t urn, to one continen t or the other ( Lloyd, 1963; Whitmore and Stewart, 1965). f n his discussion o f the geologic history o r south Central-America, Lloyd ( 1963) has d ivided the area under considerat ion into three portions, To the north is N uclear Central America, which is defined by Vinson and Brineman (1963, p.I OI) as "comprising the eastern portion of the Sierra Mad re del Sur, its ancient geanticline and the flanking geosynclinal po rtio n of the Gu lf Coast 1lnd the Carribean embayments. Southeastern Mexico, Guatemala, British Honduras, Hondu ras, and Nicaragua make up the p rincipal land area". So uth of this land area is a region named the "South Central-A merican orogen" by Dengo (1962), which is defi ned, accord ing to Lloyd ( 1963, p.88) as "a geologic unit sharing a common history, (which) includes a part of the Republ ic o f Panama, all of Costa Rica, and that portion o f Nicaragua south of latitude I3Â°30' N" . Lloyd designates t he southernmost portion of the regio n considered by him, as the "Panama spur". This comprises eastern Panama from Gat un Lake to t he Colo mbian border. Lloyd considered its geological affinities to be with the South A merican continent rather than with t he south Central-American orogen. The waterway which traversed the south Central-American o rogen d uring much of the Upper Jurassic, C retaceous, and Tertiary is referred to by Lloyd as the mid-American Channel. The decipherable geological histo ry of Panama began, accord ing to Lloyd, at t he end of Middle J urassic or in Late J urassic time, with the folding of the mid-American Channel into a series of ridges striking southeast to northwest . Thro ugho ut the Tertiary, these eastward -progressing orogenies occurred successively, resulting in extr usion of lava and the formation of volcanic cones; some of these attained large dimensio ns, forming islands. During the mid-Oligocene the last fold , called the Talamanca Ridge, rose. Composed of islands at first, t he entire Talamanca Range had emerged by the Midd le Miocene. The Pacific slo pe of the o rogen was elevated by Pliocene movemen ts, thus forming an isthmian link between Nuclear America on the north, and the Panama spur and hence South America to the south. Conclusions abo ut Panama' s early geologic history drawn by Whitmore a nd

PHYTOGEOG RA PH IC I-I ISTOR Y 01Â° T HE ISTH MUS OF PANA M A

209

S~ewart (1965) d ificr sig.nificantly from Lloyd 's in several respects. The former, who d1d. not atten~pt to descnbe Panama's p rc-Terliary and Tertiary history in detail, drew the1r conclusions on t he basis of a recently discovered mammal fauna from the Canal Zone . . Mammal bones fo und in t he Miocene Cucaracha Formation are all, according to Wlu tmorc and Stewart, th ose of browsin g un gulates and represent a herbi vo rous fau na whose range extended during the Miocene o ver much of what is now the U nited States. Of the five identifia ble mammal genera in the Cucaracha Formation, four (Diceratlr.eriw~1, Ancltitlrerium, Arclraeolrippus and Merycochoerus) were recognized as congcnenc w1th North A merica n fo rms, the fifth belo nging to a North Am erican family (the Protoce ratidae). T he presence of und ifferentiated members of this N orth American fau na in the M iocene of Panama was considered by Whitmore and Stewart as evidence that the isthm ian region was p roba bly a ttached to North America continuous(~ during the Tertiary by a large a nd stable la nd mass. T he tectonically active Isthmus Itself, on the o ther hand, was probably an arch ipelago during most of the Tertiar y. Marine deposits stratigraphica lly beneath and above the Cucaracha d eposit indicate that marine transgression had taken place both before and after the anival of the Canal Z one mammals; Whitmore and S tewart postulate, therefore, tha t the ~resent Canal Zone a rea was probably the site of a nar row seaway, which was uplifted and thus closed several ti mes during the Tertiary. The Panama sp ur was viewed by Lloyd a s a relat ively stable la nd mass connected throughout the Tertiary with the South America n co ntinent. Whitmore and Stewart o n the other hand, give evidence that the spur, which they prefer to designate the "Sa~ Bias Area", was an island which was separated from So uth America during m ost of the.Te: tiary by a maj or seaway, the Bolivar Trough. T hb area may have been j o ined penodically to the stable Talamanca Range to the west, before it became connected to South America by the closing of the Bolivar Trough in the Late Tertiary. After completion of the isthmian link in Late Tertiary time, additional Jess sweeping tectonic adjustments took place; by the Late Quaternary, the south CentralA merican orogen had achieved its presen t sha pe, and volcan ic activity in Pa nama had ceased (Lloyd, 1963).

Late Quaternary and Recent history T he isthmian portion o f Central America is characterized by a considerable am ount of tectonic activity to t he p resent day (Whitmore and S tewart, 1965). There is, however, no convincing evidence to indicate instability of the Canal Zone du ring Late Pleistocene or R ecen t time. Early accotmts of profound instability of the isthmus during this period resulted from misinterp retation of the geologic evidence due to failure to consider eustatic sea-level change. T his led to some rather peculiar interp retations of Panama's tectonic history; a n o utstanding rather interesti ng example is MacDonald's version (1 913, p. 573) :

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A. S. BARTL ETT AND E. S. BARG HOORN

"Toward the middle oftiTe Pleistocene the land rose until it attained an allitude of more than 400 fl. above its present elevat ion. This is known to a certainty because the old Pleistocene channel of the Chagres River, at Gatun, is about 375 fl. below present sea level, and such a depth could not have been excava ted by the river except under conditi ons where the land ~tood much higher than now. After Midd le Pleistocene time a gradua l submergence began. This went on until the laqd in the vicinity of Colon stood about 8ft. lower than now. Tn the vicinity of Aguadulce this period of s ubmergence carried the land 25 ft. below its present elevatio n. As it sa nk, the sea invaded the lower ends of the valleys and these became gradua lly silted up by stream sediments. On these shallow si lted areas swamp vegetat ion flourished . Silting and vegetable growth kept pace with the sinking and thus were formed the swamp areas along the ~eacoas t, near the mouths and in the lower parts of stream s." MacDonald postulated that the most recent land movement fo llowing the 25-ft. submergence was an emergence of equiva lent magnitude. This inference was appare ntly based solely on a kitchen midden shell mound, located about 7 miles southwest of Aguad ulcc, and about 25' above present sea level. In view of the character of this deposit (and also the fact that, according to Terry, 1956, it is. located in a fault zone near an earthquake epicenter) it does not seem j ustifiable to accept it as evidence of recent land emergence. Panama Pleistocene marine deposits now abov~ sea level are found, accordi ng to the literat ure, in only two locations. T he first, on the Burica peninsu la ncar Puerto Armuelles, consist s of foss ili ferous soft clays with layers of sand, and has a thickne ss apparently exceed ing 600 ft. The base of this formal ion is elevated inland by as much as 100ft. or more (Terry, 1956). This occurrence is a clear-c ut case of local instability; this deposit is located in the vicinity of the most import ant fault in Chiriqui Provin ce, which passes through P uerto Armuellcs. Intersection of this and other N45â&#x20AC;˘E-striking fau lts with those striking NW-S E divide the area into a numbe r of presently unstable fault blocks (Terry, 1956). The other Pleisto ce ne marine deposits, which Woodr ing (1957) though t were probably of Late Pleistocene age, are loc~tcd near the norther n portion of Gatun Lake, one at the lower end of the Gat un Locks, and the other in the Black Swamp near Mount Hope (BrtJwn and Pilsbry, 19 12). The deposit at the north end of the Gatun Locks, which extends from a few feet below sea level to about 10 ft. above, contains chiefly oy.ster shells which were though t by Brown and Pilsbry to have grown on mangroves, judging by the impression on their shells. They were of the opinion, therefore, that this was a deposit accumulated at the head of a bay or in an estuary, but Woodring (1 957) though t that the matrix pointed to deposit ion in a swamp . The Mt. Hope deposit, which was correlated by Brown and Pilsbry with similar deposits beneath Colon, lies about 4 ft. above present sea level and contains corals, coralline fragments, numero us oyster !>hells and other mollus cs. Woodring considered that the depositional environment of this deposit was uncerta in on the basis of the published data.

PHYTO GEOG RAPHIC HISTO RY OF TH E ISTHM US OF PANAM A

211

Uplift of abotll 25-30 ft. has also been postulated more recently by Jones (1950). Jones, however, cites no evidence to substan tiate this hypothesis; one suspects strongly that he relied on MacDonald's ( 19 13) evidence. In the absence of incontrove rtible evidence to the contrar y, thcrcl'o re, it seems likely that the Canal Zone area has been essent ially stable during late-glacia l and postglacial lime. Late-glacial and postglacial sedimenta ry deposi ts are widesp read in lowland deposits of the Canal Zone. In the Gat un basi n, these deposi ts extend to more than 160' below sea level and occ ur up to allitud es a few fee t above sea level, as shown by cores dnlled by the Panama Canal Com pany. T hese sedime ntary marine, swam p, and flu vial deposits, deposited under the inn ucnce of the postgla cial ris ing sea level, were collecti vely termed the "Atlantic Muck" by Canal Zone geolog ists, and were described in detail by T hompson ( 1947). Their late ral extent ha~ been mapped and is shown by Jones ( 1950) on his geo logical map of the Gat un Lake area.

Physiography and climate of PanamaThe Republic of Panama, a sigmoid-shaped east- west trend ing strip of land, has a total area of about 29,000 sq. miles. Its maxim um extensi on is about 390 miles, and its maximum north- sou th ex,tension is about 170 miles. At its narrowest part, the Canal Zone, it is only about 45 miles wide. Hills and mounta ins of the continental divide, which runs the length of the Republic, are lowest in the Canal Zone, where they reach a max im um altit ude of only 300 m. The Cordill eran Mount ai ns rise gradually cast and west of the Canal Zone, reaching alt itudes of over 3,000 m in Chiriqui Provin ce to the west, and more than 2,000 m to the cast in Darien Province. The highest point in the Repub lic is in Chiriq ui Province ; El Baru, commonly known as the Yolcan de Chiriqui, reache s a heighto f 3,480 m. The largest lake in Panama, Gatun Lake, is located in the Canal Zone. This artificial la ke, the drilling ;;i te of the cores used in the presen t study, has an area of about 164 sq. miles; its surface is about 85 ft. above mean sea level (Kenoyer, J929). Until the time of the fl ooding of Gatun basin to a maxim um depth of 90 ft. by the damming of the Chagres River in 1914, the lowlands of the Gatun basin were covered with extensive swamps, which grew on poorly-drained sedime nts with an altit ude of less than 25 ft. above mean sea level. At the time of flood ing, numer ous hills of the area were converted to islands, the largest of which, Barro Colorado Island , has an area of 5.71 sq. miles (M cCullo ugh, 1956). Climate of the Canal Zone

The humid- tropical climate of the Canal Zone differs strikin gly on the northern and southern sides of the continental divide. The drier Pacific slope receives about 70 inches of rainfall per year, while the moist Atlant ic slope receive s abo ut 130 inches, or

A. S . BARTLETI AND E. S. BARG II OORN

PHYTOGEOG RAPH IC HtSTOR Y OF TH E ISTHMUS OF PANAMA

nearly twice as much. T he Pacific-slope has a pronounced seasonal distribu tion of rainfall, with a dry period from the end of December to early April. During the driest months, February and March, there arc on an average only two or three rainy days per month. At Cristobal o n the Atlantic coast, on the other hand, there arc an average of 12-14 rainy days during the driest months of February and Ma rch (M cCullough , 1956). Thus, while there is a recognizable d ivision into a wet and a dry season on the Atlantic slope also, it is not nearly as pronounced as that on the Pacific coast, only 45 miles away. This climatic diiTerence is reflected by the vegetation of the two slopes. That of the Pacific slope, following Standley {1928, p. 9), presents a dreary picture toward the end of the dry season: "Many of the trees ha ve lost their leaves, and even those still clothed have drooping withered foliage wh ich rustles and rattles in the breeze. Many of the bushes are bare, and the herbaceous plants are as brittle as if dried in a kiln, crumpling into dust as one walks over them. Upon the savannas no pasture is left fo r the cattle. At this season grass and brush fires are of daily occurrence, devo uri ng the parched plants..as if they were tinder, and leaving a waste of black in their wake." . Such a change in the vegetation does not occur on the Atlantic slope, however, except under unusual circumstances. Here, accord ing to Standley, the vegetation remains green: throughout the year, very few of the trees sheddi ng their leaves (with the notable exception of the Bombacaceae, which shed their leaves no matter how

divide separate the flora into two basic clements which reflect the climate di fferences ~etween thc.two slopes. On the Atl<.tntic wa.tcr.shed, dense fores ts prevail. This vegetallon, accord1ng to Stand ley ( 1928), 1s very snmlar to that of the whole eastern coast of Central America as far north as Guatemala. This vegetation, unlike that of the Pacific coast, includes no savannas. Vegetation of the Pacific coast also has great affinity with that of Costa Rica, El Salvador, and Guatemala to the north. Forests are less dense than those of the Atlantic coast, and savannas· occur on the drier slopes. A detailed account of the sim ilarities and diiTerences between the vegetation of these two regions is given by Standley in his interesting and informative general description of the vegetation of the Ca nal Zone. · Apart from the basic division of the vegetation into that of the Atlantic and Pacific slopes, Schery (1942) has divided Panama into six intcrgracl ing floristic regions, which owe their difrerences mainly to effects of di.fTering altitudes and edaphic conditions. These are (not in order of importance): {1) savannas; (2) highlands; (3) sub-alpine regions of volcanic peaks; (4) coastal beaches and swa mps; (5) inland pond, ri ver and lake areas; and (6) lowlands. Vegetation of the savannas is characte rized by an abu ndance of grasses and sedges, and by plants such as Polygala, Borreria, Ruellia, La!llana, He/icteres, and many small legumes (Schery, 1942). Vegetation of the highlands which are found in the interior of Panama at elevations from about 900- 2500 m incl udes, acco rding to Schery, such plants as Smilax, Piper, Peperomia, Solanum, Rubus, Mah•m·iscus, Begonia, Ipomoea, Sida, Passijlora, Erythrina, many ferns, Bromeliaceae, Araceae, Urticaceae, oaks, Melastomataceae, and Rubiaceae. Temperatures here vary from about 5° to 20,C, and abundant moisture is provided by mists and frequent light rains. The sub-alpine regions above 800 m are characterized by Schery as cold, windy, and usually mist-enshrouded. Plants characteristic of this -region are exemplified by those on the Volcan de Chiriqui, which include Bamboo, Weinmannia, Sisyrinchium , Hypericum, Alchemil/a, Valeriano, and many Ericaceous shrubs. Vegetation of the last three types grows abundantly in the Canal Zone, and is represented by fossil pollen in the Gatun basin sediments. Coastal mangrove swamps characterized by Rhizophora, A l'icennia, Laguncularia, and Conocarpus are widespread along the shores. Along sandy beaches exposed to the surf grows vegetation of the second type, characterized by beach plants such as Ipomoea pes-caprae, Canm•alia 1110/!tima, Hymenocal/is americana, Croton puncta/us, Cvccoloba uvifera, Caesalpinia crista, and Dalbergia ecastophyllum. Vegetation of inland ponds and lakes is characterized by aquatics and semiaquatics such as Sagittaria, Jussiaea, Polygonum, Pontederia, Eichhornia, Pistia, Castalia, Cabomba, Salvinia, and Utricularia, which abound in part of Gatun Lake (Standley, 1928; Schery, 1942). Lowland forests may be divided into two types: those growing in swamps in

212

wet the climate). Seasonal variations exist also in wind directions and velocities. Prevailing winds during the dry season are northwest to north at Balboa Heights, and north to northwest at Madden Dam. At Cristobal on the Atlantic coast, on the other hand, winds during the dry season are north to northeast (the northeast trade winds) (M cCullough, 1956). D uring the remainder of the year, prevailing winds are northwest to north at Balboa Heights, and variable at Madden Dam and Cristobal, with no pronounced prevailing direction. Monthly mean air temperatures vary little throughout the year, and the yearly average of monthly mean temperatures at Cristobal, which is 81°F, is representative of that of the entire zone. Extreme temperatures at Colon during 56 years of record were .66° and 95°F (Kenoyer, 1929). With rare exceptions, however, the temperature varies between 70° and 90°F. The mean daily temperature is practically constant from month to month. The monthly fluctuation at Gatun, fo r example, is about 1.4° (Kenoyer, 1929).

The present vegetation of Panama Panama may be divided into a number of floristic region~. corresponding to latitudinal and altitudinal differences in climate. The hills and mountains of the continental

213

214

A. S. BA RTLETT AND E. S. BARG HOORN

l'H YTOGEOGRA PHIC 1-IISTORY OF THE IST HMUS OF PANAMA

poorly-drained areas, and those-of the well-drained higher grou nd. T he Iii st is exemplilied, according to Standley, by the dee p, densely forested area5 in the vicinity of Fort Randolph and Fort Sherman. What remai ns of this vegetation, unlike that of most of the rest of the Canal Zone, has been little altered by man. In these swamps grow plants StiCh as Prioria copaifera, which is ortcn very abundant and may grow in nearly pure stands, called "cativos". Also occurring in these poorly-drained areas are many coarse monocots such as Heliconia, Marantaceae, and many Rubiaceae (Standley, 1928). In addition, there may be scattered individuals of Pterocarpus officina/is, Symphonia globulifera, Carapa slateri, and Malpighia g/abra, to name a few of the species occupying such habitat s. The mar~ h fern, Acrostic/wm danaeifolium, fo rms dense sta nd s at the brackish-fresh water boundary, and Rap!tia palm may grow abu ndantly, sometimes domin ating large areas (J oh nston, 1956). Better-drained lowland forests are exemplified by those on Sarro Colorado fs land, on which grow also representatives of most of the other important groups represented on the At lantic slope. Sarro Colorado Island is an ideal setting for the study of tropical rainforest vegetation (and anima l life as well), as it harbors a great d!versity of plant forms, provid ing examples of mature forest, secondary forest, seasonally inundated type~, and aquat ic and marsh vegetation. In addition, it is the site of a tropical research labo ratory. The island, which was designated ~s a permanent biological reserve by the Governor of the Canal Zone in 1923, remains unspoiled largely through the ei'T'orts of the late T homas Barbour and James Zelek, who were instrumental in having the island declared a natural preserve. The island, now called the "Canal Zone Biological Area", has been administered-by the Smi thsonian Insti tution ~ in ce 1946. The southern half of Barro Colorado Island was thought by Kenoyer ( 1929) to be primeval forest. He cited Standley's (1927) opinion, however, which pointed out that it was difficu lt to prove that any area in a region wh ich has been an important trade route for over 400 years has not been cleared and cu lti vated at some time. Whether or not this is virgin growth, it is very interesting as a forest which has remained undisturbed for many years, and has provided an excellent site for obtaini ng surface sed iments for the study of the modern pollen rain of a comparatively natural vegetation. ·Although it is difficu lt to single out the dominant species of this vegetation, as the most common species may differ from site to site, Kenoyer (1929, p. 207) has compiled a tentative li st of mature forest species as follows: Socratea durissima, Ficus

stra ngling r-igs as well as Dendropauax arboreus, Symphorria globulifera, and C/usia sp. The vascular epiphytes comprise, according to Kenoyer, more than 10% of the Barro Colorado plants, and belong to a num ber of gro ups, notable among which are the ferns, Araccae, the Orchidaceae, Bromcliaccae, and Piperaceae (Peperomia). Undergrowth in this forest is sparse, appa rently limited drastically by inadequate light. Among the plants managing to survive in this dimly-lit environment arc P:,ychotria and Se!aginel!a, ~swell as other Rubiaceae and various monocots. The fo rest on· the northern half of the island is second-growth vegetation. Kenoyer gives an account of the reforestation of this formerlY. cleared land, enumerating characteristic species of each stage; a brief review follows. First to invade newly-cleared ground are grasses and sedges, ·as well as weedy plants includi ng members of the Amaranthaceae, Compositae, Phytolaccaceae, Euphorbiaccae, and Solanaceae. Among the trees prominent in the next stage are Trema, Cecropia, L uehea seemannii, Apeiba, Heliocarpus, Oclrroma, Didymopanax, and Cordia, especially C. a!liodora. Outstanding among these is C ecrrJpia, a very rapidly growing tree which becomes very abundant. Almost as rapid ly growing is Ochroma, the balsa tree. During this phase, Miconia argentea of the Melastomataceae is also frequent. Undergrowth during th is phase may be quite dense. Many of these species are also those act ing as pioneers in cleared areas of the rest of the Zone. Johnston (1956) and Standley ( 1928) list a number of these plants, among wh ich are: Piper auriltllll Cecropia mexicana

Cecropia longipas Trama micrantlw Phyllanthus brasiliensi;· Spondia.1· mombin Luehea seammmii Apeiba tibourbou Ocltroma

g/abrata, Virola panamensis, Prioria copaifera, Dipteryx panamensis, Platypodium maxonianum, Zanthoxylum panamense, Hura crepitans, Spondias mombin, Bombacopsis fend/eri, Sterculia apetala, Symphonia globulifera, Crias fend!eri, Terminalia hayesii, Jacaranda copaia, Tabebuia pentaphylfa, and Tabebuia guayacan.

Vegetation on the island abounds with lianas, hemi-epiphytes, and epiphytes so characteristic of tropical rainforest vegetation. Thirty four fam ilies are represented here by lianas according to Kenoyer (1929). Representative hemiepiphytes are the

215

I !:

Haliconilt Visnuii lar({olia Ca/arhea Adetwria Setjania Triumfotla Neliclare.\· guazumaafolia Guazuma ulmi/olia Conostegia xalapensis

T he trees, according to Johnston, behave like "arborescent weeds", growing very rapidly. Their seeds germinate only in open sunny places, never germinating in shady places such as inside mature forests. There is, therefore, only one generation of weed trees in the regeneratio n of a fo rest from cleared areas. Seeds of trees characteristic of the permanent forest will, however, germinate in such environments. _ Many of the pioneer species persist in the more mature pioneer forest. To these are added many other species as the fo rest grows older. The number of species, according to Kenoyer, may reach its maximum in the mature pioneer forest from fifteen to fifty years a fter clearing. The number of species may decline later, as the permanent vegetation takes over. Altho ugh it is difficult, according to Kenoyer, to single out characteristic species in the old pioneer fo rest, owing to the large number of species present, he gives a few examples such as Ficus, 0/media aspera, Castilla

A. S. BARTLETT AND E. S. HARGHOORN

216

PIIYTOGEOGRAPHIC H ISTORY OFTBEJSTHMUS OF PANAMA

217

panamensis, Coccoloba, many species of Juga, Zanthoxylum, Protium, Sapium, Gusta t'ia, and many small tree or sh ru b Melastomes. Thi s pioneer vegetatio n finally gives way to the mature forest exemplified by that on the southern half of the island described earlier.

Preparation of samples At the beginning of this investigation, it was thought probable that the pollen content of the different cores from the Gatun basin wo uld be sufficiently similar to ·permit elaboration of a single diagram, using the best pollen sample available at any given

1 J '

I oo~-

so•

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10 I

Miles Fig.!. Panama, Gatun Lake area.

Fig.2. This map, showing the portion of the Gatun basin under study, represents the area as it was prior to the formation of Gatun Lake by flooding of the basin. The outlined land areas represent ground above the 100-ft. contour.

stratigraphic level. Therefore, the most promising portions of each of eight cores were sampled , at l-ft. intervals. The portions of each core to be studied were removed from the core boxes in the warehouse in Panama in which they had been stored, and placed in individual plastic bags which were then wrapp~d in aluminum foil. Moisture-containing samples were stored in a 0°F freezer. The Gatun Lake area, in which the cores were drilled, is shown in Fig. I. The geographical location of each core as determined from P anama Canal Company drill logs is mapped on Fig.2. The number of each sample used in the study is given to the right of each p ollen diagram at the appropriate depth. Eighteen samples were radiocarbon-dated ; these are listed in Table I. Also shown in Fig.2 are samples secured from sediments currently being deposited around Barra Colorado Island; these are designated 26-1, 26-2, 24-2, and 21-1. These samples, collected during December and January of 1962-1963 and 1963- 1964, were obtained with a piston sampler with plastic coring tubes for the purpose of determining the relationship of the present pollen rain to vegetation now growing on the island.

2 18

A. S. l3ARTLETI AND E. S. llARGHOO RN

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Preparation techniques

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219

PHYTOGEOG RAPHIC HISTORY OF TH E ISTHMUS OF PANAMA

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Sample preparations were made accordi ng to techniques developed in the second author's laboratory for treatment of h ighly inorganic, clayey sediments. Acetolysis was carried out according to the formula presented by Erdtman (1 934). Preservation of sampies

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Examination oft he prepared pollen samples showed a wide range of state of preservation of I he pollen, from excellent to poor. Most of the samples contained excellently preserved pollen while pollen in olhers showed clea r evidence of fungal or bacterial attack. One typical fo rm of a!lack is pictured in Plate Xl ll, 10; the circular corr oded areas on this fern spore, consisting of cl osely spaced narrow channels radial ing from a point and all terminating at roughly the same d istance from it, are sometimes linked by a single groove, and freq uently overlap in badly corroded grains. Very similar patterns have been described by Elsik (1966), who attributed them to fu ngal act ivity. Many of our samples showed evidence of intensive fungal activity; much of the mangrove muck abounded in fu ngal spores and hyphae. The state of preservation of the pollen in the samples, however, showed no relationship to the amount of fungal activity present. Indeed, several of th~ samples with the most abundant fungal spores and hyphae contained beautifully preserved pollen. An unusual form of degradalion was observed in a single fossi l sample, in Ipomoea pollen grains only. The first author, examining this assemblage of pollen grains for the first time, was amazed to come upon a large, smooth, almost perfectly spheroidal hollow object with large, nearly circular perforations in it (Plate XI, 7). Further examinati on of the sample showed that this object was a pollen grain; corresponding pollen in good condition with intact exine and spines ide ntified as that of Ipomoea was fo und, as well as pollen which was only partially degraded in the same manner as the fi rst. This for m of degradation had thus removed the spines at thei r roots, leaving the circular perforations, and had apparently removed the entire sexine leaving the smooth, homogeneous nex ine untouched. (The reverse of this type of pre_?ervation has been foun d by Erdtman, 1970, who found fossil pollen gra ins in mineral soi l underlying raw humus in Swedish Lapland which were present only in the form of thin sexinous films or fragments.)

The pollen diagrams

Theoretical considerations Pollen diagrams, which show the percentages of the pollen of individual taxa at any one stratigraphic level and also their fluctuation in time, have historically been in-

,I I

220

A. S. BARTLElT AND E. S. BARGHOORN

terpreted as reflect ing the relative abundance of the vegetationa l components at any specilic t ime. Changes in the percentage of a pollen type in time, therefore, have been considered to para llel changes in the rerecntage composition of the vegetat ion. This interpretat ion has been challenged from time to time since the development of the method of pollen analysis by Von Post (1916). Hessel man (1916), in the discussion which fo llowed Von Post's presentation o f the method of pollen analysis in Stockholm, challenged the assumption that a change in pollen percentage o f a species invariably reflects a parallel change in the abundance of that species in the vegetation. Fagerlind (1952), in his detailed discussion of the theory of pollen analysis, suggested reasons for the lack of direct correspondence between changes in pollen percentages and changes in the abundance of the vegetation generat ing it. The most outstand ing of these is that diffe rent species vary widely in their pollen production and dispersal capabilities. Under ideal cond itions, compensating correct ions can be made for dissimilar production capacities of various species. Fagerlind enumerated anumber of conditions which must be satisfied, however, if pollen diagrams elaborated from data corrected for the above-named factors are to be true representa tions of vegetational change. These conditions, which have been reviewed b_y Davis (1963), in her discussion of the theory of pollen analysis, may be stated briefl y as follows. (1) The area delivering pollen must be homogeneous- that is, it must consist of components having "uniform edaphic conditions, uniform vegetatio nal history, etc., etc." (Fagerlind, 1952, p.l93). Tf this cond ition is not satisfied "conditions become extraordinarily complicated" (p.l94). Fagerlind emphasizes that if variable edaphic conditions or "blind spots"-areas where the species considered in the pollen diagrams are absent- exist in the delivery area, interpretation of the pollen diagrams becomes particularly difficult. If considerable heterogeneity exists, states Fagerlind, changes in the vegetation ratios become almost impossible to reconstruct. (2) Pollen received at the sam pl ing site must represent a complete sample of the vegetation of the delivery area. (3) A ll pollen reaching the sampling site must be preserved-no differential loss may take place between the time of deposition and that of sampling. Furthermore, no differential loss must take place during sample preparation. And, of course, identification of the pollen must be correct. Fagerlind took an extremely pessimistic view o f investigations in which the conditions outlined above are not satisfied. R econstruction of vegetation from pollen percentages was considered possible b y him only if the pollen delivery area was homogeneous. H e considered such reconstruction uncertain or impossible, however, if considerable heterogeneity existed. H e expressed the opinion, furthermore, that if the object of a pollen study is to study vegetation and climate, and considerable heterogeneity is found to exist in the pollen delivery area, the investigator should consider seriously the advisability of continuing the study. Elsewhere in his paper, he has injected a more optimistic note, saying that a knowledge of the ecology of the species included in the pollen diagrams and of the topographical and other charac-

PH YTOGEOGRAPHIC HISTORY OF T H E ISTHMUS OF PANAMA

221

tcristics of the delivery area may somet imes red uce the d ifftcult ies. The primary need for reasonable interpretation of pollen diagrams, according to Fagerlind, is "for common sense". Jn his d iscussion of po llen diagrams, Fagerl irrd fa iled to consider the possibility of their interpretati on on the basis of qualitative rather than quantitative changes. Interpretation of diagrams in which the species composition varies from one level to another, with the pollen of certain species completely replacing that of others, must reflect parallel changes in the vegetation. For example, the change in the Panama diagrams from domination by Rhizophora pollen to a predominance o f fresh-water swamp plant pollen must reflect a change from mangrove vegetation to fresh-wa ter vegetation. One can make no reasonable inference, however, about the relative abundance of species within the swamp vegetat ion from the percentage of pollen of each type, nor about the extent of the swamp. (fnfcrences about the probable extent of the swamp may be made on considerations of topography and o f distribution of peats and ot her sediments in the area.) Addi tion al evide nce that the swamp existed at the sampling si te a nd not at a distance may come from macro fo~sils; in the Panama samples, seeds very closely resembling those of Jussiaea natans, a fl oating aquatic, were found in a sample conta ining Jussiaea pollen. In the lower parts of the diagrams, pollen present is that of rainforest trees; here again, one can logically inter pret this as representing rainforest vegetation, judging also from the virt ual absence ofÂˇother pollen such as that of the fresh-water swamp plants. The relative abundance of species in the rainforest vegetation cannot, however, be determined. The presence or absence of certain p ollen types may also be highly significant to climatic interpretations, quite independen tly of their frequency. Good judgment must be exercised, however; the absence of a diagnostic species having low pollen production from a si ngle sample in a series in w hich it is other wise p resent must not, for example, be interpreted as proof that t he species was not p resent. Its absence may, instead, represent a sampling artifact. If, however, the absence of such pollen is prolonged, extending over a period of many h und reds or thousands of years, it is probable that the species in question did not grow in the area at that time. Some of the conditio ns outlined by Fagerli nd as being p rerequisite for data providing a basis for pollen diagrams s usceptible of valid interpretation are not met by the Panamanian material. This is shown by a consideration of the modern pollen rain and of the topography and sedimentary hist ory of the Gatun basin. Interpretations of the Gatun basin diagrams will be based, therefore, on comparisons of the qualitative compositi o n of the pollen flora from one stratigraphic level to another, on the ecology of the component species, a nd on topography and otl1er characteristics of the source area. I nterpretations will be based on quantita tive considerations in the case of Rhizophora, where previous investigations have shown this to be admissible.

222

A. S. BARTLETI AND E. S. 13ARGHOORN

f'HYTOGEOGR A I'H!C HISTORY OF T H E ISTHM US OF PANA MA

223

The Ca1iut Basin diagrams

TABLE Il l OCCURitEN CES NOT SII OWN ON I'OLLI'N DIAGRAMS

Pollen d iagrams have been constructed in the traditional manner, with the percentage of each sporo morph plotted against the d epth of the sample from which it was extracted. In these diagrams (sec Figs.7- IO) the depth is expressed as feet below s~a level, and percen tage scales arc included where necessary. Several of the most abundant po llen types, presented at tbe left of each diagram, are plotted on a scale onehalf that of the less abundant types, in o rder to conserve space. A number of additi011:1 l infrequen t pollen types are not shown on the pollen diagrams. These are presented in Tables II- Y. A significant departure has been made from the traditional pollen diagram in that the pollen types present, but not represented among the 200 gra ins counted in each sample, are noted on the diagrams. This procedure was followed as pollen types signi ficant to the interpreta tion of the vegetational and climatic histo ry o f the area were o fte n present in the sample in frequencies too low t o appear in a count of 200 grains. A n add itional though minor departure from tradition is that pollen types included in the 200-grain count but having a frequency of I % _o r less are represented by a dot; th is procedure is followed p urely fo r the sake of clarity. Curves showing the variations in frequency th rou~ h time of two of the major

Core TDS-4

Sample 1111111bers 78

1!9

Liriosma Hytlmngea Bauhinia emargiuaUt Caua.•alia Drepa!rocarplts-typc Pterocttrpus-typc Byrsonima

p p

0 .5

Polygalaceae

G/ycydcntlron Cupa11ia Couroupita Combrelum Merremia Utricularia Aphelandrtl Triclumthera Borreria Sechium edule-typc

i> p

0.5 p p p p p

- -Sample mtmbers

140

146

- - ------- -- - ---- Phytelephas Coccoloba-type Mvflugo

Cro tonoid euphorb.

. ...

Cissus Tetracera Maripa Cordia a/fiodora · .. Justicia Mendoncia p =present.

-· p

p p

Portulacaceae Menispermaceae Annonaceae

Compsoneum Tristidw Hydrangea Colliandm Erythrina Mucuna Quassia Manihot

p = present; n umbers given arc %of pollen sum of200 grains.

OCCURR ENCES NOT SHOWN ON P OLLEN DIAGRAMS

Core TDS-2

100

0.5

TABLE II

- -- ---

--·----·--

pollen components (and presumably, therefore , also of the major vegetational compo nents), Rhizop!torii and the Urticales, appear in the fou r pollen diagrams. An additional diagram (Fig.3) has been constructed to show major fluctuations in the other two basic vegetational groups- the ty pi cal rainforest trees and shrubs, and the fresh-water swamp plants of all types.

p p p p

TABLE I V OCCURRENCES NOT SHOWN ON POLLEN DIAGRAMS

p p

Core SL-48

p p

p p p

p p

p p p p

p p

Sample 1111111bers 4

Catopsis Licania arborea Drepanocarpus-ty pe Gyranthero dorieneusis-type Couroupita tVfalouetia Raudiasp.

p p p 0.5 p p

p = present; numbers given are %of pollen su m of 200 grains.

A . S. BARTLEIT AND E. S. HARG HOORN

224

PIIYTOG EOGRAI'I IIC H ISTORY OF T HE ISTH MUS OF PA NA M A

Fig.8, 9, and 10 each include only samples from a single co re. Fig.7, however, is a polleo diagram elaborated from samples originatin g in fo ur different co res. None of the cores individually contained enough samples below aboutlOO ft. bea ring sullicicnt well-preserved pollen to provide an adequate picture of vegetat ional change d uring t his early period. Therefore, samples from the fo ur co res were combi ned in a si ngle diagram, which presents an approximate indicat ion or vegetational change in this interval. Incorporation of samples from the fo ur cores into a single diagram seemed justified fo r several reasons. First, three of the fo ur were less than abo ut 3,500 ft.

I UfU l l h'

II "~

t llkl

....1 +

r~ na. -.-Jh f

· 10

~-u• 1• 1•1~ uu

Cores UP-25-CC, SL-103, SL-104, SL-105

Liriosma

Crotonoid euphorb. Malvaceae

Buettneria Couroupita Cassipourea Jussiaea

123

0.5

p p

ii \ ......

1.5 p

I\ • +

0.5 p

•o

I •,,

p p

100

p p

......

...,

..:_s::.;;.

.. ... --.

· - - - -·

(\>I n

Sl... U).\. SJ., JU-1, !'ll· IUS

:tl ~ l rt"· !S.('c· ~~•nll:•lh<J

: ,:.'

y1,, ·/

+ /

p p

Apocynaceae

Tabem aemontana Justicia Randiasp.

170

•O

_....-·

·--."-.._

"'-..... ....I. ...........

Amaranthaccac Annonaccac

Hydrangea Canal'lilia DrepanaCllffJIIS-Iype Leucaena multicapitula MIIC/1/la Pterocarpus-typc Quassia Vochysia

Sample 1111111bers 126 27 130 28

IY•>hto~.·\oi iiUi ~nol oJu'~"

TABLE V OCCURRENCES NOT SHOWN ON PO LLEN DIAG ilAMS

2.25

100

: .''

110

I'\

110

llO

140

••

\ J

•

.-10%

p = present; numbers given are% of pollen sum of200 grains.

apart (seeFig.2); of these three, two were separa ted by only about 500 ft. The fourth core, situated at some distance from the others, contributed only a single sample to the diagram. In addition, most of the samples contain pollen (aside from that of Rhizophora) predominantly of rainforest trees (Fig.3). A lack of herbaceous and swamp pollen types, co upled with the fact that all the pollen types with the exception of that of Iriartea and Alchornea occur in very low freq uency, suggests that the pollen rain at this site was regional rather than local in character. The pollen rain during this interval sho uld, therefore, have been comparable at all of these sites.

Fig.3. Change of major vegetation types in lime.

The modem pollen rain A number of samples were taken from surface sediments in Gatun Lake near the shores of Sarro Colorado Isla nd ·(Fig.2) in order to determine the characteristics of the modern pollen rain. Of twelve samples processed for pollen, only five yielded well-preserved pollen in sufficient qua nt ity for analysis. The remainder were either sterile, or contained only very poorly preserved pollen. As some of these samples were highly orga nic, the reason for t his paucity or absence of pollen is not clear. It is possible that aerobic bacteria are responsible for the destruction of the pollen in the samples containing only a few corroded grains, as t hese conta ined little evidence of fungal activity.

226

A. S. BARTLET T AND E. S. BARG HOORN

Pollen counts from fo ur of the pollen-bearing samples were made: all conta ined very llb undant , beautifu lly preserved grains. Fig.4 shows the relative abundanc e of pollen grains or din'crcnt typcs included in the 200-grain count made or each sample. It docs not include other types prese nt but not found among the grains co unted; these arc listed in Table VI. It may be noted, fi rst of all, that on ly a few pollen types arc presen t in any

(;, .. ,... no.: r~ 1...··~.-"~" l'~tuu~

.-lim" llrllt,<ll.: • n,.vuJ,oAJ t\UIIVI!;I\"c.';!<'

{j.,,,,,, .lffjl(J.f <Wt'f'-"U·I)'I,.. !ol,m...,.,ollk'H

,.,,. (..,

l 'lr.-,vo~l<rtrfJi l'>- l}pt

/,~m/ho 'tt'lr"llf\lllJIII<',ot''

/..,..,.,..,,.tit,

l~ '"'"'""''u. ...)t"''

)k~J .OC'·S~t.,''" •'' ~•·

~I:Jtj•I,IIU<'t:U.'

__.,,,, ,,~.~ Alo l•oi'JH"o~

/f,..,,.,,mJ IJilf"J

cu,um.l J'.ml/lllt'll ,..;..rjJN<I

.·lt..-J!.I Irl•••""'''' / .rn·IJo'J\o'(lllJIItlil I~•HJIVo"f"l'

Urltf•.,*' I"..1Mt/t.m1IJJ.f ()fwr,mlmt /iiH'IfHffiiJ Ttl~ow·o~

Otmllo CJ!fWft'IOO.lloH\U 1i'l,l/o'f.~/f;J

Sxmt''"'''i.l

Wu..-.op~r..,, )l( b )oltliiU tJt<..t

(i~toh'J,Hi• >cl••f<f

l·iu'''"" ,., 11/lfll "'l;tro.•

- m

Fig.4. M odern pollen rain as shown by surface sedimenls. TABLE VI POLLEN OCCURRENCES NOT SHOWN IN FIG.

Conovalia Polygalaceae Sapiwn Cavani/lesia Ceiba Lafoensia Mendoncia Alibertia Cosmibuena pa/udico/a

I'HYTOGE OGRAPH IC H ISTORY OF TH E ISTHMUS OF PANAMA

227

appreciab le percentage. Among these arc pollen of the Urticales, Prioria copaifera , Zallllwxy lum pwwmem e?, Z. semlusum , Acalypha , Alchomea , Apeiba Jibourbou, Luehea seemwmi i, Cordia al/iodora, and the Melastomataceac. Of these the Urticales

(mainly Moraceac such as Ficus and Cecropia, and 1i·ema of the Ulmaceae ) are consisten tly abundant in all fou r samples. The remainder show more varia tion fro m sample to sample, apparently reflecting a mo re localized aspect of the pollen rain. Prioria copaifera is an ou tstanding exa mple of local over-representation of a pollen type; it has a frequency or about 72% in sa mple 21-1, bu t is not present among the pollen counted in the other three, which are loca ted abou t two miles from this sampling site. Although general agreemen t among the three samples situated within about 500 yards of each other (26-1, 26-2, and 24-2) is excellent, local influence of a lesser extei1t is detectable. Pollen of Luehea seemannii, wh ich is co mmon in sample 24-2, does not appear in the other two. Pseudobombax polle n, which appears among the counted pollen only in sample 26-1, undoubtedly originated from a large tree of this genus noted growi ng in the vicinity of the sampling site. Al though the pollen frequency of each or" the most common types mentioned above varies somewha t from sample to sample due to local influence, the common types in th is suite or samples as a whole reflect the more ab undant species in the vegetation to some degree. Prioria copaifera, for example, may be locally abundant , and may actually form nearly pure stands. The Urticales are among the more common elements in both second-growth and mat ure forest vegetatio n. Zanthoxy lum panamense"! (see annotated list of species) pollen is abundant ly prese nt in the samples; Z. panamens e is among the fo rest dominants listed by Kenoyer ( 1929), as is Prioria copclifera . Z. se!ulosum is described as common by Standley (i928). Luehea seem01mii, Apeiba tibourbou , Cordia alliodora, and Melastomataccae are all noted by Kenoyer as among the trees prominent as pioneers in cleared areas. The surface sediment samples demonstrate, therefore, <hat although the common types in the enti re su ite reflect some of the more abundant elements of the vegetation, strong local infl uence as well as pronounced local over-representation ex ists in the pollen rain in individual samples. On ly a few pollen types are relatively abundant in a ny given sample, and these, due to local vegetational differences, may thus be those of totally different species at each sampling site. These character istics of the pollen rain apparentl y reflect the mosaic nature of the rainforest vegetatio n growing in the area. This tropical forest vegetation, unlike that of the typical temperate forest, may contain numerou s species in a small area , and one after another of these may achieve prominence from one site to another. In temperate deciduo us forests, on the other hand, a few arboreal species are dominant over large areas. A high percentage of the modern pollen rain fro m such forests may consist likewise of that of a few species (which may not, however, always be the most abundan t species of the vegetatio n). Vegetatio nal history of such regions is interpreted, therefore, on the basis of changes in . the frequency of these common pollen types. Jn the northeast ern United States, for

228

A . S. BARTL ETT AN D E. S. OARGHOORN

exa mple. inferences about vegetat ional change over the past 10,000- 11,000 years have bee n based primar ily o n changes in relative freq uency or the pollen or spruce, fi r, pine, oak, birch, hemlock, maple and chestnu t. The pollen rain from the vicinity of Barre Colorado Island indica tes tha t a dill"crcnt approach, the qualitative approach outlined above, rather than a quantita tive one, must be used in the interpretation of the pollen diagrams elaborated from data obtained fro m the Gat un basin deep cores. A quantit!tti ve approach is impossible, on the gro unds that, given the complexity of the tropica l rainfo rest, correction factors relating pollen prod uction to frequency in the vegetation of the species involved arc ruled out. Furtherm ore, the conditions that must be satisfied if such corrections a rc to have validity arc not satisfied, given the topographical variability and vegetational and edaphic heterogeneity whkh have characterized the Gatun basin du ring the past 12,000 years.

Climatic change in Panama Difficul ties in interp retation of past climates on the basis of pollen evidence are not limited solely to th ose posed by th e inherent properties of the pollen diagra ms. Cli matic interpretations must be based, above all, on a kno wledge of the present distribution patterns of plants, and on an understa nding of factors governi ng such dist ributio ns. Therefore, in order to detect di!Terences between present and fo rmer plant di stributions in Panama, the present geograph ical range of members of the flora must Âˇbe known. Furthermore, factors controlling distributions must be recognized in order to determ ine whether a change in the range of a given species sh own by the fossil record was caused primarily by climat ic fluctuation, or was due instead to variations in edaphic condi tions. Although extensive collections have been made of the Panamanian flo ra, the geographical range of most members is imperfectly known at best, and an understanding of facto rs governi ng their distribution is li mited to a very few species. Th is fact makes the in terpretation of past climates very d iffic ul t. Additional difficulties are posed by a number of factors, outstanding among which is the fact that species identifications of pollen_often cannot be made. As many tropical genera have numerous species, each of which may be adapted to an entirely different habitat, generic identification of the fossil pollen is often insufficient to allow its use as a precise climatic ind icator. The fact that specific identifications often may not be possible is true for several reasons, outstand ing among which is the fact that time and resources do not permi t the acquisition of a complete pollen collection. Even if this were possible, discrimination among all the species of many genera probably would not be possible on the basis of pollen morphology. Some limitation may be placed on the use of the pollen record as a key to climatic

PHYTOGEOGRAPH IC HISTORY OF T H E ISTHMUS OF PANAMA

229

history d uring the past several millen nia, at least, hy the interference of man with the nat ura l vegetation. This may be true in Panama, where ex pansion of grasses .and Composite herbs during_the past several thousa nd years may be due to agricultural activities; this expansion in some of ou r sa mples is so pronounced that all other evidence of climatic change is obscured. An additional problem is presented by the fact that cdaphic conditions in the Gatun basin weÂˇrc drastically altered during the period tinder study by the rising sea level. Vegetational changes caused by climatic fluctuations would, therefore, be superimposed on the more profou nd cha nges brought about by the transition from sa lt-water to fresh-wa.ter conditions. In view of these li mitations, .inferences about postglacial climatic change in Panama a re based on the rather conspicuous changes in range of a very few species, which apparently had a much greater range in late-glacial and early postglacial time. The distri butions of plants on which infe rences about climatic change a re based are evidently controlled primarily by temperature, as their present ranges are apparently limited by altit ude. identification and nomenclature ofthe .fossil pollen An extensive collection of modern pollen of-Central American species, with particular emphasis on those of Panama and Costa Rica, formed the basis for the identification of the fossi l pollen. Pollen slides already in the Harvard Pollen Collection at the beginning of this study were supplemented by additional material collected pri ma1ily from specimens of Cent ral American plants in the Gray Herbar ium and the Herbarium of the Arnold Arboretum. Fresh pollen of a comparati vely small number of species collected in Panama also supplemented the pollen collection. Pollen of each of the total of about I,500 species represented was studied in detail and descri bed on a Uni-sort punched card, using a much-modified and refi ned version of Faegri and Iversen's (1964) perforated card key method. T he cards, most of which feature also a camera-lucida drawiirg or photograph of the pollen described, were used in all cases only to limit the number of possibilities for identification of each fossil type. Final identi fications were made not by comparing the unidentified grain on ly with the descriptive card, but by comparison with the corresponding pollen itself. Making of the perforated cards was a very time-consuming task, bu t well worth the effort. The cards proved to be invalua ble for the identification of the numerous kinds of fossil pollen encountered in the sediments, and were fou nd to be the only practical method fo r carrying out this task. Study and identification of the fossil pollen was made with a Wild M-20 microscope. Photomicrographs were made with an Ex acta camera on Kodak M -135 (highcontrast copy) film or Adox KB-14 film. Kodak M-135 fi lm was -found to be most satisfactory for grains showing detailed exine structure, while Adox KB-14 was excellent fo r giving good representations of grains with little sculptural detail.

230

A. S. BART LETI AN D E. S. BA RG HOORN

PH YTOGEOGR AI'IIIC HISTOR Y O F T HE ISTH MUS O F PANAMA

I'LATE I

All idenlilkdJ.ypes arc figured on Plates I-XI II. A br ie f description of each type is included in the plate explanations. Identified famil ies, genera, or species <H'C listed add it ionally in the an notated list at the end of th is section which includes a brief ecologica l characteri Z<ttion of each, with occasional notes on pollen, where applicable.

231

Nomenclat ttrr:

Nomenclature of the fossil pollen follows pri nciples set forth by Zagwijn (1960), slightly modified . Briefly, these arc as fo llows: if a fossil pollen type is assigned to a given recent na tu ral taxon, this expresses a high degree of confidence in the id entification. If the word "-type" is appended , however, it indicates that the given type is known to occur, or may occur also in a related taxon of the same rank. Thus, for example, Erythrina glauca indicates that most of the Erythrinas of Panama have been studied, and that E. glauco is sufficiently d istinctive as a species to be identified as such in the fossil form. Catopsis morreniana-type indicates that, of the species of Catopsis studied, the fossi l form corresponded very closely to this species. As there was uncertainly, however, that sufficient species of this genus had been studied to warrant a positive identifica tion at the species level, the word "-type" was appended .

Explanation of Plates I-XIII

Each pollen type, unless otherwise indicated, is 460 x. Exine detai ls are 720 x . Micrometer sca les showing 20 11. at 460 x and = 720 x are given on Plates I and I I, respectively. 9

''6 '

Âˇi

Typhaceae

1. 2.

3, 4.

Palmae

5, 6.

Typha: no. 61, ca. 45tt; monoporate , reticulate, muri simplibacula te. Gramineae Maize: no. 14, ca. 110 p.; no te the pore in the upper fold to the right of center. Cyperaceae Cyperaceae. 3: no. 26-1, ca. 38 p.; monoporate , pore poorly defined; scabrate. 4. no. 6 1, ca. 60p.; monoporate .

Cryosophi/a: no. 100, ca. 50!'Âˇ 5. high focus; 6. Co!pus. Monocolpate, reticulate; occasionally

trichotomosulcate; muri duplibac ulate, except nearcolpus . 7-9. friar tea. 1. no. 72, ca. 45 ,u. 8;9. no. 100, ca. 43 p; monocolpate, clavate. 10. Pltytelepltas: no. 100, ca. 125!'; monocolpat e, reticulate; muri simplibacu late. II. Socratea-type: no . 123, ca. 55ft; monocolpate , echinate. 12. - Palmae, unidentified: no. 24-2, ca. 65 /t; monocolpate, exine heavy. Pontederiace ae 13. Pontederiace ae: no . 76, ca. 43Jt; dicolporate, exineareoloidate. Araceae 14, 15. Anthurium: no. 57, ca. 23 11; spheroidal (this specimen is squashed), 3-porate, retipilate. 14. high focus; 15. mid-focus. Bromeliacea e 16, 17. Catopsis morreniana-t ype: no. 4, ca. 65 1-1; monoco lpate, retic ulate; muri simplibacula te: reticulum very regular. Piperaceae 18 . Pipcraceae: no. 141, ca. 15 p; monocolpat e, scabrate. Ch toranthaceae 19, 20. lfedyosmum: no. 68, 28 p.; monosulcoid ate; spheroidal, retipilate. 19. high focus; 20. midfocus .

232

A. S. BARTLETT AND E. S. BARGHOORN !'LATE II

233

Vcxetalioll 35,500 B.P.

50 '

'\.. ··J'.... l . Jlll -.,,,,,.,

':;..i .I•1 ··· ~· :·" '.j

I'HYTOGEOGRAI'HIC HISTORY OF TH E ISTHMUS OF PANA MA

.:J' 16

I .II

A sample of th is age is rendered particu larly interesting by its antiq uity and its relationship to sea level at the time of deposition. Its age, 35,500 :l. 2500 O.P., suggests a possible correlation wi th the American and European interstad ials of approximately thi s age disc ussed later. The sample (no. 123) lies just below a deposit iona l unconformity sepa ra ting it from the next dated sa mple situated 5 ft. higher in the core, at 158 ft. below p resent sea level. Th is sample (no. 30) was dated at II ,300 :1: 200 B.P., providing ev idence of a long period during which no sed imenta ry deposition took place at thi s si te, corresponding to a period of Wisconsin low-sea level. Pollen present in the 35,500 year old sedimen ts is predominantly that of Rhizophora, which co mprises 74 % of the total pollen. Additional pollen present in the sa mple is that of fo rest trees, including Alchornea, Luehea, Ochroma, and A ricennia. Also present in this sa mple is pollen of several taxa not typically growi ng in the Canal Zone at present, the Ericaceae, flex, and Podocarptts. Presence of the Eri caceae implies that these plants grew at elevations ca. 500 m below the present lower limit of their range, suggesting that temperatures during this period were ca. 2.5°C lower than those of the Canal Zone today (given the altitudi na l atmospheric temperature lapse rate of ca. 0.5°C per 100m (Wright, 196 1). The very high percentage of Rhizophora pollen in this sample indicates deposition

4. 5.

Trema-typc: no. 80, t a. 21 tt; diporate, scabratc. Urticaceae: no. 100, ca. 23 /i; 5-porate, p si late.

Oryl'tautlm" cord({o liu.r: no. 24-2, ca. 40 11; tetrad , struc ture peculiar and unclear.

Lirio.\'IIW: no. 100, ca. 50!'; triporate; note thi n exine area at pole, fi nely scabrate membrane

Loranthaceac Olacaceac

19 covering pores.

· Chenopodiaceae Chenopodiaceae: no. 68, ca. 23tt; spheroidal, periporate. Amaranthaceae Altemaulhera-type: no. 58, ca. 251'; fenestrate. 9. Gomphreua-type: no. 8, ca. I3 Jt.; fenestrate. 10. Po lygonaceae 11 - 14. Coccoloba-type: no. 170, ca. 43 f<; t ricolporate; exine pattern d istinctive, complex. 12-14. Exine at high-, mid-, a nd low focus; x I ,000. Polygouum: no. 61, ca. 70 J.L; polyporate; coarsely reticulate, with pores present in some of the 15. lumina; walls of reticulum covered with wart-like excrescences elongated radially. Aizoaceae Mollugo: no. 95, ca. 35~t; periporate, irregularly spheroidal ; pores elongated, scabrate. I 6. Menispermaceae 17, 18. Menispennaceae: no. 68,ca. l 6~t; reticu late, tri porate. Po rtulacaceae Portulaca oleracea: no. 65, ca. 90 p; pericolpate, spinuliferous. 19. Ann onaceae Annonaceae: no. 7, ca. 400 p; tetrad, loosely joined; x II 0. 20.

Betulaceae I.

Alnus: no. 97, ca. 38tJ.; s tephanoporate ; pores 3-6 in number; arci extend from one pore to

another, around the equa tor of the grain. Myricaceae Myrica: no. 64, ca. 30 I'; 3-4 porate, slightly scab rate to ps ilate. Urticales Ficus: no. 26-l , ca. 1 5~t; diporate, elongated, psilate.

• 234

A . S. BARTLF.H A ND E. S. BA RGHOORN

PHYTOGEOG R AP H IC H ISTO R Y OF THE ISTHM US OF PANAMA

PLAT E Il l

~35

in a mangrove swamp-al-sea h:vel, and t hus suppo rts other evidence of an interstadial high sea level about 35,000 years ago . Vegetation 11,300- 9,600 B.!'.

.,'

iI rl·":",..- ~. <----.. .

r.t·

..l

; . 1 ...

~.:

···.

~~·

l !

14 .

Pollen deposited during this period is pred ominantly that of rai nforest tree genera, includ ing fo r example Phyte/eplws(an ivory palm), Dialyantllera, Virola, Copaifera, Swartzia, Bw·sera, Lafoensia, and members of the Bombacaceae (Fig.3, 7) . Pollen of fresh -water swamp vegeta tion is very rare,and the pauci ty of Rhizoplrora pollen indicates a poorly-developed mangrove vegetation, which may have been inhibited by the rapidly rising sea. During this interval, pollen of the other mangrove genera, A ricennia and Conocarpus, and that of the fern Acrostichum, is also uncommon. Abundant pollen types during this interval include those of the Urticales, lriarrea, Alchomea, and Rhizoplwra. Pollen of the Urticales incl udes that of Ficus and Cecropia, and represents vegetation cha racteristic or disturbed gr0t111d. The presence of the pollen of Alchomea at consistently high frequencies during this interval is unusual. Alchom ea pollen is present throughout the entire late-glacial and postglacial record in these sediments, but never again reac hes the high fre quency attained duri ng this early period. The abundance of this pollen is puzzling, as no references to forest stands in which this gen u~ is predomina nt arc to be found in the literature, nor have such occurrences been observed in the field. Of particularly great interest among the pollen types present during this period is that of IriGI·tea, one of the .so-called sti lt pal ms. As lowland species of this genus apparently do not exist in Panama today (see the annotated list at the end of this section), it is possible that this pollen provides evidence of a forme rly extended ra nge of the genus. T he only representative of this genus known to exist in Panama today is l riartea

iI'

I r

2. 3. 4.

Annonaceae Annonaceae: no. 6, ca. 170 t• ; x 325. Myristicaceae Dialyanthera: no. 68, ca. 55 p. 2. high focus; s ide of grain o pposite colpus; 3. mid-focus,colpus at bottom of grain; sculpturing at top consists oflong papillae, reticulum elsewhere. Virola ty pe U : no. 73, ca. 17 p.; monocolpate, retipilate.

5. 6.

Virola type I: no. 92, ca. 38!•; rnonocolpale, reticu late; muri simplibaculatc . Compsoneura: no. 72, ca. 37 I' ; monocolpate, retipilate. Saxifragaceae 7. Hydmngea: no. 68, ca. 12Jt; tricolporate, rctipilate. Podostemonac eae 8, 9. Podostemonaceae: no. 72, ca. 23 1•; spheroidal, periporate; pore membranes scabrate. 8. high focus; 9. mid-focus. Rosaceae 10. Licania arborea: no. 6, ca. 40 ;•; tricolporoidate, exine rough; amb of fully expanded grains triangular. Leguminosac II , 12. Mimosoideae: no. 79, ca. 25 J<; planar tetrad, scabrate. 12. no. 79, ca. 25 J.t; planar tetrad, psilate. Both of these pol len types appear in the gen us Mimosa. 13. Calliandra: no. 68, ca. 215 p.; polyad, 8-celled; exine reticulate; x 230. 14. l..eucaena multicapitula: no. 72, ca. 105 p.; polyad, 16-celled; reticulate; reticulum d istinctive. 15. M imosoideae: no. 64, ca. 120 I'; 16-celled polyad, exine psilate.

236

A. S. llARTLEH AND E. S. BARGHOORN P I.ATI: IV

PHYT OG EOG RA PH IC HISTORY O F TH E ISTHM US OF PANA MA

237

This spedes, which occurs in the [(>rests of Da rien Province al altitudes of I,200- 1,500 m (4,000- 5,000') seems to occur a l hi gh allitudes only. Presence of its pollen at sea level implies, therefo re, an a ltitudina l cx tensi_on of its ra nge. The limits of its range would, the refore, have been lowered by about 1200 m (4,000') if the palm grew at sea level, and ca. 900 m (2,900') if it occupied the summits of the highest hills of the Canal Zone a rea. Additional scattered occurrences of the pollen of plants not presently found in the Ca nal Zone include Alnus, Podocarims, Symplocos, and Ericaceae, all found at very low freq uency. Pollen of the llr~t two is found occasionally througho ut the entire sedimentary column and also in the present po llen ra in, and undoubtedly was carried to the Gatun basin by long-distance tran sport from the hills of Panama. The. presence of the las-t two pollen types is very interesting, as neither of these has representat ives in the Canal Zone today. S ymplocos is presently con fined,j~dgi ng from al titude no tations on specimens in the Gt ay Herbarium of Harvard University, the Arnold Arboretum Herbarium, and the National Herbarium, to altitudes above about 1,000 m (ca. 3,300'). Pollen of the Ericaceae in these sea-level sediments similarly implies a for mer extension of range of so me members of thi s fami ly. Herbarium collections indi cate that these plants do not at present occupy habitats below 500 m (I ,650')_above sea level. Occurrences of members of th is fami ly a t such low elevations are apparently exceptional in Panama (see the annotated list). Pollen evidence of lriartea, Ericaceae, and Symplocos at elevations fro m ca. 500 to 1,000 m below that of their present lower range limit suggests that temperatures du ring this period, fr om I I,300 to 9,600 B. P., may have been at least 2.5°C lower than those prevailing in the Canal Zone today. coruelo.

.....

- - - ---- -·-- - - ---------5. 6-8. 9. 10, II. 12. 13. 14- 16. 17, 18.

Leguminosae I. 2. 3, 4.

Bauhinia emarginata: no. 68, ca. 110 ft; spheroidal; num ber of apertures not clear; exine

gemmate; x 3 15. Mucuna: no. 140, ca. 95~~; tricolpate, pro late, reticulum complex. Can~valia: no. 26-l , ca. 55 p; 3. high focus; 4. section. Tr icolporate, oblate; heteropo la r; frustiJiate at one po le.

Macrolabium: no. 123, ca. S0 1r; tricolporatc, pores fa int; striate. Prioria copaifera: no. 21-1 , ca. 30 /r. 6. oblique view; 7. polar view; 8. equa torial view. Erytlrrina s p. : no. 51, ca. 40 I'; very similar to £.glauco; triporate, oblate, reticulate. Erytlrrina s p. : no. 140, ca. 35Jr; very sim ila r to£. costaricensis; t riporate, oblate, ret iculate. Swartzia: no. 65, ca. 30 ,, ; tricolporate, sphe roidal; syncolpate, col pus membra ne scabrate. Capaifera: no. 100, ca. 281•; oblate, tricolporate; amb subtriangular; psilate. Drepanacarpus lrmatus-type: no. 79, all ca. 18J.r; tricolporate; pore endexinous; reticulate. Pterocarpusajficinalis-type: no. 26- l,ca. t 81r.. l?. high focus; operculum may be seen in this

view: 18. mid-focus; spheroidal, tricolporate, operculate. Exine finely re ticulate. Rutaceae 19- 23. Zantlraxyltrm pauamense? no. 9, ca. 30 I'· 19. oblique view; 20. pola r view, high focus; 21. polar view, m id-focus; 22. equatorial view, high focus; 23. equatorial view, mid-focus. Exine retipilate. 24, 25. Zanthoxylum setu/asum : no. 68, ca. 25 p. 24. Focus on far side of grain, col pus; 25. high focus, equatorial view. Striate; striae are especia lly parallel close to the col pi. Quassia: no. 126, ca. 40 p; two grains; tricolporate; exine reticulate, striata -reticulate at 26. a pertures.

238

A. S. B;\ RTLEn · AND E. S. IIA RGI IOORN

PHYTOG EOGRA PH IC H ISTOR Y OF T H E ISTHM US OF PANA M A

PLAT E V

VegcJatioll 9,600-7,3 00 B.P.

The next period, from ca. 9,600- 7,300 B.P., is charactcr!zcd primarily by the abu ndance of Rhizophora pollen, which comprises as much as 9 1:%'. or the pollen sum. Depositio n in a well-deve loped mangrove swam p is therefo re indicated. Pollen of two species characteristica lly associated with Rhizopliora in mangrove swa mps, A •·icennia and Conocarpus, is also more abundan t d uring this period than at any other ti me. Acrostic/tum, one "species of which, A. aureum, grows in mangrove swa mps, is also abund antly represented. Iriartea pollen conti nues to be abundant during this interval, but declines gradually in frequency, fi nally ceasing to appear in the fossi l record at about 7,300 B.P. Pollen' of the Ericaceae also disappears from the record in cores TDS-4 a nd SL-48 at about 8,500 to 9,000 B.P. fn core TDS-2, however, a single gra in is fo und in sediments deposited betwee n 7,300 and 4,850 B.P. Pollen of S)'mplocos similarly ceases to appear in sediments deposited after about 8,000 to 8,500 B.P., in all three cores. J udging by the virtual absence of pollen of these three genera after about 7,300 B.P., temperatures must have reached those character izing the climate of the Canal Zone at present by the end of this period. Percentage of pollen of the Urticales conti nues to be high durh1g this interval. A great va riety of forest tree pollen is prese nt , including that of genera promi nen t in the matu re forests of Sa rro Colorado Island today. Among them are Zanthoxy lum

:6··· .-•· II 7·~ .

• I

8 ~./-,.;i

e I

239

~-i

: ...."'t I

e J I

panamense?, Luelrea seemannii, Apeiba , Alchornea , Lafoensia punicifolia, Symplron ia globulifera, Bw·sera, Hieronyma, Mabea , the Bombacaceae, and many others. The

6. 7, 8.

9. 10.

II .

· - - ·---- ----- --

---- --·- ----

Malp ighiaceae Malpighiaceae : no . 62, ca. 38 I' ; polyporate ; colpo id streaks ru n fro m one pore to a nother ; exine psilate. Byrsonima: no. 99, ca. 15tt. 1. High focus; 8. mid-focus; Note costae in this view. Vochysiaceae Vocll)'sia: no. 170 , ca. 35tt; oblate, tricolporat e; margo. Polygalaceae Polygalaceae: no. 123, ca, 43tt; oblate, stephanoco lporate, psilate. Euphorbiaceae Acalypha: no. 26-1, ca . 18 ;t.; oblate, stephanop orate, psila te; number of pores va ries from ~3.

. J

Bu rseraceae

I , 2.

Bw·sera: no. 100, ca. 30 p. l. High focus; 2. mid-focus. Striate, pores covered by ectcxinous

hood. 3-5.

Meliaceae- Sapotaceae Meliaceae-Sapo taceae, 3 a nd 5 are proba bly Sapo taceae, 4 could be either. 3. no. 68, ca. 58 p; 4. no. 40, ca. 38p,; 5. no. 40, ca. 45 p,; 3 and 4 a rc 5-<:olpate, 5 is 4-colporate .

12, 13. Alchornea: 12. no. 100, ca. 32 f<; abnormal 4-porate grain. 13. no. 68, ca . 28 t•; tricolporate , operculate; exine scabrate. 14. Glycydendronamazonicum: no. tOO, ca. 48 p,; tricolpate; exine with a fi ne croton-patt ern . 15, 16. Phyllanthus acuminatus: no. 26-1 , ca. 25;.<; tricolporate; th is pollen is un usual in having two pores per colpus. Eupho rbiaceae 17, 18. Manihot escu/enta: no. 140, ca. 170 p ; grains have several la rge pores. 18. Deta il of exine croton-pattern. 19. Crotonoid Euphorbiac eae: n o. 26-J, ca. 95 ~ ; inapertura te, sph eroidal ; exine crotono id. 20 . Hieronyma: n o. tOO, ca . 35 p,; tricol porate, reticu late.

240

A. S. UARTLETT AND E. S. BARG HOORN

PHYTOG EOGRAPH IC H ISTORY OF T HE ISTH M US O F PANAMA

PLATE VI

13ombacaccac arc particularly noticable in samples no. 100 and no. 75, in each of which six genera arc present. None is ve ry common, however. Five interesting gcn~ ra present during this period arc Couroupita, Rauwolfia, Liriosma, G/ycydeudrou amazouicwn, and Sechium edu/e-t ype. Neither of the first two are now common on the Atlantic slope of the Canal Zone, and their presence in these sediments probably represents a slight alteration of geographical range and has no decipherable climatic sign ifica nce. The pollen of Couroupiia, a genus of li mited distribut ion in Central America today, is in teresting in its uniq ue morphology (see the annotated list). Liriosma and G/ycydendron amazonicum are bot h So uth American; nei ther is present in Panama today. The Sechium edule-type pollen is identical to that of one modern collection of S echium edule pollen except in its size, as it is somewhat larger. It is unlike that of any other pollen of the Cucurbitaceae encountered, and may thus be that of "chayole", one of Panama's most common vegetables.

241

Vegetation 7,300-4,200 B.P.

Sections of the pollen d iagrams representing this interval exhibit a number of highly interesti ng features. During this period, a transition from mangrove vegetation to fres h-water swa mp took place, as a conseq uence of the slowing rate of sea-level rise (see later). At the beginning of th is period, Rllizophora pollen had already disappeared

1£7,' ' -.......... ~ ,.,.-

; •.. 0

;

•

. • ~

Euphorbiaceae 1, 2.

3- 6.

Mabea occidenta/is. I. no. 24-2 ; polar view. 2. no. 68, ca. 58 p.; Oblique view; tricolporate; exine reticulate, simplibaculate; pattern d istinctive. Sopium: no. 97, ca. 48!'· 3-6 are taken at s uccessively lower planes in the grdin, from high focus to mid-focus. Tricolporate; note the pronounced costae, which turn poleward at their ends; exine reticulate.

---- ----···- - - - 7. 8.

Hu/'(/ crepiftmi -type. 7. n o. 26- 1, ca. 68 p ; 8. no. 26-1; ca. 45 I'· Tricolpornte, costae colpi pronounced .

Anacardiaccae Anacardiaccac: no. 65, ca. 45 J1; prolate, poles generally pointed ; costae col pi usually pronounced; exine striate to striato-reticulatc. Aquifoliaceae 10- 12. flex. I 0. no. 66, ca. 32Jt. II , 12. no. 72, high- and mid-focus, respectively; tricolporate, clavate. Hippocratcaceae 13. Hippocratea volubilis: no. 6, ca. 65 I'· T his interesting and unusual polyad consists of four tetrads, joined together in a square; isolated tetrads are occasionally found, but the tetrad s themselves are a lways permanent; exine reticulate, muri simplibaculate. Sapindaccae 14, t 5. Cardiospemwm: no. 26- 1, ca . 55 I'· 14. High focus; 15. mid-focus. T he syncolpate pole is visi~le in this view; peroblate, heteropolar;exine reticulate. 16. Paullinea: no. 26-1, ca. 35 ft ; triporate, pcroblate; exine varies fro m scabrate to psilate or· reticulate, to faintly stria te. Sapindaccae 17. Serjanin: no. 26-2, ca. 30 1•; peroblate, tricolporate; sy~olpate on both poles; psilate. · 18. Sapindus: no. 40, ca. t 8 p.; tricolporate, psilate. Vitaceae t9. Cissus-typc: no. 26-1, ca. 45 p.; poles pointed; costae col pi pronounced; exine reticulate. Titiaceae 20. Apeiba membranacea: no. 74, ca. 50 p.; tricolporate, oblate; exine reticulate, muri simplibaculate; lumina often contain granules. 21. Apeiba tibourbou: no. 26-1, ca. 30 p; similar to A. membranaceo; reticulum fine: 22-24. Lueltea seemannii. 22. no. 68, ca. 30 p.; 23, 24. no. 72, ca. 38 p.; shape variable, but generally prolate; poles pointed or not ; reticulum complex. 9.

242

A. S. BA RTLETT AND E. S. llARGHO ORN !' LAT E VII

PHYTOGEOGRAP HIC HISTORY OF THE IST HM US OF PANAM A

from core TDS-"4. In core TDS-2, the freq uency of Rliizophora pollen decre_!lsed ra pid ly, soon reaching zero. In core SL-48, however, R!tizophora pollen is present in abundance until about 4,200 B.P., reflecting the greater proximity of this core si te to the shoreline of that time. Attesting to the development cf' fresh-water swamp vegetation is abundan t pollen of the Cypcraceac and Gramineac, as well as that of =Typha and Polygonu m. Also present at this time are Drepanocarpus luna/us, a species sometimes fo rming extensive stands in swam ps, and Pterocarpus officina/is, characteristically occupyin g intermittently flooded si tes. Pollen of the typically riparian Pachira aquatica is also common at th is ti me. Conspicuous for their abundance during t his period are pollen of Melastom ataceae, in particula r, and Malpighiaceae. As most genera in both of these families occurring in Panama may not be differentiated by their pollen, the significan ce of the abundance of these types is not certain. The Mclastomes, one of the largest families of tropical America, arc very importa nt elements of the vegetatio n, and numerous herbaceous, shrubby, and arboreal genera are conspicuous components of swamps, riverbanks, and lake shores (Standley, 1928). The significance of another pollen type abundan t at th is time, Ow·atea guatemalensis, is not clear. This species is not lyRically a swamp plant, but is abundant in shaded fo rests. Samples deposited during th is period arc rendered particularly interestin g and unusual by the pollen of Myrica and flex, both of wh ich are ab undan t. Myrica attains the extraordinarily high frequency of 19 % in one sample (no. 64). Presence of Myrica pollen in any of these samples even at very low frequency is notewort hy, as the genus docs not grow in the Canal Zone today. Furtherm ore, not a single grain of this genus is present in the modern pollen rain as demonst rated by the surface sediments. Its presence during this interval at such high frequency cannot be due to long-distance transport, and must indicate presence of these plants in the Canal Zone. Jlex similarly is not reported from the Atlantic slopes of the Canal Zone at present. Presence of its pollen in th.ese sedimen ts must also signify that it grew in the vicin ity at this time. lfex is not a p rolific pollinator, and the relatively high frequency of its pollen in several samples precludes long-distance transport. 4, 5.

I, 2.

Tiliaceae U nknown A. 1. no. 65, ca. 30 ;• ; 2. no. 40, ca. 321'· Pcroblate , 3-brevico lpate; re ticulate, muri simplibac u!ate; lumina contain granu les. T his pollen is probably that o f Mortoniodendro11 of which no reference material was ava ilable. Malvaceae Malvacea e: no: 26-1 , ca. 80 p; echinate. T h is pollen type is very similar to that of Hampea.

243

Malvaceae: no. 25, ca. 85 p; periporate , pores poorly defined ; echinate. 5. Mid -focus, showing spines. Bombacac eae 6 - 8. Bombacopsis sessilis: no . 68, ca. 90 ;•; oblate, 3-brevicol pate; reticulate, muri duplibaculate. T his interesting grain has two abnormal extra pores, seen towards the top third of the grain in this polar view. Exine detail (7, 8) x 1,000. 7. High focus; 8. low focus. 9 , 10. Bombacopsis quinata: no. 10, ca. 55 p; oblate, 3-brevico lpate; reticulate , rnuri simplibac ulate. 10. Exine detail, x 720. . I I , 12. Ceiba. I l. no. 26-l , ca. 45 jL ; 12. no. 26-1, ca. 60 p; oblate, 3-brevico lpate; coarsely reticulate. 13- 16. Pseudobombax. 13. no. 26-l, ca. 60 ;•; 14. no. 68, ca. 65 p; 15, 16. no. 63-3; oblate, 3-brevicolpate; Exinesimplibaculat e, reticulate ; 16, x 720.

244

A. S. 13ARTLETT AND E. S. BARGHOORN

I'HYTOGEOG RAI'l-HC HISTO R Y OF T HE ISTHMUS OF PANAMA

PLATE VIII

The presence of Myrica and flex in these samples signilies a cl imatic change at th is time, judging from their present distribu tio ns in Panama (see annotated list of species). Myrica now typically grows at the edges of high, dry win dswept grasslands in Panama, wh ile 1/ex grows only on A neon Hi ll on the Pacific watershed of the Canal Zone, at generally higher elevations in the res t of the Republic, and on San Jose Isla nd. Bot h of these occurrences in the Gat un basin during this interval, fro m 7,300 to 4,200 B. P. suggest that seasonality on the Atlant ic coast may have been more pro: nounced tha n at present. The cl imate nuty, in addition, have been somew hat colder consider ing the present high altitude distribut ion of Myrica in Panama; th is hy pothesis is tenuous, however, and very diffic ult to substantiate. The thesis that climate during part of the interval from 7,300 to 4,200 B.P. was drier and more seasonal may be su pported, however, by evidence presented by Wijmstra and Vander Hammen (1966). In their attempt to determine the origins and history of the Colombian savannas, they discovered possible evidence of early open savanna d uring the period from 5,000~o 4,000 B. P. Open savanna vegetation at this time would antedate general development of th is vegetation in Colum bia, which other pollen evidence indicates did not begin until ca. 3,000 B. P. Pollen of particular in terest from this in terval is that of wild maize, wh ich is between 6230 and 7300 years old. A detailed account of this maize pollen, its age and sig1Jiflcance, has been published (Bartlett et al., 1969).

I ._·

I !o I

245

Vegetation 4,200 B.P. to the present

During the next period, from4,200 B.P. to the time of flooding of the Gatun basi n, the vegetat ion continued to undergo profo und changes. All salt water influence had ceased by 4,200 B.P., and fresh-water swamp vegetation was well-developed . No furthe r evidence of the possible dryness of the preceding period appears. The swamp vegetation of this period appears to have become more open, as tree pollen becomes low in freque ncy. A reas of open water existed, judging from the ab undant pollen of herbaceo us swamp elements. Herbaceous swamp pollen appearing in the peats deposited during this period is

5. 6. Bombacaceae 1, 2. 3. 4.

Cava11illesia platanifo/ia: no. 68, ca. 741•; obla te, 3-brevicolpate ; Exine sculpturing complex;

7- 9.

reticulate, tectate-perforate, and verrucate. Cavanil/esia platamfo/ia: no. 93, ca. 65 Jl; a n abnormal grain, with exine outgrowths at two of the angles of the grain. Cavanillesia hylogeiton-type: no. II , ca. 6011; 3-brevicolpate.

10.

Quararibea: no. 26-1, ca. 631'; triporate, pores with annulus; exine covered with a very coarse reticulu m with very broad, granular muri. Pachira aquatica: no. 62, ca. 90 1•; oblate, 3-brevicolpate; exine reticulate at angles of grain in polar view ; po les covered with papillate projectio ns, which may be arranged in reticulate fashio n. Bombacaceae: no. 100, ca. 100 f.'. This grain is q uite unlike any in our reference collections o f Bombacaceae from Central or South America. 7. Polar view; 8. one of the angles, showing fi lamentous p rojections; 9. exine detail, x 720. Bombacaceae: no. 100, ca. 1 l 5f.'. This type is simila r to Matisia stenopetala in po re structure and exine pattern, but differs in grain size and numbe r of pores.

246

A. S. IJARTLET I AND E. S. IJARGHOO RN

PH YTOGEOG RA PHIC HISTORY OF TH E ISTHM US OF PANAM A

247

PLATE IX

that of Pacourina edufis, Ju.uiaea, Pontcdcriaceae, and Typha. That of Pacourina is of particular interest, as there is apparentl y no record of this genus occurring presently in the Canal Zone. The association of Pacourina and Pofyganum pollen is interestin g, as 1hcsc genera co ntinue to grow together in certain ecological situations to the present day (sec the annotated list of species at the end oft his section). The pollen of Jussiaea was not identifiable at t he specific level. However, small seeds found in the same sample were identical to these of modern Jussiaea natans, indicating that the Panama species, li ke J . ;wratrs, was undoubted ly a floa ting aquatic. Seeds of non-aquatic species of Jussiaea were fo und to be quite different fro m those .of J. natatrs. Typlra is also an aq uatic, growing presently in abundance abou t the shores of Barra Colorado Island and Gatun La ke. Pollen of the Cyperaceae increases greatly in abundance during this peri od, as does that of thc G ramineae. Tree pollen co ncurrentl y decreases greatly in abu ndance. Agricu lture was undoubtedly developed in the vicinity during this period, as shown by the presence of maize and M anifrot escu/enta pollen, charcoal fragments, and high percentages of pollen of Graminea e and Compositae. The great iricrease in herbaceous pollen is therefore undoubtedly due to clea ri ng by man (Bartlett et al., 1969). During the later part of this period, nearly all tree pollen disappears, even that of the "weed trees". The role of the Cyperaceae in this vegetation is not completely clear, as genera cannot be differentiated on the basis or pollen. Cyperaceac now growing in the area are principall y forms growing in marshes or in clearings. The abundance of the foss il grains may therefo re indicate either ex tensive development of sedges as a component of the swamp vegetation, or the innuence of man's deforestation or the land. The climat ic significance of nuctuatio ns of any componen t of this vegetation cannot be resolved, as man 's disturbing influence has undoubtedly greatly obscured the natural co urse of vegetational development in the area.

Ochroma: no. 26-1, ca. 90 I'; polar view of abnorma l 4-brevicolpate grain ; exine reticulate, m uri simpli- to duplibaculate; lumina contain one to several granules. 6. Gyranthera darienensis-lype: no. 9, ca. 100 p.; triporate, gemmate. Sterculiace ae 7. Buellneria: no. 26-J, ca. 25 1â&#x20AC;˘; triporate; pores protruding ; exine reticulate. Dilleniaceae 8, 9. Tetracera: no. 24-2, ca. 22 fl. 8. High focus; 9. section. Spheroidal ; number of apertu res unclear; retipilate. Och naceae 10- 13. Ouratea guatemalensis. 10, Jl : no. 4,ca. 281â&#x20AC;˘; equator ial view, highand mid-focus. 12. no 62, ca. 25 p.; oblique view; 13. no. 4, ca. 25~-t. This view shows endexine characteris tically irregularly t hickened in interio r of grain. 4, 5.

Bombacac eae

Ochroma: no. 100, ca. II 0 p.; polar view; oblate, 3-brevicolp ate; exine reticulate, m uri simpli-

2. 3.

Ochroma sp?: no. 100, ca. 105 p.. T his pollen grain is very similar to both m odern and fossil Ochroma grains, except in the thicker exine and somewhat coarser exine elements.

to d uplibaculate.

focus; 3. mid-focus.

2. High

248

A . S. BARTLETT AN D E. S. BARG J-IOORN PLAT E X

PHYTOGEOG RA PHIC HISTO RY OF TH E ISTHMUS OF PANAMA

Annota ted list of species identified as _pollen in Pa na ma sediments

,... "" ' • ct

•

249

Fl. C. R. = Flora of Costa Rica (Sta ndley, 193?/1 938) Fl. C.Z. = Flora of the Panama Ca nal Zone (Stand ley, !928) Fl. B.C.!. = Flora of Barro Colorado Island (Stand ley, 1933) Bo t. S.J.!. = Botany of San Jose Isla nd (Jo hnston, 1949) Other references are listed as usual.

Monocotyledqnae Antlwrium Scho tt. Araceac The ge nus is a large one in Cent ral America , a nd includes mai nly epi phytes, vines, and ma rsh plan ts. It is abu ndantly represented in the Canal Zone.

Lecythidaccae 3.

Couroupita: no. 100, ca. 70,u ; tetrad, made up of prolate grains ; single grains have a ls o been found. Rhizophoraccae

4, 5. 6.

Rhizophora: no. 100, ca. 22p. 4. High foc us; 5. section. Note the long col~i transversalcs. CMsipourea: no. 26, ca. 19 I'; tricolpora te; psilate to scabratc. ·

Combretum: no. 80, ca. 33 I'; tricolporate, psi la te; weakly developed colpoid streaks present

Combretaccae in intercolpal areas. Couomrptt.l"-typc; no. 70, ca. l 81r; heterocolpatc, psilatc. Myrtaceae I 0. Myrtaccac: no. 123, ca. 34 I'; obla te; syncolpate on bo th hemispheres. Melas tomataceae I I, 12. Melastomataccae : no. 26-1, ca . 25!' ; tricolpo rate, hctcrocolpate ; psilate. Ericaceae 13. Ericaceac: no. 123, ca. 25 f1 ; psilate tetrad. O nagraccae 14. Jussiaea: no. 79, ca . 80 ,u ; o blate, tri po rate ; ectexine loosely attached, wrinkled in places ; trilete scar visible on some grains. This type of pollen occurs in tetrads also. Symplocaceae 15. Symplocos: no. 100, ca. 55/<; tricolporate, co lpi very short; aperture structure characteristic a nd d istinctive; psilate. A pocynaceae 16. Rauwolfia: no. 100, ca. 53/<; tricolporate; psila te; pores characteristically thickened. 17. Tabemaemo111a11a: no. 26, ca. 45 p; colpi transversales or syncolpus transversalis present ; costae transversales also pronounced. Boraginaceae 18. Malouetia: no . 65, ca. 30p ; two to fou r pores, in variable positions; annulus present; endexine irregularly thickened in interior of grain. 19. Cordia a/liodora: no. 24-2, ca. 32p; tricolpora te, spinuliferous. 20. Toumefortia !rirsutissima-type : no. 26-1, ca. 28 t<; gemmate, n umber of apertures not clear. Yer benaceae 21-23. A vicennia: 21, 22. no. 97, ca. 35p,; high and mid-focus, respectively. 23. obliq ue view, no. 97. Lentibulariaceae 24. Utricularia: no. 79, ca . 40 I'; oblique vie w ; stephanocolpor(oid?)atc. 8, 9.

2•.

" ·: : ' l .

,. 'I

i ' I ____ I Guttiferae I.

Symplronia: no. 68, ca . 130 tt ; stephanoporate; exine very thick.

Lafoensia punicifolia: no. 68, ca. 40 p,; tricolpo ra te. Three extra colpoid streaks are often

Lythraceae apparent in the intercolpal areas; a granular ectexino us hood covers the pores.

250

t\. S. BARTL ETT AND E. S. llARGH OORN

PII YTOGEOGR APHI C HISTO RY OF THE ISTHMUS OF PANA MA

!'LATE X I

25 1

Catopsis 11/0rreuiaua-type Bromeliaceae Several species of Catopsis occur in the Canal Zone. All those mentioned by Standley (Fl. C.Z.; Fl. B.C. f.) arc small epiphytes. Zea mays L. Cultivated in Panama for both seed and forage.

Gram incac

Other Gramincae Occur abundantly tn more recent sed iment s. They probably represent vegetation · disturbed by man.

Cyperaceae Pollen abundant in the cores in the zone above that of abundant Rlrizoplrora. Many genera are com mon about the zone in marshes and cleared areas, occurri ng also in the savannas of the Pacific slope.

Cryosophila Palmae Several species occur in Panama. C. warscewiczii (Wend!.) Bartlett is frequent in the forest of Barro Colorado Island and of occasional occurrence in dense wet forests of the Atlantic stope (Fl. C.Z.; Ft. B.C.!. sub Acantlrorrhiza ll'arsceu'iczii Wend!.). Their dis-tri bution in Panama is poorly known (Bailey, 1943). ~ lriartea Ruiz and Pav. Pal mae According to Bailey ( 1943), approximately half a dozen species of this palm occu r in South America. Only one species, I. corneto (Karst.) Wendt., is listed as occurring in - Panama, where it grows in mixed hardwood forests in the hills of Darien Province bet ween I,200 and I,500 m. Another species, I. gigan/ea Wend!. ex Burrel, occurs in the vicini ty of Golfo Dulce and other locations in Costa R ica, at elevations of about - 800 to 900 m. Allen (1956) reports that this stilt-palm occurs in the Golfo Dulce area in nearly pure stands of as much as several acres in extent, in sma ll sheltered coves in the hilts. Standley (Ft. C.Z.; Ft. B.C. f.) reported the occurrence of IriOJ·tea exorrhiza Mart. on Sarro Colorado Island and the Zone. Bailey (1933) in his account of Panama palms, re-identified these palms as Socratea durissima, an identification accepted by Standley in his Flora of Bano Colorado Island ( 1933). The stilt palm formerly known as lriOJ·tea exorrhiza has since also been referred to the genus Socratea. This palm, S. exorrhiza Wendt., is a wide-ranging tree extend ing throughout the Amazon drainage. Dr. H. E. Moore has noted that the Panama species, S. durissima (Oerst.)

·~ .:j l- 4.

5, 6.

Convolvulaceae

Merremia tuberosa: no. 79, ca. 115 f.l. 2- 4. Exine detail, x 720; pollen pericolpate: 2. high

focus; white round areas represent location of spinules; small black dots represent branched ends of ectexine columellae; 3. mid-focus; 4. exine at low focus, showing bases of columellae. Ipomoea: no. 140; ca. 160 I'·· 6. Section, showing spines; pollen echinate, periporate.

7. 8, 9. 10. II.

Ipomoea: no. 76, ca. 85 t•· An interesting example of differential corrosion of exine layers; apparently only the endexine remains {seep. 219). Maripa: no. 75, ca. 48,u. 9. Exine detail; pericolpate, exine with branched columellae; x 720. Acaothaceae Mendoncia: no. 98, ca. 70 f.l; 5-{;()lporate; exine very thick. Aphelandrasinclail'iana-typc: no. 100, ca. 93 ,u; tricolpate.

ll 252

A. S. BARTL ETT AND E. S. llARGHOORN

PHYTOG EOGRAPHIC HI STORY OF THE ISTHMU S OF PAN AMA

PLATE X II

WenJ I., may prove ultimately to be no more than a fo rm or S. cxorrhiza (personal communication, 19 ~7.) Study or the pollen of several species of Socratea and lriartea has suggested that these two genera may be distinguished on this basis. Invest igated in this study were: ( I ) Iriartea exorrhiza Ma rt. (now Socratea exorrhiza Wend!. ) Pittier 8988, Venezuela ; G ray Herbarium. · {2) S ocratea durissima (Ocrst.) Wend!. Bailey 74, Barro Colorado Island ; Bailey H ortorium. (3) S ocratea exorrhiza Wend!. Moore 9559, Belcm, Para, Brazil ; Bailey H ort ori um . ( 4) Iriartea gigantea Wend!. Moore 6574, Sarapiqui Valley, Costa Rica ; Bailey Horlorium . (5) /riart ea l'entricosa Mart. Britton and Rusby 1734, Bolivia; Gray Herbarium. Of the above, those referred to the genus Socratea (nos. l,2, and 3) possess spinuliferous pollen, while those referred to /ri(IJ·tea (nos.4 and 5) possess clavate pollen. It appears, therefore, that the clavate pollen present in the Gatun basin cores from 35,500 B.P. and from 11,300 B.P. to about 4,200 B.P. is that of Iriartea. Thi s highly distinctive pollen is present in samples old er than a bout 7,300 years in appreciable quantity, comprising as much as 30 % of the pollen sum in one sample (no. 28). From about 7,300 B.P. to 4,200 B.P., only low percentages of this poll en are present. In samples younger than 4,200 B.P., only a single grain has been found, appearing in the modern pollen rain.

~-_ I -~;. - ~~ I

-..

,I ' . : .,

. q_ .

I.~.~

.· l . ! f· 3 .. k. l

15··;:_·

l . _, . .!:~,.

I I

· '•

·a

...... II

~~'l<ii

I j

I -.1

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253

Phytelephas Ruiz and Pav. Palmae These ivory palm s occur in wet forests at the head of Gatun Lake (Fl. C.Z.).

13'C:' .... l

A .j

.~1

Socratea-ty pe Socratea durissima (Oerst.) Wend!'. is frequent in the virgin forests of the Atlantic slope (Fl. C.Z., sub /rim·tea exorrhiza; Fl. B.C. I.). See discussil)n of fri01·tea, above.

Other palms The palms of Central America are, in general, not well represented in herbarium col5.

Chomelia-type: no. 68, ca. 25!•-; tricolporate; exine reticulate, simplibaculate; this type is not

Cosmibuena pa/udicola: no. 26-1, ca. 33 p.; tricolporate ; po re has characteristic Rubiaceous

uncommon in the Rubiaceae. structure; exine psilate, with distinctive endexinous thickenings. Faramea: no. 26-1, ca. 35 f' ; triporate; po re structure distinctive; exine scabrate. Randia sp. 8. No. 9, ca. 60 1'-; tetrad; pori circular. 9. no. I 26, ca. 431'; tetrad; pori circular. Cucurbitaceae 10- 12. Sechium edule-type: no. 100, ca. 150 I'; 6-colporate. II , 12. Exine detail, x 720; II. high focus; 12.Jow focus. Compositae 13. Compositae: no. 79,ca. 22JJ; Ambrosia-type. 14. Pacourina edu/is: no. 79, ca. 53tt ; triporate, fenestrate.

7. 8, 9. Acanthaceae l. 2.

Trichanthera gigantea: no. I 00, ca. 110 1-'; diporate; exine structure complex. Justicia: no. 140, ca. 48 11-; diporate, ornate.

Alibertia: no. 26-1, ca. 35 11-; triporate; exine reticulate, simplibaculate. Borreria: no. 79, ca. 33f-t; stephanocolpate, reticulate.

Rubiaceae

254

A. S. BARTL ETI AN D E. S. DARGIIOOR N

l'I-IYTOG EOG RAI' H IC H ISTORY OF T H E ISTHMUS OF PA NAMA

PLATE XIII

255

lcctions, and arc consequently not well known. Thc. .availablc modern pollen reference collection or this group was insuflkicnt, therefore, to determ ine the identity of the lessdistinctive palm pollen in the Gatun basi n sediments. Lack of adeq uate material for purposes of comparison also preven ted the posi tive identification or the more distinctive Socra/C!a-typc pollen, a type which is not uncommon among the pa lms. Pontede riaceae This fam ily is represented in Panama by three genera, !-le/erantllera, Ponlederia, and Eichlwmia, all of which grow in mud or water about Gatun Lake. Fossil pollen of this family was not differentiat ed at the generic level.

Typlw anguslifolia L. Typhaceae This, the common cattail of tropica l America, is frequent in shallow water on the shores of Galun Island. Dicoryfedonae Apllelandra sincfairiana-type A shrub frequent in wet Atlantic slope forests. "'"## ···.• •, w ·~~·~· ,,

I I

Acanthaccae

Juslicia L. J'n the Canal Zone, several species of these small or large herbs-are common in moist locations in woods, thickets, and along s treams (Fl. C.Z.).

Mendoncia Yell. A coarse, herbaceous vine, M. ref usa Turrill, occurs infr!';.q uently in moist woods of the Canal Zone (Fl. C.Z.). I

Trichanlheragigan/ea( H. B.K.) Humb. a nd Bonpl. A tree common along streams and in wet forests (Fl. C.Z.).

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Y.C-'11~'!;."

10 .

.~ -<<,___...,

Moffugo l'erlicillala L. Aizoaceae This small, weedy annual, common in many parts of t he United States, is the only Central American species. lt is widely d istributed in waste places of both temperate and tropical regions (Fl. C. R.).

I. 2.

3. 4.

Monolete type A. Monolete type B. Monolete type C. Monolete type D.

Acrosrichum.

Fern spores

7, 8.

Hemite/ia ( = Cnemidaria) Danaea-type , h igh focus and section.

Podocmpus: no. 68, ca. 83 J.l·

10.

Corroded fern spore (seep. 219).

Podocarpacea e Fern spore Unidentified 11 , 12. Syncolpate pollen grain, high focus and section. Family is unknown, but this type should be easily identified if it turned up in a modern reference collection.

T 256

A. S. llARTLE TT AND E. S. IJARG HOORN

Alumwntlrera-ty pc Amara nthaccae Generic di Ocrentiat ion of the pollen of th is fam ily was not attempted. Pollen of many genera is virtua lly identical to that o-f man y of the Cheno podiacca c. The Ama ranthaccac of Panama arc mostly weedy plant s, which, accord ing to Stand ley, arc of little importan ce in Pa nama (Fl. C.Z.). Anacard iaceac Altho ugh we included in our reference collectio n pollen of most of the common Anacard iaceae of Panama , most of the fossil pollen which obviously belonged to this fam ily did not match it. T herefore, this pollen was only identified at the fa milial level. Annonaceae As pollen of this family was infreque nt in the core sediments, detai led study of many species was not undertaken. Although a nearly complete collectio n of the Panama nian genera was available, the highly distinctive fossil pollen proved not to be identical to any of them. A more complete collection with better species represen tation would undoubtedly resolve the identity of this fossil type. Mem bers of this famil y are frequent in a variety of habitats in Panama.

Malouetia guatemalensis (M uell. Arg.) Standi. Apocynaceae This, the only Central American species, is a small tree frequent in swampy woods of ~the Atlantic watershed (Fl. C.Z.) Rauwolfia L. Shrubs occasional in thickets of the Pacific slope (Fl. C.Z.). Tabernaemontana L. One species, a small or medium-sized tree, grows on Sarro Colorad o Island. Additional species are known also from the Canal Zone (Fl. C.Z.). flex L. Aquifoli aceae flex does not characteristically grow in the Canal Zone at the present ti me. It is f~und

there apparently only exceptio nally, as it grows there on ly on Ancon Hill (Standley, 1928). The single species fo und there, /. occidentalis Macf., does not appear to grow elsewhere in Panama . Additional species, among them I. guianensis (Aubl.) Kuntze, occur elsewhere in Panama, generall y a t higher elevations. /lex is fo und, fo r example, on the mountains of Chiriqui Province at elevations of 1,800 m, and extends as far east as the hills south of El Valle, where collections have been made at elevations as low as 700-800 m. Collecti ons of /lex have also been made on Bocas Island near Almirante, in Ch iriqui Province. flex occurs also on San Jose Island in the Perlas Archipelago, where it is one of the common trees on the southern half of the island (Bot. S.J.I.). Here, I. guianensis, the only species on the island, grows in forest which has reached a mature phase of development, and is one of t he principal canopy trees. According to Johnsto n (Bot. S. J.I.), "the vegetation would be classed as an

PHYTOGEOG RAPHIC H ISTO RY OF THE ISTHMU S OF PANA MA

257

insular aspect or that dominat ing the dry l ow l and~ or the Pacific slope of Costa Rica and western and middle Panama" (Johnston, 1949, p.5). The majority of the plants growing on the island range, according to Johnston, at low alt itudes in those parts of. the American tropics which have a pronounced wet and dry season, such as southeastern Mex ico and western Central America, Yucatan, Ho nduras, and eastern Guatema la, northern Colomb ia and Venezuela, and part of the West Indies. The climate of the island, which receives an average of fro~n 85 to 99 inches of rai nfall annually, is, according to Johnsto n, quite similar to that of Bal boa on the adjacent mainland. It di ffers, however, in having approximately 30 inches m ore of precipitation annually, and in having, usually, a rainless dry season. Temperature extremes on the isla nd of 19.4 and 32.2Â°C have been recorded, but the average m onthly tem perature varies between 24.4 and 26.6Â°C (J ohnston , 1949). Since te mperatu res are thus very similar to th ose on the adjacent mainlan d, the main differenc e between lh!! cli mate of San Jose Island and that of the adjacent portion of the Canal Zone appea r~ to be the more pronoun ced dry season o n the island. Although there are many factors which CO_!lld govern the distribut ion of I/ex in Panama , the degree of aridity du ring the dry season may rank importantly among them.

Alnus .Betulaceae A single species, A. ferrugin ea H BK., occurs in Panama at high elevation s. In the Ch iriq ui Volcano region, for example, it forms nearly pure stands, or grows together with oaks. fn the 2,400-3,000 m zone, it occ upies about 20% of the forest stand (Nevling, 1960). Isolated occurrences of pollen of this genus throughout the entire stratigra phic colu mn and in the modern pollen rain undoubtedly represen t long-distance transport. Bombacopsis quinata (Jacq.) Dugand Bombacaceae A characteristic tree of deciduous forests, found occasionally also in evergreen forests and thickets, extending along the Pacific coast from N icaragua to Panama , northern Colombia and Venezuela (Robyns, 1964). This species, which grows on Barro Colorado Island, was described by Kenoyer (1929 sub B. fendleri (Seem.) Pittier) as among the pioneers participati ng in the refo restation of clearings. Bombacopsis sessilis (Benth.) Pittier This tree grows in Costa Rica and Panama, growing naturally at the edge of a nd in deciduous forests. In Panama, where it is often planted as a shade tree, it occurs in numerous locations. Cavanillesia Ruiz and Pav. This remarkable tree is not found north of the Canal Zone region, accord ing to Standley (Fl. C.Z.), but extends southwa rd to Peru (Robyns, 1964). It is common about the Zone. Althoug h it is thought by Robyns t o be the only species now occurring in Panama, polle n closely resembli ng that of C. hylogeit011 Urb. was also found in the fossi l record.

258

A. S. BART LETf AND E. S. UARGHOOR N

Ceiba Mil l. A pantropical ge nus, of wh ich mo>1" of the species arc native to tropical America; two species are repor ted from Panama. Ceiba penlamlra ( L.) Gaerln. is a pan tropical tree up to 40 m tall, growi ng chiefly in secondary fo rest, and is often cultivated and naturalized. C. rosea (See m.) K. Schum. grows in Panama on hills and fo rested slopes (Robyns, 19.64). Pollen of th is genus from the Gatun basin sa mples was not difierentiated at the specific level, as pollen of C. rosea was not avai lable for study. Ochroma pyramidale (Cav. ex La m.) Urban Ochroma is a neotropical, monotypic genus, ranging from southern Mexico to Bolivia (Robyns, 1964). K nown commonly as the balsa tree, it is common about the Zone, and is often cultivated. It grows with extreme rapidity, often reaching a heigh t of 16-20 mi n five or six years (Fl. C.Z.). It is a conspicuous member of the pioneers on cleared ground , and is often referred to as a "weed tree".

Pachira aqualica A ubi. This tree ranges from southern Mexico (Vera Cruz, Oaxaca, Chiapas, Yucatan), through Central America to Ecuador, northern Peru, and northern Brazil. Growing always on moist ground, it is typically riparian, occurring along periodically in undated lake shores and river banks (Robyns, 1964). In the Canal Zone, it is particula rl y com mon in swa mps of the Atlantic coast. It is a distinctive plant, for example, in shallow water along the banks of the lower Chagres River (Fl. C.Z.; Johnston, 1956). Pseudobombax septenatum (Jacq.) Dugand This, the only Panamanian species of this neotropical gen us, ranges from Nicaragua to Panama, Colombia, Venezuela, Brazil, and Peru . It is often planted and occurs on forested hills, in pastures, and along roads, usually on sandy soil (Robyns, 1964). Quararibea Aubl. A neotropical genus of trees or shrubs comprising about 75 species, of which six are found in Panama (Robyns, 1964). Other Bombacacea e Other grains belonging to this family were found wh ich did not match any of those in our collection. Among these was a three-pored type which was similar to Malisia stenopeta/a Standi. (Klug 2972, Peru) in exine structure and pore details, but not in grain size and number of pores. An additional interesting type found was pollen closely matching that of Gyranthera darienensis Pitt. ; this grain was identified as G. darienensis-type, as there may be other members of this family having this type of grain which are not represented in our reference collection.

Cordia alliodora (Ruiz and Pav.) Roem. and Schult. Boraginaceae A common tree in the Canal Zone, and one of the most abundant trees in Central

PHYTOGEOG RA PHIC 1-J ISTOR Y OF T H E ISTHM US OF PA NAMA

259

America. It is one of the prominent s pecies in reforestati on of cleari ngs on Barro Colorado Island (Kenoyer, 1929).

Toumeforlia hirsulissima- type The Tourncfortias arc usually scanclcnt shn1 bs. T. hirsutissima L. is occasional on the Atlantic slope, and occurs on Barro Colorado fsland. Bursera Jacq. ex L. Bu rseraccae Bursera simaruba (L.) Sarg. is a common tree or'this region. The species ranges from Florida a nd Mexico to northern South America. Johnsto n (1956) men tions it as a tree freqLICntly found in th in-soil environmen ts, as for example on the limestone outcrops of the Fort Sherman-Ga tun road in the Canal Zone. Chenopod iaceae Pollen of the Chenopodiaceae is very similar to that of many of the Amaranthaceae, and genera may not be distinguished on the basis of pollen. Pollen of this type, although it may belong to ei ther of these fam ilies, have been designated in the pollen diagrams as "Chenopod iaceae". This p ollen is not common in the Gatun basin sediments.

Hedyosmum Sw. Chloranthaceae The genus ranges from Mexico south to Peru, Bolivia, and Brazil in the New World (Nevling, 1960). Its distribution in Panama, as indicated by herbarium specimens, is from altitudes of about 100m to more than 1000 m. As the gen us apparently does not grow in the Canal Zone today, the scattered occurrences of its pollen throughout the length of the Gatun basin deep cores probably represent long-distance transport. Combretum L. Coarse, high-climbing woody vines (Fl. C.Z.).

Combretaceae

Conocarpus erecta L. One of the characteristic species of mangrove swamps, this monotypic genus is widely distri buted in tropical America and occurs also on the coast of West Africa (Fl. C.Z.). On San Jose Island, it is frequent on the drier margins of mangrove swamps, occurring also on sand and shingle beaches at sites flooded only occasionally by storms and the highest tides (Bot. S.J.I.). Pollen from the sediments is designated as Conocarpus:type as it is not distinguishable with absolute certainty from that of some of the Melastomataceae. The difference between the pollen of Conocarpus and that of the Melastome genera is mainly one of degree, as it is distinguishe d from them on the basis of a slightly thicker exine and a somewhat smaller pore. In addition, it becomes browner upon acetolysis than does that of t he Melastomes. Pacourina edulis A ubi. Compositae This species, to the writers' lmowledge, h as not been noted as growing in Panama at

260

A. S. BARTLETI AND E. S. BARGHOORN

the present time. Herbarium material is scant in the Gray Herbarium and the 1\rnold Arboretu m Herbarium of Harvard Universi ty, compri sing a total of only len specime ns (one from Surinam, one Colombia, two Pa raguay, one Guatemala, and th ree West Indies). Ecological notes on one sheet provide the informat ion that the species usually grows together with Po/ygonum acumiua/um. Th is is interesting, as sediment samples containing this distinctive Pacouriua pollen contain also the pollen of Polygomnn. The species may grow in several f~et of water, and occurs in Surinam as an occasional in fresh to mesoha linous swamps (Lindeman, 1953). Ipomoea L. Corwolv ulaceae A large genus in Central America, with many representatives known rrom Pana ma. [t occupies a vari~ty of habitats, and includes several crop species, notably / . batatasÂˇ (L.) Lam. and / . aqualica Forsk. Maripa Aubl. Large woody vines. One species, M. panameusis, occurs on Barro Colorado Island. Merremia tuberosa (L.) Rendle The common yellow morn ing-glory (Fl. C.Z. , sub Operculiua luberosa (L.) Meisn.). The pollen of this species is not at all similar to that of any of the other Central American species in the Gray Herbarium and the Arnold Arboretum collectioi1s. Sechiwn edu/e-type Cucurbitaceae A large herbaceo us vine with edible fr uits known as "chayote" in Panama. Tetracera l'olubi/is-type Dilleniaceae These plants are woody vines. Several species are common about the Zone (Fl. C.Z.). T he fossil pollen corresponds closely to both that of T. l'O!ubifis L. and T. fagifo/ia Willd. ex Schlecht. , both of which are frequent in thickets and forests (Bot. S.J.J.). Ericaceae Members of this family apparently do not occur in the Canal Zone at the present time, and grow at higher elevations in the rest of Panama. A search of the entire fam ily in the Arnold Arboretum Herbarium, Gray Herbarium, and the National Herbarium revealed only two collections of material from elevations as low as 500 m. Both specimens, one of Vaccinium dissimile, the other of Anthopterus wardii, were from southern Darien at elevations of 500 m. Other collections of material from below 1000 m originated in the Elle Valle de An tori. area. Two epiphytic shrubs, Cal'endishia /ongiflora and an ~m id enti fied species of the same genus, grew at elevations of 650700 m, and 600 m, respectively. Long-distance transport of the pollen of members of this family is unlikely, as they are insect-pollinated and do not produce pollen profusely. Therefore, fossil grains in the Panama deep cores must represent a fo rmer extension of range of this family. Presence of these grains in late-glacial and early postglacial samples indicates, therefore, a vertical displacement of members of this family of at least 500 m.

PHYTOGEOG RAPHIC HISTOR Y OF T HE ISTH MUS OF PANAMA

261

Acalyplw_L. Euphorbiaceae Nu merous species occur in Panama. These include he rbaceous, shrubby, or arborescent types, weeds and co mmon forest shrubs. Alclwmea Swartz Several species of this gen us occur in Panama. Alchornea costaricensis Pax and Ho!Tm., a small tree, is frequen t on the Atlantic slope. Crotonoid Euphorbiaceae This pollen type is com mon to a large number or gene ra in th is family, among them Croton and Codiaeum. While differences in size and other pollen characters do exist a mong members having this pollen type, ma ny genera are doubtfully distingui shable on the basis of the pollen, at least without exhaustive study of modern species. Clycydendron amazonicum Duckc Not presently found in Panama. These arc large trees, 20-30 rn tall, growing m primary Brazilian forest. Hieronyma Allem. Forest trees. Hieronyma a/chomeoides Allem. is a frequent tree in the forests of Panama. Hura crepilans L. A fo rest tree which may reach large proporti ons. It is frequent in Panama (Fl. C.Z.; Fl. B.C.l.). Mabea occidenJa/is Benth. A common shrub or small tree. Manilwt Adans. Manilwt escu!ema Crantz is cultivated in Panama for its ed ible roots. This plant, known as "cassava" a nd "yuca", also occurs wild, as an escape from cultivation (Fl. C.Z.). Pilyllanthus L. _ Th is genus, which includes trees, shrubs, and herbs, is a large one in Panama, where its representatives occur in a variety of habitats. The pollen of one species, P. acuminatus Yah!, is distinct from that of the other species, according to Punt (1 962). This species, pollen of which occurs in the Gatun basin sedi ments, is a common shrub or small tree of the Canal Zone (Fl. C.Z.). Sapium Jacq. Shrubs or trees, several species of which occur in the Canal Zone (Fl. C.Z.). Symphonia gfobulifera L.f. G uttiferae This, the only North American species, is a tall tree occupying a variety of habitats. In Surinam, it is reported as abundant in marsh forest where it withstands permanent

262

A. S. BARTLETT AND E. S. BA RG BOORN

inund ation, and as rare in rain fo rest (Li ndeman, 1953). Jn Panama, Stand ley characterizes it as occu rring in the Atlantic fores ts (Fl. C.Z.), while in Costa Rica, it grows in the fo rests a t alli tucles up to 2,400 m. (Fl. C. R.). In Costa Rica, it is also reported by Allen (1956) as occurri ng in ex tensive, nemly pure stands in a reas o f fres h-wa ter swamp.

A1uczma Adans. Large herbaceous or woody vines.

P.rioria copaifera G riseb. T his tree is ~ n e of the com mo n species in fo rests o f the Atlantic watershed, growing best in areas wh ich are periodically flooded by fresh water (Fl. C.Z. ; Jo hnston , 1956).

Couro11pita A ubi.

Bauhinia emarginata Mill.

Legumi nosae

A tree, common in the Canal Zone.

Ca/liandra Benth. A n umber of species occur in Panama; t hese trees and shrubs grow today on Barro Colorado Island.

Canai'Glia H.B.K . The Canavalias are large herbaceous or suffrutescen t vines. T wo species, C. bicarinata Stand i. and C. panamensis Piper. are frequent o n t he Pacific watershed, while a third, C. rosea (Sw.) DC., is frequent on beaches (Fl. C.Z.).

Copaifera J acq . T rees, occasional about the zone (Fl. C.Z.). Drepanocarpus-typc Drepanocarpus lunatus (L. f.) Meyer is an erect or scandent, spiny shr ub occur ring on the Atlantic coast (Fl. C.Z.). In Surinam, it is very common and occurs in nearly pure stands in swamps and along rivers (Lindeman, 1953). Erythrina L. Shr ubs or trees. Erythrina g/auca, one of t he abundant trees of Panama, prefers swampy gro und. It for ms dense, nearly pure sta nds in swamps near the P acific coast (Fl. C.Z. ). Leucaena multicapitu/a A freq uent tree of the Canal Zone.

263

Mimosoideae This subfamily is very abundantly represented in Panama. Fossil pollen designated simply as that of Mimosoiclcae is distinctive as belonging to this group, but is not dist inguishable a l a gener ic level at this time. Members of t his group ident ified to gen us are g iven sepa rately in the pollen diagrams (e.g., Calliandra).

1/ippocratea volubilis L. Hippocrateac5;:ae A large woody vine, occu rring in the fo rests o f Panama. It is frequent 6n Barra Colorado Island (Fl. C.Z.; Fl. B.C.J .). Lecythidaceae Med ium to gigan tic trees. T heir scarcity in Central ~me ri ca, and consequently in herbaria, has prevented the determ ination of the number of species growing in Pana ma. Pollen of one species, C. guianensis A u bi. , the cannon-ball tree, has p roved to be very distinctive, consisting of both permanent tetrahedral tet rads con taining prolate (!) grains, and single grains. T hese two types, according to Jacques (1 965), occur in the same ftowe r,-bu t not in one anther. It remains to be seen whether the other species also possess such pollen. Both types o f this pollen occur as fossils in the Pana ma sediments.

PB YT OGEOGRA PI II C H ISTORY OF THE ISTHMUS OF PANAMA

Pterocarpus officina/is-type

T his tree, frequent on the A tlantic watershed, thrives in localities subject to intermittent flooding (Johnston, 1956).

IÂˇ'

A tree, occurring abundantly in forests of t he C hagres watershed.

S IVartzia panamensis-type Utricrrlaria L. Bot h aquatic and terrestrial forms occur in Panama. Oryctanthus cordifolius (Pres!) Urban A parasite, fo rming large masses upon trees (Fl. C.Z.). Lafoensia punicifolia D C. A slender t ree, frequent in t he fo rests o f the Pacific slope (Fl. C.Z.).

Lentibu lariaceae Lorant haceae

Lythraceae

Byrsonima crassifolia ( L.) HBK.

Malpighiaceae on brushy hillsides. It often fo rm s extensive groves at low altit udes a long the Pacific slope of Central America (Fl. C.Z.).

A shrub or small t ree, common in fields and

Other Malpighiaceae Pollen is not d iffere ntiable at t he generic level. Panamanian genera include t rees, sh rubs, and woody vines which oc~upy a variety o f habitats (Fl. C.Z.). Malvaceae Pollen of this family was identified only at the famil ial level. Melastomatace ae The pollen o f most genera found in Panama is very similar, and was not d ifferen tiated . The p recise significance of the remarkably high percentages of this pollen fo und in some of the deep core samples cannot be determined , theref ore. H owever, some of the members of this fa mily are very abundant in Panama today. One genus fo und o n Barra Colo rado Island, Miconia, is the most abundant plant at the edge of the lake in some areas.

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A. S. 131\RTLETf AND E. S. 13ARG HOOR N

PH YTOGEOG RA PII IC HISTORY OF THE TSTHM US OF PANAMA

Mcnispermaccac

P iperaceae Pollen of this fam ily.was not dinerenliatcd at the gener ic level. Several genera occur in Panama. One, the genus Piper, for ms one o f the la rgest groups o f Central American p lan ts (Fl. C.Z.). Members of' this family include trees, sh ru bs and herbs.

Small woody or nearly herbaceo us vines (Fl. C.Z.). Moraceae See Urticales.

Myrica L. Myricaccae A single species, M. mexicana Hum b. a nd Bon pl., grows in Panama, where it is fou nd along the margins of residua l patches of fo rest in high dry windswept grasslands (Ncvling, 1960). ll apparen tly does not grow below 600-800 m, and is not found in the Ca nal Zone at p resent.

Podo stemonaceae Two genera occur in Pana ma. Both arc s m all her bs, which grow submerged in run n ing water, attached to stones.

Cocco/oba-lype Po lygonaceae T rees and shrubs, occupying a variety or habitats th roughout the Zone. F ossil p ollen of the core samples was very similar to that also of Muelr/enbeckia tamnifolia (H BK.) Meissn. Positive identifica tion cou ld not be made, therefore, without a more com plete collection o f Coccoloba pollen.

Compsoneura spruce! (A. DC.) War b. Myristicaceae This, the only Central American species, is a slender tree, occasional in the forests of P anam a. Dia/yantlrera Warb. Trees, o f occasional occurrence in the hillside fores ts of Panama. According to StandIcy (Fl. C.R.), they occur in Costa R ica at altitudes of less thaJt 670 m. Virola Aubl. V. sebifera A ubi. is one of the common mature forest trees of Barro Colorado Island ( Kenoyer, 1929, sub irianthem panamensis Warb.). T his a nd other species are common trees of lowland and h illside forests of Panama. Two distinct types of pollen were fou nd in the sed iments, one corresponding to V.nobilis A.C. Smith, V. kosclmyi Warb., and V. guatema/ensis(Hemsl. ) Warb. This type of pollen was designated Virola type I. The other type, correspo nding to V. sebifera Aubl. and V. e/ongata Warb., was designated Virola type H.

OwÂˇatea guatema/ensi~ Engler Ochnaceae A slender shrub or small tree, common inside shaded forests (Bot. S.J.T.). Liriosma Poepp. and End !. Olac;iceae This genus does not grow in Panama at present. T he foss il pollen matched closely t hat of Liriosma adhaerens Sp ruce and L. macrophylla Benth., both of wh ich are tropical South American trees and shrubs. Jussiaea L.

Onagraceae S mall or large herbs, sometimes small shrubs, usually g rowing in wet soil. Many sp ecies a re common weeds. T he fossil Jussiaea pollen did n ot match any of the species of this genus in the reference collection exactly. H owever, small seed s found floating in one of the sediÂˇ ment samples (no. 79) containing this pollen are nearly identical to those of Jussiaea natans H BK., which is a common floating plant of the Chagres River and Gatun Lake.

265

Polygomm1 L.

Polygonaccae Five species of the sec! ion Persicaria occur in Panama, all of which have paludal or aquatic forms (D uke, 1960). One species, P. punctatwn, is rather common in shallow water about G atun Lake (Fl. C.Z.). ~

Portulaca oleracea L. A herbaceous weed, common in the Cana l Zone.

Po rtulacaceae

Cassipourea A ubi. Rhizophoraceae Trees or shrubs. One species, C. elliptica Po ir., occurs frequently in the Ca nal Zone, and often grows in mangrove swamps (Fl. C.Z.). Rhizophora L. Th is is the dom inant genus in coastal m angrove swamps of the American tro pics. Rhizophora grows best on deeply flooded lan d, generally in the zone between extreme low tide and mean tide level (Johnston, 1956). It sometimes for ms extensive swamps in sheltered place5 along the coast, and may ex tend inland along rivers to the limit of tidal influence. Licania arborea Seem. Rosaceae A small or medium-sized tree, occurring locally in the dry fo rests of the Pacific watershed (Fl. C.Z.). Alibertia edulis (L. Rich .) A. Rich. Rubiaceae This, the only North American species, is very comm o n in the moist forests of Pa nama (Fl. C.Z.). Borreria Meyer Annual or perennial herbs, which are usually weeds of waste or cultivated gro und (Fl. C.R .).

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A. S. BARTLETT AND E. S. BARG iiOORN

C/rome/ia-type Pollen of this type is not dist inguishable from that of a number of other genera of this family. Cosmibuena pa/udico/a Standi. A small tree, found on Barro Colorado Island. Faramea Aubl. Shrubs or small trees. Several species occur on Barro Colo rado fsland (Fl. B.C.I.). Randia L. A num ber of Randias occur in the Canal Zone. Two types of pollen belonging to these shrubs were found in the sediments. Zanthoxylum L. Rutaceae A number of species occur in Panama, and at least three are represented by pollen in both the deep cores and in the modern pollen rain. One common species represented in the sediments is that of Z. setulosum, an endemic species. A second type which was not identifiable at the specific level was designated Zanthoxylum sp. in the pollen diagrams. A third type certainly referable to this gen us occu rs in both the deep cores and the modern pollen rain; it is here designated as Zamhoxylum panamense? Z. panamense P. Wilson, an endemic species, is one of the most common trees on Barro Colorado Island, and is common also in the rest of the Zone (Fl. C.Z.; Kenoyer, 1929). T herefore, as the fossi l pollen does not appear to be that of any of the other Panamanian species, and as it occurs in very high frequency in the modern pollen rain around Barro Colorad o fsland , it may be that of Z. panamense. As pollen of this species has unfortunately not been available for study, the pollen is referred to as Z. panamense? in the pollen diagrams. Cardiospermum L. Sapindaceae Herbaceous vines. One species, which may be somewhat woody, is common in thickets (Fl. C.Z.). Cupania L. Shrubs or trees. Several species occur on Barro Colorado Island. Paullinea L. A number of species of Paullinea occur in Panama. These are large woody vines (Fl. C.Z.). Sap indus Tourn. ex L. The only Central American species is Sapindus saponaria, a widely distributed tree. Hydrangea L. Saxifragaceae One species, H. panamensis Standi., occurs on Barro Colorado Island as a small; creeping epiphyte (Fl. B.C.I.).

PIWTOGEOGRAPi i l C lilSTORY OF TH E IST HMUS OF PANAMA

267

Quassia amara L. Simaroubaceae This, the only Cen tral American species, is com mon in the forests ofthe Atlantic slope. It is a slender shrub or small tree (Fl. C.Z.). Buettneria aculeata Jacq. Sterculiaceae A variable species of tropical Central America and northern South America. It is a scande~t shrub or Iiana, and occurs usu ally in wet habitats, often in seconi:! growth (Robyns, 1964). It is common in the Canal Zone. Symplocos Jacq. Symplocaceae A number of species now grow in Panama. None are found in the Canal Zone, as these plants appa rently grow at elevations of more than 1000 m. This distribu tion pattern is demonstrated by altitude notat ions on herbarium specimens from the Gray Herbari um, the Arnold Arboretum Herbarium, and the National Herbarium. Apeiba membranacea Spruce ex Benth. Tiliaceae A species frequent in the forests of the Atlantic slope. Thi~ tree ranges from Costa Rica and Panama to western South America, from Colombia to Bolivia (Robyns, 1964). The species is found on Barro Colorado Island (Fl. B.C.T., sub A. aspera A ubi.). Apeiba tibourbou A ubi. This species, found throughout tropical Central and South America, is one of the common trees of the Zone, where it grows in swamps and on dry hillsides. Robyns (1964) gives its distribution as in dry.fores ts and thickets, in open sunlight, at the edge of savannas, and along roads. Luehea seemannii Tr. and Planch. This tree is very common in the forests of the Canal Zone, and one of the common trees of Barro Colorado Island. It is dispersed throughout tropical Central America and Colombia, where it occurs in wet lowland forests (Fl. C.Z.; Robyns, 1964). Urticales Pollen designated as that of the Urticales is of three families, _the Ulmaceae, Moraceae, and Urticaceae. T he pollen of many genera of these three fam ilies is very similar., and cannot be distinguished. Pollen of Ficus and Cecropia of the Moraceae and Trema of the Ulmaceae could be ident ified in sediments containing well-preserved pollen, but pollen of this order could not be differentiated at the generic or even familial level when found in poor condition. Many members of this order are very common about the Zone, and are important components of forests, and, in par ticular, of cleared areas. Ficus is very common everywhere about tl1e zone, as is Cecropia. Both of these genera, in addition to Trerna, are among the most important pioneer trees taking part in the reforestation of cleared land.

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A. S. DARTLETI AND E. S. llA RG HOORN

PHYTOG EOG RA I' HIC HISTORY OF TH E ISTHM US OF PANAMA

A t•icennia L. Verbenaceae A1•icennia nit ida, the black mangrove, is a commo n tree of ma ngrove swamps, where

" relative" sea-level change, which is any a ltitudin al a lteration of the relationship of la nd to sea in a pa rticular area. Altho ugh c uslat tc sea-level ch~nge undoubted ly accompanied each of the glacial stages of t he Pleistocene, sufficient evidence to allow ap proximate measurement of the magnit ude of each lowering and the rate of subsequent rise is available in detail only from the last major cycle of change- the Wisconsin.

it is most ab undant in zones flooded only at mean at~d high tides. As t hese trees are insect po llina ted, they may be under-represented in the foss il record .

'! -.1

Cissus L. Woody vines, of freq uent occur~ence in Pa nama (Fl. C.Z.).

Vitaceae

Vochysia Aubl. mut.· P oir.

I; I

Large forest t rees, of occasional occurrence about the Zone (Fl. C.Z.).

Other groups Podocarpus L 'Her.

Podocarpaceae A shrub or tree, growing in the mountains of Panama. Pollen of this gen us fo und at most levels in the deep cores, never a t high freque ncy, can undoubtedly be attributed to long-distance transport from the mountai ns.

Se!aginella Beau v. Selaginellaceae Se!agineffa co mmonly grows o n forest floo rs, and is abundant on Barro Colorado Island. Fern spores It was fou nd impossible to identify these without first acquiring a good representative collection of modern fern spores. For this reason, these are classified here only as belonging to o ne of four morphological classes, with the exceptio n of spore> of Acrosticlwm a nd Hemitelia (Cnemidaria) . Two species of Acrostic/rum occur in Panama, one of which, A. aureum, is characteristically fou nd in_mangrove swamps. The other species, A. danaeifolium, thrives best at the inland li mit of tidal infl uence, where water is o nly weakly saline,

Hemitelia ( = Cnemidaria Prest) Cyatheaceae Highly distinctive spores, occasionally fo und in the Gatun basin sediments. T his tree fern is an occasional about the Zone, occurring on Barro Colorad o Island. Sea-level change-the literature

Introduction One of the maj o r geologic conseq uences of the world-wide climatic changes associated wit h the Pleistocene Epoch was that of profound fluctuations in sea level. These fluctuat ions, which are world-wide and affected uniformly the sea as a whole, are termed "eustatic" sea-level change (Suess, 1906), which distingu ishes them from

269

Early work G lacial control of world-wide sea level was recognized in Europe as ea rly as 1841 by Cha rles MacLaren (1 841) who realized that sea-level changes wo uld logically acco mpany the continental glaciation proposed by Louis Agassiz in his paper Etudes sur Jes Glaciers (published in 1840) presented before the Helvetic Society in Lucerne in 1837. An early American contributor, C harles Whittlesey (1868), deduced on the basis of estimates of fo rmer thickness and extent of glaciers that sea level during the ice age could have been lowered by as much as 300--400 ft., a remarkably acc urate calculation for that ti me. Other early estimates range from ca. 1200 ft. (Shaler, 1875) to 490 ft. (Von D rygalsk i, 1887) with Penck (1 882) estimating a loweri ng of ca. 2 18 ft. d ue to ice locked in Pleistocene glaciers of the Nort hern Hemisphere alone. Early work on fo rm\!r sea levels was concentrated in good part on evidence in the fo rm of ancient shore lines. Two noteworthy early contributors, according to Zeuner (1945) were Deperet ( 1906) and De Lamothe (19 11), who studied forme r shore lines of the French Mediterranean coast and Algeria, respectively. De Lamothe recognized four cycles of sea lowering and raising, but apparently never connected them with the waxing and waning of ice sheets (note in D aly, 1934). D aly, who became interested in glacial control of sea level in connection with the problem of the origin of coral reefs and atolls especially (Daly, 1910, 1915), subsequently studied sea-level change (1920, 1925) and reviewed t he problem in 1934 (Daly, 1934). I n his review, he included an account of factors which render the correct interpretation of fo rmer sea levels difficult, placing special e.mphasis on unequal deformation of coastlines d ue to transfer of water, effect of gravitational pull of the ice mass on the ocean in the Northern Hemisphere, and on deformation of the ocean basins by removal and subsequent return of vast quantities of water. Extensive research has been done since then on evidence of former sea levels below the ocean's p resent surface as well as on raised features. Very important advances in knowledge about former sea levels have resulted from the development of radiocarbon dating for more recent events, and of t he 2 3llTh/ 234 U method of dating older marine carbonates.

Problems in interpretation offormer sea level Interpretation of t he course of rising sea l evel accompanying the waning of glaciers

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A. S. BARTLEIT AN D E. S. BARGHOOR N

after the last glacial max imum is complicated by a number of factors other t han glacial control which cause changes in the rela tive positions of land and sea. T hese factors have been discussed by a number of individuals (Daly, 1934; Zcuner, 1945; Fairbridge, 196 1a; Jelgersma, 1961; Bloom, 1967, and others), and have been divided into three groups by Jelgersma. T hese are movements of sea level, tectonic movements, and compaction of sed iments. The first includes m~nor causes of change of level such as the deformation of ocean basins (Jelgersma, 1961; Fairbriclge, 1961a; Bloom, 1967), additio n of water from t he eart h's interior (Daly, 1934; Kuenen, 1954j Jelgcrsma, 1961), changes in water vo lume under temperature cont rol (Jelgersma, 1961; Fairbridge, 1961 a) and the addition of sediments to ocean basins (Fa irbridge, 196Ia). Bloom has stressed that the Âˇ isostatic adjustment of the ocean floor due to removal or additio n of water must also be considered. T ectonic movements are a particularly important factor in areas undergoing isostatic uplift after deglaciation, and must also be considered in sea-level studies in mobile belts and areas undergoing extensive downwarpin g, such as the Mississippi delta, where the interglacial surface on which sedi ment was deposited by the latest rise of sea level has subsided as much as 500 ft. Bloom (1967) has pointed out that coastal regions -will also undergo downwarping due to the increasing water load added by rising sea level. The degree of down warping depends on ma ny variab les, among which he includes the depth of water offshore, the rate and magnitude of sea-level rise, the seafloor slope nearby, and the map configuratio n of the shoreline. The degree of importance of the role of sediment compaction varies with the type of sediment. Sand has a very low compressibility, so low that Terzaghi and Peck (1948) felt that "in connection with practical problems (in relation to building) the compressibility of confined strata of sand can usually be disregarded " (p.61). The compression of sand consists mainly in shifting of grains to decrease the size of the void spaces. The compressibility of clay, on the other hand, is higher, involving both consolidatio n or removal of water (Terzaghi and Peck, p. l 5) and compression . Consolidation and compression of clay may be a slow process due to its low permeability, rendering removal of water difficult. Organic silts and clays may be highly compressible, due to the p resence of organic matter s ubject to decay. More compressible than silt or clay is peat, which is an aggregate of macroscopic and microscopic fragments of plant ma tter with varying amounts of mineral ad!Jlixed. High porosity, weak skeletal structure, and loss of material as a result of decay render it highly compressible . Studies by Kaye and Barghoorn (1964) have shown that it is subject to considerable compaction even under its own weight, and Bennema eta!. (1954) report that compaction may be as high as 85-95 %. This property makes peat a generally unsatisfacto ry subject for construction of absolute sea-level curves. The above-mentioned factors indicate that age/depth graphs of sea-level change

PHYTOGEOG RAPHIC HISTORY OF T H E ISTHMUS OF PANAMA

271

are not necessarily true representations of the course of changing sea level; graphs of uncorrected data fr om unstable areas which show changing land/sea relationships are . curves showing relative sea-level change. A number of authors, notably Jelgersma ( 196 1), McFarlan (1961), Coleman and Smith ( 1964) and Kaye and Barghoorn{ l964) have a ttempted to correct sea-level data for subsidence a nd compaction of the underlying sediments. Additional c~rves depicti ng eustatic sea-level change have been constructed using data solely from tectonically stable areas {Shepard, 1960, 1963a, b).

Sea fe,,e/35,000-18,000 B.P.

The course of eustatic sea-level change beginn ing with sea level 35,000 years ago is of particular interest to this study, as we have discovered evidence of a former sea level of that age in Panama. The details of sea-level change d uring this period are not well documented for a number of reasons. Although a number of investigators have fou nd evidence of high stands of sea level correspond ing to the interglacial warm climates 80,000 years ago or older (see Emiliani and Rona, 1969, for a table and list of recent references), little trace has been found of a high or relatively high sea level during this period . There is mounting evidence that temperature s during this interstad ial did not rise to equal those of the interglacials; it is likely, therefore, that this high sea stand was well below that of the present and previous interglacials. During the period of lower sea level, deposition would have been far out on the shallow continental shelves, and such depo~its would probably have been buried deep under the tong sedimentary column which has accumulated since then. If, during th is period, sea level rose fo r a time, then fell again before beginning the final climb to its present level, the erosion base-level would also have been lowered, causing erosion of a substantial part of this sedimentary record. One of the few studies dealing partly with sea level during this period was carried out by McFarlan (1961), who analyzed over one hundred radiocarbon-dated samples from known deposi tional environments from southern and offshore Louisiana. The samples were deposited in a variety of environmen ts at or close to sea level, ranging from flood plains above sea level to the Gulf floor below the surface; therefore, it was necessary to adjust the level of many of the samples to show actual sea level at the time of their deposition. A second type of correction was necessary for samples not deposited on the "hinge line", a zone of no structural movement between uplifted sediments inland and seaward downwarped sediments of the Mississippi Delta. The level of samples located in the thick sedimentary wedge deposited by the Mississippi River on the "Prairie", or last interglacial surface during the last rise of sea level was adjusted to compensate for post-depositional subsidence. McFarlan's (1961) ingenious method for this correction, which he admits is "tenuous and involves a number of assumptions which are not strictly valid" (p.J42) is as follows. He has reconstructed what he believes to be the former level and shape of the now-downwarped Prairie surface. Each point on this surface has undergone a

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PHYTOGEOGRAPHrC HISTORY OF THE ISTHMUS OF PANAMA

determined change o f level. Of this total change of level, a fractio n may be atlributed to pre-depositional sinking caused by sed imen ts deposited seaward of that point, and another frac tion to ~cd imcnts burying the point after its deposition. By subtracting the fract ion of the to tal amount of subsidence which was due to post-depositional sinking from the present depth below sea level of tha t point, sea level at the time of its deposition may be determined. Similarly, the posi tion of any point wit hin the sedimentary wedge may be expressed as a fraction, witll.the number of feet of sed iments deposited after its burial as numerator, and the depth of the entire sedimentary wedge as denominator. Knowing the total subsidence of the Prairie s urface below that point, one may then compute the portions of this subsidence due to pre-depositional and post-depositional subsidence. As a result of his study, McFarlan concluded that at some time prior to 35,000 years ago the sea fell to a level at least 450 ft. below that of the present. From that low level it fi rst rose to about -250ft. before 35,000 B.P. and remained at t hat level until about 18,500 years ago, when it resumed rising. A stillstand such as that postulated by McFarlan was considered very unlikely by Broecker (1961), who believed that a cold o scillation occu_rred between 25,000 and 18,000 years ago; as evidence, he cited advance of the A merican mid-continent ice sheet (Flint and Rubin, 1955), expansion of the Great Basin inland lakes (Broecker a nd Orr, 1958; Flint and Gale, 1958), cooling of the climate after the Paudorf interstadial (26,000 B.P.) as suggested by European pollen sequences (De Vries, 1958), and a drop in ocean surface temperatures about 25,000 years ago shown by oxygen-isotope and coarse-fraction data on deep sea cores (Emiliani, 1955; Broecker et al., 1958), all of wh ich imply a concurrent lowering of sea level. Broecker's view that a stillstand at -250ft. fro m ca. 35,000 B.P. to 18,000 B.P. could not have occurred is supported by data presented by Curray ( 1961), who found no evidence of a protracted stillstand on the continental shelf of Texas; Curray believed that such a stand would have had a considerable effect o n part of the Texas shelf, resulting in detectable terraces, submerged d eltas, shore-line d eposits and similar features. Curray (1960, 1961), b as presented several rad iocarbon-dated samples from the "Freeport Rocks" off Freeport, Texas, as evidence of an interstadial and high sea !~vel about 30,000 years ago. Shells of Crassostrea 1•irginica from coquina and beach rock comprising the p innacles which Curray believed probably represent the remnants of a beach-line development at about -8 fatho ms (48 ft. ) gave a date of 26,900 ± 1,800 years; an additional sample composed of shells of Rangia cuniata and Crassostrea virginica was dated at 32,000 ± 3,500 B.P. Evidence of a higher sea level also comes from the Atlantic continental shelf of the United States. Milliman and Emery (1968) have obtained radiocarbon dates from oolites, Mercenaria campechiensis and Crassostrea virginica shells, and salt-marsh peat. On the basis of these dates, they concluded that sea level was near that of the present from about 30,000-35,000 years ago. Samples from Laguna Madre, near Carvajal, Tamaulipas, Mexico, may support

the evidence for a higher stand of the sea. Beach rock approximately at sea level and 3 ft. above sea level yielded dates of 24,900 ± 700 B.P. and 35,200 ± ~:gg B.P., respectively (Pearson et al., 1965; Behrens, 1966). The collector of the sa mples, E. W. Behrens, believes t hat there is a possibility that the dates are too young, and is of the opinion that the samples may be of Sangamon age. An additiona l recent date of fossil beach shells from ca. 8ft. above sea level in a bluff on the northeastern shore of Bahia Salada near the point at which this bay enters Laguna Madre, near Carvajal, Tamaulipas, is 1940 ± 60 B.P. (Pearson et al. , 1966; Behrens, 1966). E. W. Behrens, the collector of these samples, notes that this date, together with an earlier date from the same loca lity, 2,340 ± 100 B.P., correlates with dates from similar elevations from Brazil and Australia (Van Andel and Labore!, 1964; Fair bridge, 196 1a) and may therefore be evidence of a Recent stand of sea level hig her than that of the present. He considers, however, t hat t he deposits may instead reflect local uplift ; if that is the case, it is possible that sea levels of 24,000 and 35,000 years ago at this locality were actually somewhat lower than indicated by the evidence. Additional radiocarbon-dated samples yield ing information on sea level during this period come from Hawaii, the stability of which is, however, quest ionable. Shells from 5- and 12-ft. elevated terraces gave dates of 24,000 ± 700 and 31,400 ± I ,200 B.P., respectively (Shepard, personal communication cited by Curray, 1961; and Shepard, 1963a, p :268). However, other finite radiocarbon measurements of material from emerged Hawaiian reefs include dates which range from 26,640 ± 1,100 B.P. to 15,000 ± 600 B.P., including several dates of ca. 18,000 B.P. (Hubbs eta!., 1965). As sea level was unquestionably not at this position during this entire period, the validity of at least some of these dates is suspect. Evidence of a possible high sea stand during this period in the Bristol Channel area of England is cited by Donovan (1962). H owe Rock Platform, which lies partly beneath boulder falls attributed to frost weathering during the last major g lacial advance ("You_nger Wi.irm") and situated beneath beds correlated with late-glacial and postglacial climatic sequences, is thought by D onovan to have been cut when mean sea level was ca. 20ft. (6- 7 m) below its present level. Since this Carboniferous limestone terrace is better preserved than Monastirian erosion features, Donovan believes that it must be younger than they are, and on the basis of Zeuner's (1955) correlation of the latest Monastirian phase with the Gottweig interstadial, concluded, with ApSimon et al. (1 96 1), that the platform must h ave been cut later than Gottweig and earlier than the "Younger Wi.irm", and must therefore have been cut ca. 24,000 years ago during the Paudorf interstadial. D onovan considers, therefore, tha·t this feature from the Bristol Channel supports Curray's (1961) evidence for a h igh stand of the sea ca. 26,900 years ago at Freeport Rocks, although the latter's second date from that location of 32,500 B.P. does not correspond as well.

273

274

A. S. BARTLE TT AN D E. S. OARGHOORN

Climati c el'idencejfom continen tal deposits Adding to uncerta inty about sea level during this period is the fact t hat radioca rbon dates provid ing evidence of a high stand were from carbona te samples, which are an unreliable source for radioca rbon dates in the range greater than about 25,000 years (Broecker,. L965). Taken by itself, the available dire<;t evidenc e of sea level at this t ime is scant and could be overloo ked easily, if it were not support ed by supplementa ry indirect climatic evidence from continental deposits and deep oceanic cores. T here exists a growing body of information providing evidence of an extended warm period, or series of warm periods , extendi ng from ca. 50,000 to ca. 24,000 years ago. The evidence comes from a number of d isciplines, and originates in a variety of widely scattered areas. In the United St ates and Canada , evidence exists in Oregon and Washington of an interglacial (or interstad ial) from ca. 35,000 to 22,000 B.P ., the Olympi a l nterglaciat ion (Crandell, 1965). It is not clear from the evidence whether one wa rm period existed through this entire interval, or whether there were two warm periods, separated by a colder interval . Peats fr om Vancouver Island assigned to _the Q uadra sediments of the Olympia Intergla ciation have yielded radioca rbon dates ranging from 41,500 B.P. to 23,450 B.P. (Dyck et al., 1966; Fy1es, 1963). Pollen analysis by Heusse r (1 964) of a bog near Humpt ulips o n the Olympic Peninsu la shows a Middle to Late Wisconsin interstadial, with a radioca rbon date of 27,400 Âą 2,000, during which the July average temperature was inferred to be 2oC below today's. A J uly average temperature cu rve for the Humptu lips section was elabora ted by Heusser by match ing modern pollen spectra from the vicinity of weather stations scattered along the coasts of British Columb ia and Alaska with the fossil spectra , and recordin g the corresp ond ing July average tempera ture. In the Rocky M ountain s, mature zonal soils in cirques and summit areas separatina the Bull Lake and Pinedale glacial deposits a nd also the advances of the Bull 0 . Lake Glaciat ion are interpre ted as suggesting deglacia tion of the Rocky Moun tams at least as far north as G lacier-N ational Park (Richm ond, 1965). D eposits of t he Bull Lake-Pinedale Interglaciatio n are assigned by Richmo nd to a period from about 32,GOO B.P. to ca. 25,000 B.P. To t he east, in souther n Ontario , a long, cool interval, the Port Talbot interstadial (which may be d ivisible into two periods, the earlier Port Talbot interstade and the later Plum Point intersta de) terminated only about 25,000 to 27,000 years ago. After the Plum Point interstade, souther n Ontario was once again covered by an ice sheet (Goldth wait eta!., 1965). I n norther n Dlinois and souther n Wiscon sin, the Farmda le substage, with a radioca rbon age of about 31,000 to 29,000 B.P., was a brief but intensive glaciation, with ice moving in from the east from the North Bay, Ontario area (Leighton and Brophy, 1966). Following this brief glaciatio n was the Farm C reek "intragl acial", a term used by Leighto n and Brophy (p.481) "for the interval s between substages be-

PHYTO GEOGR APHIC HISTOR Y OF TH E ISTH MUS OF PANAM A

275

cacrse t hey arc mo re significa nt than the intervals between the stad ials of the Tazewe ll substag e". This was a short , mi ld period during wh ich the Farmdale glacial lobe stagnat ed and melted rapid ly, causing g reat floods along the Mississi ppi, M issouri, and Ohio Rivers. Accord ing to these authors , the Farm C reek intraglacial lasted about 4,000 years, fro m ca. 28,000 B.P. to ca. 24,000 B.P., as indicate d by radioca rbon dates. T his interval was then followed by the Iowan glaciati on . I n Ohio, the advancing ice of the " Late" W isconsin entered more than 25,000 years ago and reached its souther nmos t position 20,000 years ago in the Miami Lobe and 18,000 years ago in the Scio to Lobe (G oldthwa it, 1958; F orsyth, 1961). The history of this a dvance is documented by a n umber of radioca rbon dates m ost ly from spruce wood buried in the till of the advanc ing ice (Goldth wait eta!., _1965) . Ice also reached its maximu m extent in Wisconsin 19,000- 20,000 years ago in the W oodfordia n Substage, when the Lake Michigan and Erie Jobes advanced as far so uth as central Illinois (Frye et a!., 1965). Tn the Lake Erie region, there is evidence that a long, cool non-glacial period separat ed the Early from the Late Wisconsin. This period, the Port Talbot intersta d ial, began more than 48,000 years ago and e nded 28,000- 24,000 years ago with the Plum Point interval (D reimanis ct a!., 1966). In the Texas High Plains, pollen and inverte brate data similarly indicate a climate slightly _cooler and more moist t han today's d uring the Rich Lake Interplu vial 22,000-32,000 years ago (Wendorf, 1961). Accord ing to Mart in and Mehrin ger ( 1965), additio nal evidence exists that this period was charact erized by a relatively mild climate immediately preceding the full glacial a nd corresp onding to the Plum Point interstadial and t he Europe an Paudor f oscillat ion. T his intersta dial is represented in Austria by the P audorf, which ended abou t 28,000-32,000 B.P.; its beginn ing has not yet been establis hed. In The Netherl ands, the Deneka mp and Hengelo interstadials, dated from 32,000 to 29,000 B.P. and 39,000 to 37,000 B.P., respecti vely, constitu te th is period (Van der Hammen et a!., 1967; Vogel and Vande r Hammen, 1967). These authors have concluded as a result of their study of soils, periglacial features, and pollen that this period was slightly less cold and perhaps more hum id than the intervals precedi ng and following. In Siberia, recession of the Zyrians k Glaciat ion took place 33,000 years ago, and the period d uring the Kargins k Interglacial or intersta dial 30,000 to 24-22,000 B.P . was marked by a climate somewhat warmer than that of the present. This was followed by the coldest period and glaciati on in the mounta ins from 24-22,0 00 to 14-13,000 years ago (K ind, 1965). An interesting recent study of variatio n in oxygen -isotope composition of ice from the Greenla nd ice cap also gives evidence of this intersta d ial; a period with a relatively high (1 8 0 ), reflecting higher tempera tures, is found about 29,000-35,000 B.P. (Dansg aard et al., 1969).

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A. S. BARTLETT AND E. S. BARGHOORN

PHYTOGEOGRAPHIC HISTORY OF THE JSTHMUS OF PANAMA

EWdencefrom oceanic cores

about - 425ft. from about 21,000 to 16,000 years rather than 18,000 or 19,000 years ago, and did not begin its upward climb unt il about 14,000 years ago.

Analysis of 180/160 content and 230Thf231 Pa dating of deep-sea cores carried out in recent years has shown that this interstadial is recorded in ocean sediments also. Emiliani, in a recent paper in a series on this subject, has provided data indicating that there was a temperate age ("Ocean stage 3") from about 55,000-25,000 years ago. His data, which come from cores from the Atlantic Ocean and adjacent seas and the Mediterranean Sea, indicate that temperatures during this period did not rise as high as those of t he preceding or following (present) interglacial (Emiliani, 1971). Another study of sediments from the And a man Sea and the Bay of Bengal has similarly yielded evidence of this warm period. Reduced relative abundances of the G/obigerina rubescens complex indicates an interstadial lasting from about 42,000 to 22,500 years ago (Frerichs, 1968). There is evidence from many areas, therefore, wh ich suggests that climate during this Middle Wisconsin period was not as severe as that during the Early Wisconsin (before ca. 55,000 years ago, according to Emiliani's, 1966, time scale) and the Late Wisconsin (25,000-10,000 years ago). This supports the hy_pothesis that sea level during th is period was below that of the present and above the very low sea level reached during the height of the last glaciation, about 18,000 years ago. Defin ition of the precise course of sea level during this period must, however, await new and more precise evidence. Âˇ Sea lel'el 24,000- 18,000 B.P.

Following a possible high stand of the sea about 35,000 years ago and 28-24,000 years ago, sea level must have fallen until about 18,000 years ago, concurrent with climatic deterioration. Curray (1960) suggested that sea level stood at about -65 fathoms (390ft.) between 18,000 and 20,000 years ago, and later found corroborating evidence on the continental shelf south of Mazatlan, Mexico (Curray, 1961). Shells of Strom bus granu!atus, a shallow-water organism with a living depth range of 1- 10 fathoms, were , obtained from the shelf at a depth of 62.5 fathoms, and were dated at 19,300 Âą 300 B.P. Curray notes that the stability of this shelf has not yet been substantiated, although a study of shoreline features has suggested that the a rea has been relatively stable during this period. Another estimate of sea levell8,000 years ago at the height of the Late Wisconsin by Shepard and Curray (1965) is - 125m (-410ft.); sea level, they believe, was probably closer to that of the present during a preceding interstadial. Broecker (1961), who considered the stillstand at -250 ft. from before 35,000 B.P.- 18,500 B.P. postulated by McFarlan (1961) to be very unlikely, concurred with the hypothesis that sea level feU between 25,000 and 18,000 years ago. Milliman and Emery (1968), however, conclude from their investigation of the Atlantic continental shelf of the United States that sea level fell rapidly to a depth of

277

Sea leve/18,000- 10,000 B.P.

Owing to a scarcity of reliable dates older than about 10,000 years B.P., little detail is known of the course of rising sea level fro m about 18,000- 10,000 years ago. Curray Âˇ {196~ 1961, 1965) has suggested, on the basis of his studies of the shelf ofthe Gulf of Mexico, that sea level had risen to about -45 fathoms (- 270ft.) by about 16,000 B.P., and to about - 25 or possibly -22 fathoins(- 150or 132ft.) by about 10,000 to 12,000 years ago during Two Creeks time, with some fluctuation. Subsequently, it receded to about -35 fathoms (- 210ft.) sometime between 10,000 and I I ,000 years ago before resuming a rapid rise. Milliman and Emery, however, found no evidence of these flu ctuations. They stress, in p~rt icular, that their evidence that the Holocene transgression began 14,000 years ago is in accord with Emiliani's findings that a sharp increase in smface tempe1ature to.ok place in the Caribbean 15,000 years ago. A more common estimate for the start of this transgression is 18,000- 19,000 years ago, a figure which is based on evidence of the beginning of glacial retreat in North America. Sea level /0,000 B.P. to present

Many curves depicting eustatic or relative sea-level rise during the period from about 12,000 years ago ~o the present have been constructed; an excellent comprehensive review and summary of many of these has .been published by Jelgersma (1961). Figures showing the chronology of sea-level rise during the last 19,000 years, using a large number of dates from widely scattered stable areas of the world have been pu~lished by Shepard (1960, l963a,b; see Fig.5). Dates from a number of additional studies in relatively stable areas (for example those by Godwin eta!. (1958), Jelgersma and Pannekoek (1960), and Jelgersma (1961) agree nicely with those of Shepard. Other studies, for example tho~e of Curray (1960, I 961, 1965) and Fairbridge (I 96 Ia,b, 1962) show the course of rising sea level in the form of detailed curves. Since sea-level rise during this period was undoubtedly complex, these curves of eustatic sea level differ in detail, but show general agreement in outlining a rapid rise up to about 7,000 years ago. The rate of sea-level rise from 7,000 B.P. to the present, however, is the subject of a controversy centering partly on the question of when the sea attained its "present" leveL Kaye and Barghoorn (1964) and Kaye (1964) point out that sea level has probably been fluctuating by as much as 1 ft. above and below the present zero datum during the last few thousand years. Kaye (1964), extending Marmer's (1952) tidal gauge observations which showed a steady progressive rise in sea level along the Atlantic coast in the 20-year period from 1930 to 1950 averaging 0.02 ft. per year, reports that the sea-level record at Boston shows that sea level in the mid-nineteenth century was

278

A. S. BARTLETT AND E. S. BARGHOORN

PHYTOGEOGR APHIC HISTORY OF T HE ISTHMUS OF PANAMA I

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almost.equal to tha t of the mid-twentieth century, and that it was almost 0. 5 ft. lower in the late nineteenth and ea rly twentie th century. Kaye (personal communicatio n, 1966) reports that sea level has evidently reached the peak of the current fluctua tion, and is beginning to decline. It is clear, therefore, that st udies of former sea levels dealing with the last several millennia must defi ne "present" sea level as including the range of va riability intro~ duced by these r.elatively short-term fl uctuations. ·Divergent opinions abou t the co urse of rising sea level during the past 7,000 years, which may be d ivided into four categQries, are: (1) that sea level has risen at a stead ily decreasing rate up to the present time; (2) that sea level rose until about 5,000 or 3,000 B.P., then halted; (3) that sea level has fluc tuafed widely during this period, and that it has risen well above its present level at least once d uring t he Holocene transgress ion ; and (4) that the co ur-se of sea level during this period is not yet known with certainty. Among those expressing the view t hat sea level reached its present level several tho usand years ago are Fisk ( 1944, 195 1, 1956, 1959), Le Blanc and Bernard (1954), Fisk and McFarlan {1955), Godwin et al. (1 958), Fisk and McClelland (1959), Gould and McFarlan (1959), Kaye (1959), Fairbridge (196 1a), McFarlan ( 1961), Coleman and Smith (1964), a nd Kaye and Barghoorn (1%4). Fisk (1944, etc.) and Fisk and McClelland (1959) concluded from data from the Gulf Coast of Louisiana that the present stand of sea level was reached ca. 4,500-5,000 years ago; in a recent letter to Kaye (cited in Kaye and Barghoorn, 1964), Fisk concluded fro m stud ies of the Texas barrier islands that present sea level m ay have been reached by about 4,000 B.P. Other estimates of the time when sea l evel "reached its presen t stand include 3,000 years ago in Boston, Massachusetts (Kaye and Barghoorn, 1964) and Lou isiana (Gould and McFarlan, 1959; McFarlan, 1961) ; 4,000 years ago in PL1erto Rico (Kaye, 1959); 5,000 yea rs ago in Louisiana (Le Blanc and Bernard, 1954) and 2,000-5,000 years ago in south-central Louisiana (Coleman and Smith, 1964); 5,500 years ago as indicated by a world-wide collection of samples (Godwin, et al., 1958); and 6,000 years ago, again from world-wide data (Fa irbridge, 1961a,b; !962). Fairbridge's curve is distinctive in showing oscillations of up to 10 ft. a nd more above and below present sea level in the period since 6,000 B.P. Among those expressing the opposi te view, that sea level has risen at a steadily decreasing rate up to the present, are Bennema (1954), Shepard and Suess ( 1956), Scholl and Stuiver (1965), and Spackman et al. (1966). Shepard (1960) reported evidence suggesting that sea level did continue to rise very slowly up to the present, but felt that the data might be deceptive; in 1965, Shepard and C urray expressed uncertainty about sea level during the past 6,000 years, but were of the opinion that if sea level has been stable during this period, supposed stable areas which were a source for sea-level data have been subsiding slowly. These areas, which are listed in Shepard's chronology of postglacial rising sea level (see Fig.5), show that sea level about 6,000 years ago was at approximately -20ft.

280

A. S. BARTLETT AND E. S. BARGHOORN

Add itional evidence about sea level at this time is provided by an archaeological site at Boston. Detailed studies of the site of an ancient fishweir constructed by Indians (Johnson et al. , 1942 ; Barghoorn et al., 1949) shqw that sea level prior to its construction was at about -23 feet 5,600 yean, ago (date p ubl ished by Valaslro and Whitaker, 1962), which is well wi thin the range of sea level at this time as established by Shepard. Evidence based on stud y of Recent sediments underlying mangrove swamps of southwestern and sout.h F lorida indicates a 12-ft. submergence of the seaward margin of the ÂˇEverglades, b orde1ing mangrove swamps, and three Florida keys from about 6,500-7,000 B.P. to the present (Scholl and Stuiver, 1965; Scholl et al., 1969). The submergence, which h as proceeded at a steadily decreasing rate can, according to the au thors, be ascribed largely to absolute changes in sea level, as they believe that good evidence exists implying coastal stability for southern Florida. Spackman eta!. (1966) found clear-cut evidence jn another study from southwestern Florida of a relative rise of sea level and a transgression of the Gulf of Mexico over the coastal area throughout the last 4,000 to 5,000 years. During the early part of this period, the accumulating peat contained comparatively small amounts of mineral matter, demonstrating that the rise in sea level must have OJ~Iy slightly exceeded the rate of accumulation of organic material. However, peat formed after about 3,000 years had a higher mineral content, possibly implying, according to the authors, a more rapid rate of transgression and relative sea-level rise. Unlike Scholl and Stuiver, Spackman et a!. feel that they possess no data capable of resolving the question of whether the transgression is due to an absolute rise in sea level, to subsidence of the la nd, or a combination of these factors. The third view, that sea level has fluctuated widely during this period, and that it has risen well above its present level at least once during the Holocene or Flandrian transgression (a term originated by Dubois, 1924, for the entire transgressive sedimenta ry sequence of early and mid-Recent time) is more difficult to substantiate. If sea level d uring this period fluctuated as postulated by proponents of this view, supporting evidence would necessarily be Jess abundant, as sediments deposited by brief transgressions would be eroded easily during intervening periods of lowered sea level. Evidence in support of Recent high stands of sea level is presented by Umbgrove (1950, 1951), Schofield (1960), and F air bridge (196 la,b; 1962); it has been reviewed by Jelgersma (1961). Umbgrove, who drew his conclusions prior to the development of the radiocarbon-dating method, postulated that sea level must have been approximately 6 m higher than at present until it began to fa ll about 4,000 years ago. Umbgrove reached t~1is conclusion because he doubted that peat beds could have formed in the coastal Netherlands except under conditions of a retreating sea, an idea that was shared, acco1ding to Jelgersma, with F lorschiitz (1954), Kuenen (1954), and Van Giffen (1954). Bennema (1954), however, did not consider lowering of sea level a prerequisite for peat formation, which he thou ght could occur when salt water is excluded by formation of offshore bars or closing of inlets. Schofield's (1960) curve of sea-level change in the Firth of Thames, New Zealand,

PHYTOGEOGR APHIC HISTORY OF THE ISTH M US OF PANAMA

281

during the last 4,000 years shows a fall of2 m during this period; Schofield's contention that the area u nder study is relatively stable was contradicted by-Jelgersma ( 1961), who stated.that the region in q uestion is probably in a mobile belt. Fairbridge (196 la,b; 1962) concluded from his observations of data from both hemispheres that sea level rose several meters above its present stand four times between 6,000 B.P. and the present. These transgressions, which were separated by regressions during which sea level fcll.2-4 m below that of the present, were named the Older Peron Submergence ( - 3 to - 5 m or 10 to 15 ft.; 6,000-4,600 B.P. from the midpoint of the transgression to th e midpoint of the following regression), the Yo.unger Peron Submergence (-3 m or !0 ft. ; 4,000-3,400 B.P.) the Abrolhos Submergence ( - 1.5 to 2 m or 5 to 6 ft. ; 2,600-2,100 B.P.) and the Rottnest Submergence( -60cmto I m or 2to 3ft. ; ca. 1,600-1 ,000 B.P.). Jelgersma (1961) challenged the validity of Fairbridge's conclusions, as she was of the opinion that the latter's data supporting high sea-level stages have been drawn mainly from region s of questionable stability. Shepard (1 963a) similarly was skeptical of the evidence for postglacial high sea-level stands, as, in his opinion, "M ost or all of the evidence for a postglacial higher stand comes fro m the stable Australian block or from coasts known to be unstable. The Australian evidence is thrown into doubt by finding dates for the 12-ft. terrace of respectively 900 years, 2,000, 4,000, 6,000 and more than 25,000 years." (p.268). In a later publication Shepard and Curray (1 965) reiterate this view, stating that low terraces and raised reefs of the islands of the Pacific and Australia a re proving to be older than Holocene. Among those who doubt that sea level has been appreciably above the present level since retreat of the Wisconsin ice are Shepard and Suess (1956), Jelgersma (1961 ), Shepard (1963a), Coleman and Smith (1964), Shepard and Curray(1965), Scholl eta!. (1969), and members of the Carmarsel Exped ition (see later). Shepard and Suess state that, according to Van Straaten's (1954) work, samples from the North H olland area in The N etherlands and from the United States Gulf Coast give no indication of a postglacial sea level higher than that of the present. A more recent stuoy of coastal deposits in The Netherlands by Jelgersma (1961) also shows no evidence of a higher sea level during the last 8,500 years. Jelgersma's curve of eustatic sea-level change is based on fifty-two radiocarbon dates obtained from peat. The curve shows a rapid rise of sea level between 8,300 and 7,000 B.P., after which there was a gradual decline in rate of rise. The portion of the curve between 6,000 and 3,000 B.P. is determined by twenty-seven dates; the longest interval between two consecutive dates is 400 years, which, in Jelgersma's opinion, precludes a ny undetected major fluctuations during this interval. Jelgersma cites additional examples of relative sea level studies in The Netherlands, which concur in rejecting the hypothesis of Recent high sea-level stands. In the United States, Coleman and Smith (1964) found no indication in southcentral Louisiana that sea level had been higher than at present at any time during the past 7,000 years. Redfield and Rubin (1962) in their studies on Cape Cod, also fo und

282

A. S. BA RTLEIT AND E. S. BARGHOORN

no evidence of higher sea level t han at p resent at any time since the Wisconsi n. Scholl and S luivcr ( 1965) and Scholl et al. ( 1969) report that evidence from Florida suggests that sea level has not risen appreciably (if at all) above its present level d uri ng the last 4,400 years. The Carma rsel Expedition o f the Scripps Institution of Oceanography to the Caroline and Marshall Islands was organized in an allempt to resolve the q uestio n of the course o f sea level ~ise during the last 6,000 years (see C urray et al. , 1970; Newell and Bloom, 1970; Bloom, 1970; and Shepard, 1970). Members of the expedition, in an attempt to discover whether a stand of the sea higher than that of the p resent had taken place d uring this period, studied features such as cemen ted rubble ramparts and ru~ble ridges some of which had been mistaken for emerged reefs a1~d cited as evidence fo r a "+2-m" postglacial stand of the sea. N o corals or Tridacna shells were found in growth position in any of these featu res; such fo rmatio ns, therefore, do not give clear evidence o f sea level at the time the organisms lived. The flat tops of the cemented ru bble ramparts arc usually about 1. 5 m above the surrounding reef flat and are completely submerged at high tide. According to the authors (Curray et al., 1970, p. J874): "Cementation of the ru bble apparently occurs primarily beneath the surface of the islands, a nd locally on the seaward reef flat or rubble beach where it is wetted with spray. The cementation level must be controlled by- the water table, which is in turn controlled by high tide levels ... For this reason, many of the cemented rubble ramparts observed have horizontal upper surfaces at approximately high semidiurnal levels. A s the islands migrate to leeward in response to the wind and the sea, the cemented remnants of formerly mo re continuous ridges a re left behind on the windward sides." The formation of such features is, therefore,~ continuing presentday phenomenon. Thus, the data gathered by this expeditio n do not support the hypothesis that sea level was higher t ha n at present during the last 6,000 years. Peat samples collected by members of this expedi tion provide dates which support the hypothesis that sea level rose slowly from 7,000 to 4,000 B.P.

Eustatic sea-level change in Panama

Introduction The low sea-level phase of the last major cycle of sea-level flu ctuation associated with the Wisconsin Stage initiated a period o f erosion of the Tertiary basement rocks of the Gatun basin. The majo r strea ms of the basin, i1,1cluding the Trinidad, Chagres and Gatuncillo Rivers, scoured their beds, resulting in a very deeply dissected topography of great relief. During this period of erosion, the Chagres River, for example, eroded its chan nel to a depth of 300 ft. (personal communicatio n from R. H. Stewart, 1967). Later, the rising sea accompanying t he late-glacial and postglacial climatic

PHYTOG EOGRA PHIC HISTORY OF THE IST HMUS OF PANAMA

283

amelioration caused deposition on this eroded surface of marine sediments at fi rst and later, a complex series of' interbedded alluvial gravel, sa11d, silt, clay an d peat: These marine, swamp, and alluvial deposits which fill the Gatun basin to a depth of as much as 300 ft. and extend inland as far as G amboa, were collectively given the informal designatio n of "Atlantic Muck" (Thompson, 1947). Review o f the geologic history 9f the Gat un Lake area indicated that it has probably been sta ble d uring late-glacial and postglacial time. Therefore, it seemed likely that the sediments filling the basin co uld, in view of their depositional history, p rovide valuable information about the course of rising sea level.

Mangro1â&#x20AC;˘e pollen as a sea-lelÂˇel indicator Pollen analysis of samples from eight of the cores drilled in these sediments showed that the pollen of Rhizophora comprised a considerable portion of the total pollen in many of them. Muller (1959) had noted that this genus is a prolific pollen producer, a nd is appar<:ntly wind-pollinated; he o bserved personally that mangrove flower s o n the Orinoco delta are rarely visited by insects due to t he strong sea breeze, and thus considered this genus to be well-adapted to its peculiar environment with respect t o its pollination mechanism. Rhizophora, known as the "red mangrove", is the principal genus of coastal mangrove swamps along tropical and subtropical coasts throughout the world. Rhizophora, together with other genera comprising mangrove vegetation s uch as Avicennia (Verbenaceae), Conocarpus (Combretaccae) and Laguncularia (Combretaceae), typically grows on sheltered muddy shores with a prograding coastl ine (Chapman, 1944), and may ex tend inland along estuaries and tida l rivers approximately to the limit of salt-water influence (Van dcr Hammen, 1963; and others). Althoug it may grow and survive in fresh water to a limited extent as it does in Surinam where scattered trees occur beyond the limit of salt-water influence ( Lindeman , 1953), Rhizophora thrives best in water with a salt concentration at least one-th ird that of sea water (Grah-am, 1964). In Panama, shores protected from wave action are bo rdered with mangrove vegetation, which f orms extensive thickets in many places. On the Atlantic coast, Rhizophora extends inla nd along the Chagres River to the limit of tidal influence at G atun. On the Pacific coast, tidal influence and mangrove vegetation extend inla nd to the fi rst locks at Miraflores (Standley, 1928). As a consequence of the peculiar habit and pro lific pollen p roductio n of its parent, Rhizophora pollen is an excellent facies indicator and may be employed p rofi tably in studies of former sea levels. Several individuals, recognizing the po ten tial utility of this pollen in sea-level investigations, have undertaken studies o f its presentday transport and d eposition, and have attempted to define the relationship of sediments bearing this pollen to the ecological and vegetational characteristics of the source area.

284

A. S. BARTLElT AND E. S. BARG HOORN

Muller (1959) undertook detailed studies of the source, transport, and final deposition of pollen in the Orinoco delta. As a result of this investigation, he discovered several relationships bct~cen mang1 ove vegetation and the Rhizoplwra-pollen content of nearby sediments which arc of particular interest in connection with sea level studies. Since his study had dealt with a limited area only, Muller recommended that investigators dealing with other regions should not extrapolate indiscriminately from his conclusions. Certain of his results were, however, confirmed by Van der Hammen (1963) as having validity also for British Guiana, and a third independent study conducted by Spackman et al. (1966) extended the applicability of these conclusions to Florida, as well. The conclusions reached by the above-named authors may be su mmarized as follows. (1) Pollen assemblages in analyzed sediments accurately reflect the ecological frequency of Rhizophora, and ecological boundaries similarly are generally fairly accurately reflected in the pollen assemblages of surface sediments (Spackman et al., 1966). (2) The percentage of pollen of Rhizophora plus A tâ&#x20AC;˘icenniq in a mangrove swamp may be between 45 and 95%. Narrow fringes of mangrove have lower percentages, such as 30% (Vander Hammen, 1963). Nearshore sediments in front of mangrove swamps may contain from about 30 to 50~ Rhizophora pollen (Muller, 1959). (3) Sediments in swamp forests immediately behind the mangrove may contain 45- 10% or less Rhizophora pollen, while those farther inland may have 10% or less (Vander Hammen, 1963). (4) Large, heavy grains such as those of Symphonia (Guttiferae) tend to settle close to the coast line (Muller, 1959), and are rarely found in offshore sediments in any appreciable percentage (Vander Hammen, 1963). The lighter and smaller grains, on the other hand, are transported more easily, and may settle far from shore.

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289

Pollen analysis of samples from eight of the cores drilled in t he Gatun basin sediments showed that the pollen of Rlrizophora is present thro ughout most of the sedimentary co lumn, and comprises a high percentage of the total pollen in ma ny of the core samples. The content of Rltizophora pollen varies from a low percentage (5% or less) in some of the samples from the lower third of the column (ca. I 10- 162 ft. below sea level) shown in Fig.7 to over 90 % in core T DS-4 (Fig.9). Most samples from the middle of th!,! column (ca. 110-28 ft. below sea level) contain high percen tages of Rhizopfwra pollen. Seventeen of a total of thirty samples in this interval contain over 30% ; of these, eleven have over 45 %. and seven ~ver 60 %. Pollen accompanying that of Rhizophora at levels below 109ft. is primarily that of rainforest trees and Urticales, which represent in great part" plants growing·typically in disturbed environments. Pollen of swamp genera is, on the other hand, virtually absent throughout this interval (see Fig.3). Many of these samples are sandy or gravelly, and some contain hystrichosphaerids, which are marine ind icators (Muller, 1959). Inspection of Fig.2 shows that none of the cores is more than about 2,500 ft. fro m land above the 100-ft. contour; at the time of deposition of the lower third of the sedimentary column, when sea level was 100ft. o r more below its present stand, the depositio nal sites were even closer to the shore line. Additional evidence for neaishore deposition is the presence of pollen of Symplronia, and other large pollen such as that of Mendoncia (Acanthaceae), Quararibea (Bombacaceae), Ochroma (Bombacaceae) and the Malvaceae. A low percentage of Rlrizophora pollen, virtual absence of pollen of swamp plants, and the presence of large, heavy g rains thus indicates deposition very close to sea level in front of the coast line, rather than behi nd it in a swamp. Samples from about 110 ft. to about 28ft. below sea level, most of which have a high frequency of Rhizophora pollen, were undoubtedly deposited in or very near mangrove swamps; some are highly organic a ncLsomewhat peaty, also containing many woody fragments. Several contain oyster s hells (samples no. 145 and no. 68 contain whole shells), one of which bears the imprint of a root. Standley (1 928) reports, in his description of Panama mangrove swamps, t hat oysters are often attached to the roots of Rhizophora trees . Evidence from these samples indicates, therefore, that deposition during th~s interval took place in a mangrove swamp environment. As mangrove swamps develop on land flooded by salt water at high tide, deposition was very close to sea level. Since the tidal range on the Atlantic coast is very low- a 6-year record ending in 1913 showed a maximum hig h water of + 1.65 ft. and an extreme low water of - 1.01 ft . (referred to mean sea level; measuremen ts taken in Colo n), with a maximum daily range of 2. 17 ft. (Rousseau, 1913)- deposition must actually have taken place very close t o mean sea level. Rhizophora pollen i& not present in the samples above about 28 ft. below current sea level ; pollen of fresh-water swamp vegetatio n suggests deposition in &wamps inland from the Rhizophora zone. During this period, deposition was undoubtedly

A. S. BA RTLETT AND E. S. BARGHOORN

PHYTOG EOGRA PHIC HISTORY OF T HE ISTHM US Of f'ANAMA

controlled d irectly by g•o undwater on the poorly d rai ned to pography, a nd thus only secondarily by the rising sea. Therefore, alth ough sea level ultimately controlled deposition in the extensive swamps which covered the Ga t un basin at this t ime, the peat samples deposited do not define sea level as precisely as does the m-angrove muck below. Pollen diagrams of cores T DS-2, T DS-4, and S L-48 ( Fig.8-10) show that the upper limit of Rhizop!tora pollen is not identical in the three cores. Rl!izop!tora pollen d isappears first in core TDS-4, then core T DS-2, and last in core SL-48. This circumstance appears, at fi rst, to imply non-correla tion of the three co res. T hat t his is not t he case, ho wever, is sho wn by two fac ts. First, several very unusual pollen types reach t heir hig hest freq uencies at the same levels. !lex, Myrica, or Ouratea pollen, each o f which is presen t in at least two of the three cores, reaches its maximum at approximately equal depths below sea level in all of the cores in which it is present. In addition, rad iocarbon d ates show good correlation between the cores. lt appears, t herefore, that during the period of time when the transition from saline to fresh water occurred, as shown by transition from mangrove to fresh-water swamp vegetatio n, the site of deposition of these three cores_must have been in the vicinity of the latitudinal saline/fresh water bo unda ry. A s thi s was determined not o nly by the surficia l drainage from the hills to the west of this site, bu t also by t he Trinidad River, which meandered O><er the sedimentary deposits in this area and repeatedly shifted its course over the years, an exact determination of the latitudinal location of this boundary at any specific time is not possible. T he fi nal transition from sa lt-water to fresh-water influence did not, however, take place in the vicinity of these cores until about 4,200 years -ago at - 28ft., as shown by Rhizoplwra pollen in core SL-48.

Shepard (1 963a) shown in Fig.5 demonstrates tha t sea-level rise as ind icated by the Ga tun basin dates is q uite consiste nt wit h data from other sta ble areas th rougho ut the world. T he Pana ma d ates tl t well within-t he range of Shepard's, with the excep tion o f several yo unger tha n 5,000 B. P., wh ich indicate a sea level somewhat lower than do his. Most of these arc of samples from peat layers, which comprise a considerable portio n of the sedimentary column from a bove about -45 ft. in cores T DS-2 and TDS-4. Altho ugh the peat is highly unconsolidated, it is probable that some compaction has occurred.

290

Sea-fepef data from the Gatw1 Basin

Of the eighteen radiocarbon dates obtained of the Gatun samples (Table I), three were rejected as having no bearing on the sea-level problem. Two of these dates, 5,980 ± 80 B.P. (UCLA- 1019) a nd 6,300 ± 150 B.P. (Lamont 753-D), were far o ut of line with younger dates from stratigrap hically lower levels from nearby cores. T he two samples, which consisted of peat, were our only samples from core T DS-8, thus making a correlation -check . with other co res by pollen content impossible. Plant microfossils in both consisted chiefly of fern spores (not Acrostichum); since no Rhizophora pollen is p resent, these samples give little indication of their relatio nship to sea level, and may not be taken as evidence of a high sea level about 6,000 years ago. The third rejected sample was dated 3, 170 ± 60 years B.P. (UCLA-1335; 43 ft. below sea level). This determination is suspect when compared with the other radiocarbon dates obtained at this level. A time/dep th graph showing eustatic sea-level change in Panama has been constructed from the remaining dates (Fig.6). Comparison with data collected b y .

291

Sea lel•e/ 35,500 B.P. The oldest (post-Tertiary) sample present in any of the Gatun basin cores stud ied is of particula r interest in that it shows a possi ble Wisconsin high-sea level. The sample, shown in Fig.6, is 162 ft. below present sea level, and has been radiocar bon dated at 35,500 ± 2,500 B.P. As the sample -conta ins a high percent of Rhizoplwn1 pollen (see Fig.?), large, heavy pollen grains, and nu merous hystrichosphaerids, it must have been deposited in or very near a mangrove swa mp, essentially at sea level. T his sample, therefore, supports ot her evidence, al ready cited, of a high sea level about 35,000 years ago, and is within the ra nge o f -225 to - 120 ft. below p resent sea level thought probable during this time by Prof. R. Be rger (personal communication, 1966). T he Gatun basin cores provide no evidence of the chrono logy of rising sea level between 35,500 and I I ,300 B.P., as th is in terval is represented in these cores by a sedimentary break. The time/depth graph of the Panama samples shows a period of very rapidly rising sea level between I I ,300 and ·8,500 B.P.; sedimentation and hence rise in sea level d uring thi s period averaged I ft. every 30 years (0.03 ft. per year). Ma ngrove vegetation at this time was apparently not very well developed, perhaps because of the very rapid ly rising sea. At the beginning of this interval, I I ,300 years ago, sea level was 158 ft. below t hat o f the p resent; this age determination is matched remarkably well by another determination from the Gulf of Panama, where sea level I I ,500 years ago was about 50 m (163 ft.) below that of the present (Golik, 1968). Bet ween 8,500 and 7,300 B.P., the ra te of rise slowed markedly, averaging about 1 ft. every 54 years (0.018 ft. per year). Sea level, therefore, apparently refl ected. the fact that continental glaciers had, by this time, retreated almost to their final postglacial bo undaries,_and temperatures had risen until they equalled those of the present. Although the occurren ce of thi s event was not contemporaneous everywhere and thus canno t be assigned a precise temporal val ue, changes in the vegetation of Europe and the northeastern United States indicate tha t by the end of Boreal time, approximately 8,50 0 years ago (Deevey and Flint, 1957), the postglacial rising temperature had reached that of the present. Sea level at that time was still a bout 40ft. below today's, indicating that t he melting of glacial ice and return of water to the oceans lagged behind the restoration of temperatures equal to those of the p resent. Mangro ve vegetation during this interval developed rapidly, reaching its maxi-

292

A . S. BARTLEIT AND E. S. BARG HOORN

mum extent during the pronounced slowing of sea-level rise wh ich followed during the interval from ca. 7,300 to 4,800 B.P., when sea level rose only about I ft. every 350 years (0.003 ft. per year). At the beginning of this interval, when sea level had risen to about -4 1 ft., peal deposition commenced in the po rtion of the Gatun basin under stud y, as shown by cores TDS-2 and TDS-4. Peat formation continued without interruptio n until approx imately 4,200- 4,500 B.P., when the rate of rise accelerated o nce more, and deposition o f peat ceased temporarily. The appa rently very slow rate of r ise during the deposition of this peat does. not reflect the postglacial warm period, or "hypsithermal interval" (Deevey and Flint, 1957) postula ted by many palynologists to have existed during this time. Mean ann ual temperat ures d uring this interval, wh ich lasted from ca. 9,000 to 2,600 B.P. (Deevey and F lint, 1957) are thought to have exceeded those of the present. Sea level at this time should, therefore, have risen mo re, rather than less rapidly if climatic inferences about this per!od are valid. The reason for the lack of correspondence between sea-level data from Pa nama and o ther regions and climatic history as postulated on the basis of inferred vegetatio nal changes is not clear at this time. The opposite conclusion, that climate was cooler during at least part of this interval, is more in accordance with the Pana!'1a data. Portions of the Gatun cores deposited after 7,300 B.P. provide significant evidence contradict ing the hypothesis that sea level rose above its present sta11d at about 6,000-4,600 B.P. a nd 4,000-3,400 B.P. (Fairbridge, 1961a). During the period from 7,300 to 3,400 B.P., an uninterrupted layer of fresh-water peat was deposited in core TDS-4. Fresh-water peat was similarly deposited in core TDS-2 from more than 7,300 B. P. to about 4,000 B.P. Vegetat ional history of the northern Gatun basin as indicated by pollen extracted from this peat shows absolutely no trace of the extreme change in edaphic conditions which would inevita bly have resulted fro m high sea levels during this interval. 1t i ~ highly improbable t hat sea water could have flooded the fresh-1-'!:ater vegetation growing in t he area to a depth of more than 40 ft. and then receded, leaving no detectable evidence of either the transgressive or regressive phase of the oscillation, a nd influencing neither the character of the vegetation no r of the sediments deposited. It should be no ted, in connection with Fairbridge's hypothesis, that such high sea levels depend on p resent sea level having been reached by about 6,000 B.P. If that were the case, subsequent fl uctuations bringing the sea above its present level by as much as 10- 15 ft. would have been, relatively speaking, mino r. H owever, if sea level 6,000 years ago was still about 40 ft. or inore below that of the present, as the bulk of t he data available indicates, such fluctuations would be quite improbable on considerations alone of the rapidity which would necessarily have characterized them. Under such circumstances, change of sea level during the Older Peron Submergence, frorri 6,000 to 4,600 B.P. would necessarily have proceeded at a rate of about one foot every 20 years (0.2 ft. per year) which is much more rapid than that even of the la teglacial, fro m about 11,000 to 8,000 years ago.

PHYTOGEOGRAPH IC HISTORY OF TH E ISTHMUS OF PANAMA

293

S ea leiâ&#x20AC;˘e/from 4,200 B.P. to present

Samples d.eposited after 4,200 B.P. also provide no indication that sea level rose above that of the presen t du ring this period. T he time/depth graph shows that the sea rose continuo usly until about 2,000 years ago, when it had probably reached its present level. This event may actually have take n place somewhat earlier, as the thick layers of peat deposited in cores TDS-2 and TD S~4 had undoubtedly experienced some autocompaction, as well as compaction caused by o verlying clays and gravels deposited by the meandering Trinidad River. After reaching its present level several tho usand years ago, the sea may have fl uctuated about this level several times. The Gatun basin data show a pronotmced change in rate of rise at about 2,100 B .P., and a subsequent recession. A similar q uickening in rate of rise at 2,100 B.P. is shown by Shepard's{l963a)d ata. The follow ing recession, which may have taken place at some time between I ,000 ancl2,000 D.P. , may be the counterpart of the Florida Emergence of Fairbridge (196 l a, etc.) which also took place at some time d uring this millenni um. It is unwarranted, however, to draw firm conclusions about the precise position of sea level du ring this relatively short inte rval, considering the fact that subsidence may have taken place and taking into accou nt also the great vertical scatter and relative paucity of dated samples from the last several millennia.

Acknowledgements

Special thanks are due to Robert H. Stewart, Geologist of the Panama Canal Company, fo r making this investigation possible by aiding in the securing of the deep cÂˇore samples, and fo r his invaluable help in the fi eld. We would also like to express our gratit ude to Professor Rainer Berger, P rofessor Willard F. Libby, and to Professor Wallace Broecker for generously providing radiocarbon dates oft he deep core samples; to D r. Loren T. Nev.ling, Curator of the Arnold Arboretum and Gray H erbaria of Harvard University and to Dr. Rolla F . Tryon, Curator of Ferns, Harvard University Herbaria, for providing access to these herbaria and for their advice in this study; to Dr. Martin Moynihan for the use of the facilities of the Canal Zone Biological Area on Barro Colorado Island; to Dr. H arold E. Moore of t he Bailey Hortorium for providing pollen of Iriartea; and for the generous fi nancial support provided by the American C hemical Society under two grants, No.PRF 947-A2; the Evolutio nary Biology Committee (Biology Department, Harvard University) under grants No. NSF G 19727, NSF GB 3167 and NSF GB7817; t he Grass-Cannon Foundation of Radcliffe College; and by Fellowships from the Faculty of Arts and Sciences, H arvard University.

294

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Kind, N. V., 1965. The radiocarbon chronology of the last glaciation and of the postglacial interval in Siberia. Int. Congr. Int. A.,·soc. Quaternary Res., 7th, Bou/der{Demer, Colo. , Abstr., 269. Kucnen, P. H., 1954. Eustatic changes of sea level. Ceo!. Mij11bouw, N. Ser. , 16: 148- 155. LeBlanc, R. J. and Bernard, H. A., 1954. Resume of Late Recent geologica l history of the Gulf Coast. Geol_ Mijnbo11w, N. Ser., 16:185-194. Leighton, M. M. and Brophy, J. A., 1966. Fa rmdale glaciation in northern Jllinois and southern Wisconsin. J. Geol., 74:478-499. Lindeman, J. C., 1953. The vegetation of t he coastal regions of Surinam, In: I. A. de Hulstcr, V. Lanjow and F. W. Ostendorf, Vegcwtion ofS11ri11am, l. Lloyd, J., 1963. Tectonic history of the south Central-American orogen. ln: 0. E. 01ilds and B.W. Beebe (Editors), Backbone of the Americas, a Symposium- Am. Assoc. Petrol. Geologists, Mem., 2:88-100. Maarleveld, J. and Vander Hammen, T., 1959. The correlalion between Upper Pleistocene pluvial and glacial stages: Geo/. Mijnbouw,N. Ser_, 21:40-45. MacDonald, D. F., 1913. Report of Geologist. In: Ann11al Report of the Isthmian Canal Commission, Appendix S. Washington, D .C., pp.565-582. MacLaren, C., 1841. The Glacial Theory of Professor Agassiz of Neuchatel. The Scotsman Office, Edinburgh, 62 pp. Marmer, H. A., 1952. Changes in sea level determined from tide observations. Conf Coast. Eng., 2nd, Proc., 62-67. Martin, P. S., 1960. Effect of Pleistocene climatic change on biotic zones near the equator. Year Book Am. Phil. Soc., 1960:265-267. Martin, P. S. and Mehringer, P. J., 1965. Pleistocene pollen analysis and biogeography of the southwest. In: H. E. Wright, J r. and D. G. F rey (Editors), The Quaremary of the United States. Princeton Univ. Press, Princeton, N.J., pp.433-45 1. McCullough, C. R., 1956. Terrain Study of the Panama Canal Zone with Specific Reference to the Ft. Sherman Area and Vicinity. Dept. Eng. Res., North Carolina State Coli., Raleigh, N.C.,266 pp. McFarlan, E. Jr., 1961. Radi6earbon dating of Late Quaternary deposits, south Louisiana. Geol. Soc. Am-,Bu/1., 72 :129-158. Milliman, J. D. and Emery, K . 0., 1968. Sea levels during the past 35,000 years. Science, 162:1 12 II 123. Muller, J _, 1959. Palynology of Recent Orinoco delta and shelf sediments. Micropa/eomology, 5 :1-32. Nevling, L. 1., Jr., 1960. Flora of Panama: Chloranthaceae, pp.121-123; Myricaceae, pp. l 28- 129; Corylaccac, pp.l33-1 34. Ann. Mo. Bot. Gard., 47. Newell, N . D. and Bloom, A. L., 1970. The reef fla t and " two-meter eustatic terrace" of some Pacific atolls. Geol. Soc. Am., Bull., 81:1881-1894. Pearson, F. J., Jr., Davis, E. M. and Tamers, M .A., 1966. University of Texas radiocarbon dates IV. Radiocarbon, 8:453-466. Pearson, F. J., Jr. , Davis, E. M., Tamers, M. A. and J ohnston, R. W., 1965. University of Texas radiocarbon dates Ill. Radiocarbon, 7:296-314. Penck, A., 1882. Geogr. Ges. Miinchen, Jalrrb., 7:29. P unt, W., 1962. Pollen Morphology of tire Euphorbiaceae with Special Reference to Taxonomy. North· Holland, Amsterdam, 116 pp. Redfield, A. C. and Rubin, M., 1962. The age of salt marsh peat and its rela lion to recent changes in sea level at Barnstable, Massachusetts. Proc. Nat/. Acad. Sci., 48:1728-1735. Richmond, G. M., 1965. Glaciations of the Rocky Mountains. In: H . E. Wright, Jr. and D. G. Frey (Editors), Tire Q11atemary of the United States. Princeton Univ_Press, Pr inceton, N.J., pp.217-

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Robyns, A., 1964. Flora of Panama. Tiliaceae, pp.l-35; Bombacaceae, pp.37-68; Sterculiaeeae, pp_69-107. Ann. Mo. Bot. Gard., 51. Rousseau, H. H., 1913. Construction and Engineering Division. In: Annual Report of the Isthmian Canal Commission. Isthmian Cana l Commission, Washington, D.C., Appendix F: 193-254. Schery, R. W., 1942. A few facts concerning the flora of Panama. Chronica Botanica 7:77-79. Schofield, J. C., 1960. Sea-level fluctuations during the past four thousand years. Nature, 185:836. Scholl, D - W. and Stuiver, M., 1965. Record of sea-level changes in southern Florida during the last 4,400 years. lilt. Congr.lnt. Assoc. Quatemary Res., 7th, Boulder/Denver, Colo., Abstr., 412.

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Chapter 8

History of the Arborescent Temperate Element in the Northern Latin American Biota1 ALAN GRAHAM

Department of Biological Sciences, Kem State University, Kent, Ohio ( U.S.A.)

Summary Recent palynological studies on Cenozoic.deposits in Veracruz reveal a distinct and diverse arborescent temperate community, with elements common to eastern United States, already present in eastern Mexico by Middle Miocene times. Collective data on the history of temperate trees and shr-ubs throughout nort hern Latin America demonstrate a progressive southward migration, with pollen of fou1 teen temperate tree genera present in sout heastern United States during the Eocene while only three arc recorded from northern South America and not until the latest Cenozoic. Pollen of Abies, Alnus, Betula, Carya, Castanea, Celtis, Fagus, Juglans, Liquidambar, Liriodendron, Myrica, Nyssa, Tilia and Ulmus are present in the Eocene Wilcox and associated floras of the Mississippi Embayment. Ten of these (A bies, Picea, Alnus, Celtis, Fagus, Juglans, Liquidambar, Myrica, Populus and Ulmus) reached southern Mexico by the Middle Miocene but a re absent in older sediments. During the same period (Miocene) only three genera (Alnus, Jug!ans, Myrica) are recorded for Central America (Panama), and are absent in p re-Miocene assemblages. I n northern South America these same th ree genera are firs t encountereq in deposits of the latest Pliocene, a nd do not become abundant u nt il the Pleistocene.

Introduction Along the eastern escarpment of the Mexican Plateau, extending from Tamaulipassouthward through San Luis P otosi, Hidalgo, Puebla, Veracruz, Oaxaca, Chiapas and into G uatemala, is a disjunct series of communities characterized by temperate trees and shrubs that also occur in eastern United States. T hese plants are absent in the intervening desert regions of northern Mexico and south Texas, and withit1 Latin 1

Research for this study was supported by NSF grants GB- 5671 and 11862. Portions of the paper were presented at the 3rd International Conference on Palynology, Novosibirsk, U.S.S.R. (1971; cf. Abstracts and Proceedings). T he author gratefully acknowledges the suggestions of Dr. Arturo Gomez Pompa, particularly during a brief visit to the Liquidambar forests in Veracruz, 1971, and Drs. A. J. Sharp, Lorin N evling and especially Carroll E. Wood for comments on the list of plants presented in Table I.

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AR BORESCENT TEMPERA'f-E..H£M ENT ·IN·NORTH.. t 'A'flN "AM ER'!CA'............3{)3............

America arc usually fa una as-iselatcd stand s of small populati ons. Some occu r most commonly as isolated individuals (e.g., Jugla11.1· pyriformis), whi le the scattered but widespread range of others provides evidence of communitie s once occupying extensive a reas of the temperate Latin American landscape (e.g., Liquidambar macro-

phy/la). The arborescent temperate element is most extensive and d iverse in the states of Veracruz and portions of Puebla, Hidalgo, and Chiapas. To the north mesic habitats decrease in extent and to the sout h competition from the tall evergreen selva becomes more intense. The no rthernmost Mexican stations for temperate species d isjunct from eastern United States are in the Sierra de Cucharas (S ierra de Guatemala, Tamaulipas in Miranda and Sharp, 1950, footnote, p.325 ; Hernandez et a!., 1951), and in the Xilitla region of southern San Luis Potosi (Miranda and Sharp, 1950). At the former site sixteen genera are listed, including Taxus globosa, Acer skurchii, Carpinus carolini-

ana, Cercis canadensis, Fagus mexicana, Hamamelis l'irginiana, Liquidambar macrophyfla, Magnolia scltiedeana, Prunus serafina, Rhamnus caro/iniana, and species of Carya, Comus, Diospyros, Jug/am·, Morus, and Ti/ia. At Xilitla Liquidambar is the only woody temperate d isjunct. At the southern terminus of its _range (northern South America) this element is represented by on ly three genera (Alnus, Juglans, and Myrica ). By comparison, fifty-three genera are found in the Veracruz-Pu ebla-Hidalgo reg ion (see Table I). The flori stic relationship between temperate biotas of eastern United States and eastern Mexico was early recognized by Watson (189 1), and subsequently investigated by Fernald (1931), Sharp (1948, 1950, 1951, 1952, 1953, 1966), Miranda and Sharp ( 1950), and Dressler ( 1954). The .southward continuation of the temperate community into Guatemala has been noted by Steyermark (1950; for revision of Juglandacea e, see Williams and Molina, 1970). H owever, the lack of detailed ecological-floristic data for eastern Mexico, comparative biosystematic studies on the taxa involved, and the complete absence of any relevant paleobotanical information has hindered an adequate understandi ng of the nature and origin of the assemblages. Recently, Gomez Pompa (1966, and Chapter 4 this book) and his associates (Leon Cazares, 1963; Gomez Pompa et al. , 1964; Leon Cazares and Gomez Pompa, 1970; Gomez Pompa and Leon Cazares, 1970; Gomez Pompa and Nevli ng, 1970) have provided important information on the composition and ecology of the Veracruz fl ora. Garcia ( 1970) has summarized the climates as part of the Flora Veracruz Project, and paleobotanic al studies have been initiated on some Miocene deposits near Coatzacoalcos (Graham, unpublished data). Collectively these modern floristic and paleobotanical investigations are beginning to reveal something of the arborescent temperate element and its history in Latin America.

Origin of the eastern United States-eastern Mexican floristic relationship

Earlier studies Simi larity in vegetatio n between two d isjunct regions may result from gradual migration in response to climatic change and fl uctuating physical barriers, and/or abrupt long-distant transport. Most communitie s include components representing both types of dispersal. Thus propagulcs from plants of eastern United States have probably been introduced periodically into eastern Mexico during various epochs of the Tertiary. The introductio n of other species, notably those lacking efficient means of long-distant dispersal, has undoubtedly been fa cilitated by changi ng Cenozoic environment s. The paleobotanic al and geological data to be discussed are applicable to the latter category of plant disj unctions. Almost every segment of geol ogic time since the Cretaceous has been proposed as the principal time of introduction of northern elements into Latin America. McVaugh (1952) gives t he Cretaceous and Early Tertiary as possible initial phases o f introduction; Steyermark (1950) lists the Early Tertiary; Sharp {1953), the Pliocene and Pleistocene; and Deevey (1949) and Dressler (1954) the Pleistocene. The most widely d iscussed epoch for interchange between eastern United States and eastern Mexico is the Pleistocene. This is based in part on reports by Brown (1938), Potzger and Tharp ( 1943, 1947, 1954), and D avis ( 1946) d escribing pollen and megafossils of boreal conifers (Abies, Picea, Larix, Thuja) from late-glacial and postglacial deposits along the United States Gulf Coast. The implication of these reports for Pleistocene biogeography has been summarized by Deevey ( 1949). Colledively they suggest that if during the Pleistocene a boreal coniferous forest existed as far south as the G ulf Coast, elements of the mixed deciduous hardwood forest may have migrated into refugia in eastern Mexico. The time of origin for these floral and faunal affinities is inexorably involved with the problem of the effect of Pleistocene climatic change on the biotas of southern United States. Whitehead and Barghoorn (1 962), Whitehead (1965, 1967), and Watts (1 970, 1971) have demonstrated changes in the composition o f plant communities in the southeast d uring the Pleistocene as revealed by pollen diagrams, a nd evidence f.or the existence of northern elements (e.g., Pinus banksiana) growing considerably south of their present range. Vuilleumier (1971) has surveyed modern flori stic and faunal evidence and paleontological data in South America and conclud es that even the p resummed stable biotas of equato rial regions (e.g., the tropical lowlands of t he Amazon Basin) were significantly affected by Pleistocene climatic changes. Bartlett and Barghoorn (Chapter 7, p.203) also note that: " Although vegetational changes discernable in the pollen sequences from these sediments are caused chiefly by alterat ion of edaphic conditions owing to the influence of rising sea level, the effect of postglacial climatic amelioration is also evident." Conversely, some of the early data on which a Pleistocene interchange was based

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have been questioned. For example, in a restudy of the Texas material (Graham and Heimsch, 1960), the presence of Abies could not be verified and the percentage of Picea pollen in the restudy was 2 % rather than the II %origina)ly reported. Comparable results have also been obtained recently by Bryant (personal communication, t 971) for other Texas peat deposit~. The possibility that Larix and Thuja megafossils in Louisiana (Brown, 1938) could be drift incorporated du ring times of flood has not been adequately investigated. A date for the deposits, "presumed to date fro m Wisconsin time, yielded, on fecollection, a radiocarbon date of 7,240 years ago" (Wright, 1971}. The Picea pollen from Florida (Davis, 1946) was neither described nor fig ured, but Watts (1969, 1971 } has found traces of spruce pollen in lake sediments from central Florida. Picea rubens Sarg. presently grows in southernmost Tennessee and N orth Carolina. Pie! (1965) has reported Picea pollen in Recent Mississippi River delta deposits and thi s has implications regarding the late-glacial and postglacial d i~tr ibutio n of spruce pollen in periglacial sediments. Certainly there is the possibility of Picea extending its range south along the Mississippi and other river valleys as a result of cold-air drainage, such that a few pollen grains could be incorporated into periglacial sediments. This would explain the small perc<:ntages of Picea pollen confi ned to the lower levels of the Texas bogs without implying the presence of an extensive boreal coniferous fores t along the Gulf Coast. Pollen diagrams which show the greatest modification of vegetation during the Pleistocene are in or adjacent to regions of significant physiographic relief (viz., the Appalachians) where such effects would be expected. Even in the diagram of Watts (1970), where pollen and needles of the northern Pinus banksiana Lamb. a re reported in Pleistocene deposi ts in Georgia, the deciduous hardwoods are represented. The fo llowing were found at levels below those dated at 20,100 Âą 240 years. B.P.: Alm1s, Betula, Carya, Fagus, Fraxinus, Juglans, Myrica, Nyssa, Ostrya type, Platanus, Quercus, Salix, and Ulmus. The presence of Pinus banksiana in Georgia is evidence that northern plants were introduced into southeastern United States during the Pleistocene. Fluctuations in the relative abundance of indigenous temperate genera further suggest the southeastern flora was influenced by Pleistocene climatic changes. However, pollen of broad-leaf deciduous genera persist throughout the pollen diagrams, and this is difficult to reconcile with any concept of near-complete replacement of the eastern deciduous forest by boreal elements. A conservative view of vegetational history in the southeast would be a community definitely influenced by fl uctuating Pleistocene environments (e.g., in the relative abundance and local Âˇdistribution of ecotypic components, and with t he introduction of more northern elements as "target areas" for the propagules of these plants expanded), but a community still retaining the general a~pect and composition of the deciduous forest in a regional sense. Along the suggested coastal plain migration route of the deciduous forest into Mexico, however, physiographic relief did not serve as a supplement to climatic change, and consequently alteration of the vegetation would be proportionately less. The unresolved problem is not solely whether the vegetation of southeastern

ARBORESCENT TEM PERATE ELEMENT IN NORTH LATIN AMERICA

305

United States wa~ sign ificantly innuenced by Pleistocene environmental changes, but whether these innucnccs extended sufficiently westward to allow temp_eratc elemen ts of the eastern. deciduous forest to transgress the present desert barrier in sou th Texas and northern Mexico. As Wright (197 1) has noted, very little is known about fullglacia l vegetationa l history in the south. A difficulty to envisioning Pleistocene interchange between southeastern United States and eastern Mexico has been raised by Martin and Harrell (1957). They have shown affinities among amphibians in these areas are at the generic level, the species in the two regions generally being different. This implies a long period of separation, and Martii1 and Harrell (1957) favor the Tertiary rather than the Pleistocene as the time of continuity between the biotas. Unfortunately the taxonomic level at wh ich the floral relationship is expressed cannot presently be used to evaluate a Pleistocene versus an older Tertiary origin. [n Table I, sixty plants are listed that have been reported as part of the eastern United States-eastern Mexican floristic pattern. With few exceptions none of these have received critical taxonomic study with particular reference to their disjunct occurrence. Study of variat ion in the Mexican populations compared with that in their eastern United States counterparts, and cytological data (chromosome numbers) for each taxon in the two regions would provide a more sound taxonomic base for phytogeographic interpre tat i on~. A survey of the literature reveals that of the sixty trees and shrubs listed, twenty-one (35 %) are regarded by at least some authors as identical, twelve (20%) are vicariads, and twenty-seven (45%) are considered distinct, or a simi lar species is not known or is not listed. Although these figures suggest that about 2/3 of the trees and shrubs common to eastern United State~ and eastern Mexico have had sufficient time to speciate into distinct taxa, the lack of critical comparative taxonomic data makes the figures of limited use in distinguishing between Pleistocene and Tertiary introductions. Another factor of importance is that continuity between the temperate communities implies the present desert barrier was eliminated or modified. If a Pleistocene interchange is proposed, this acknowledges at least the possibility of one to fo ur migrations, with concomitant disruptions of the desert barrier, during the last 1-2 million years. There are difficulties inherent in envisioning a mixed deciduous hardwood fores t in the present desert regions of Texas and northern Mexico in relatively recent time. Edaphic factors would preclude the community from growing on the limestone and sandstone gravel and rubble that presently constitutes much of the soil in the area. Yet on the basis of numerous well cores drilled in this petroleum-rich region of the Texas Gulf Coast there is no evidence of buried soil horizons of the rich podzol type. Drainage systems that could serve as migration routes via gallery forests trend at right angles to the required direction of migration rather than paralleling the Texas coast. Another difficulty is that many desert plants show evolutionary modification to the xeric environment. Morphological features such as sunken stomata, thickened

306

A. GRAHAM

ARBORESCE NT TEMPERATE ELEMENT IN NO RTH LATIN AMERl CA

TABLE 1 Arborescent (tree and shrub) genera common to eastern United Stutes and caslern Mexico. (Modified from Miranda and Sharp (1950), Hernandez et al. (1951), Dressler (1954), and Gomez Pompa (Chapter 4, this book) ·

Jdenlical species Pinus strobus L. (var. chiapensis Martinez in Mexico) Acer negrmdo L.1 • Ascymm hypericoides L. var. hypericoides(cf. Adams. 1957)' Carpinus caroliniana Wah. Carya i/linoensis (Wang.) K. Koch' C. myristiciformis (Michx. f.) Nutt.' C. o••ota (Mill.) K. Koch' Cercis canadensis L.' Comus florida L. subsp. urbinicma (Rose) Wang. Erythrina herbacea L. Fagusgrmulifolia Ehrh.' Hamamelis virginiana L.1 flex vomitoria A it. (var. c/riapensis Sharp) Nyssa sylvalica Marsh Ostrya virginiana (Mill.) K. Koch Osmantlws americanus (L.) Benth. and Hook. (cf. Wilson and Wood, 1959)' Pt'tl/111.\' serotina Ehrh. subsp. serotina (cf. McVaugh, 1952) Rlwmnus betulifolia Greene (cf. Brizicky, 1964) Smilax glauco Walt. S. hispida Muhl. ex Torr. Staphylea trifolia L. (includes S. pringlei S. Wats.; cf. Spongbcrg, 1971) Species pairs Mexican species Taxodiummucronatwn Tenore Taxus globosa Schlecht. 10 Acer skutchii Rehder llliciumf/oridanum Ellisll Leucotltoe mexicona {Hems!.) Small Liquidambar macrophylla Oerst." Magnolia dealbata Zucc.13 M. schiedeana Schlecht." Myrica pringlei Greenm.11 Sambucus mexicana Presl. u Styrax glabrescens Benth. Ti/ia longipes Bush"

U. S. species T. distichttm (L.) Richard T. jforidaua Nutt. A. saccharum Marsh I . mexicqmmr A. C. Smith L. populifolia (Lam.) Dippel L. styracijfua L. M. macrophylla Michx. M. grandif/ora L. M. cerifera L. S. canadensis L. S. grandifolia Ait. T. heterophyl/a Vent

Distinct Mexican species Abies religiosa (HBK.) Schlecht. Pinus (many species: P.ltartwegii Lind!., P. momezumae Lamb., P. pseudostrobus Lind!., P. rudis End!., P. teocote Cham. and Schlecht., etc.) Alnus arguta (Schlecht.) Spach. Celtis iguanaea (Jacq.) Sarg. 2 Cletltra quercifo/ia Lindl. (five other species occur in Veracruz; L. I. Nevling, personal communication, 1971) 16 Comus excelsa HBK., C. disci/fora DC. Crataegus pubescens (HBK.) Steud. Diospyros riojae G6mez Pompa, D. digyna Jacq." Fraxinus schiedeana Schlecllt. and Cham. Gaultheria acuminata Schlecht. and Cham., G. hida/gensis Loesen., G. hirtifolia Benth.. G. odorata Willd. 17

307

TABLE I (COIIIilllletl}

Jug/mrs pyriformis Licbm. (and olhers; cf. Manning, 1957) Lilsea glauccscens H BK. J'ersea americatta Mill., P. chctmi>·sonis Mcz., P. cinems,·e11s Blake, P. schiedeana Necs. Platalltts cltiapensis Standi., P. lintlenialla Mart. a nd Gal." Populus mexicana Wcs. Potentilla riclwrdii Lchm. Prw1us brachybotrya Zucc., P. capu/i Cav. ( = P. ,·erotino subsp. capuli), P. rlwmnoides Koehne, P. samydoides Schlecht., P. tetmdemia Koehne Quercus ~many species: Q. candicans Nee, Q. castanea Nee, Q. crussifolia Humb. and Bonpl., Q. mexicana Humb. and Bonpl., Q. oleoides Cham. and Schlecht., Q. xalapensis Humb. and Bonpl., etc.) Rhamnus capraefolia Schlecht., R. micropltylla Willd. Salix taxi/olio HBK. (and other species) Sapimlus saponaria L." Symplocos coccinea Humb. and Bon pl." .Ulmus mexicana Liebm.•• Vaccinium conferlwn HBK., V. /eucanthw11Cham. and Schlecht. (subg. Batodendron. cf. V. a•·boreum) Vemonia patens HBK. (plus ten other species in Veracruz; L. !. Nevling, personal communication, 1971) Vibumum acutifolillm Benth., V. microcarpum Schlecht. and Cham., V.micropftyllum(Oerst.) Hems!., V. t iliaefolium (Oerst.) Hems!. Zanthoxylum caribaeum Lam., Z. kel/ermtmii Wilson. Z. elegantissimum (Engl.) Wilson, Z. procerrm 1 Donn. Sm. 1 Disj unction not pronounced; almost transcont inental in range. • Not a strict eastern United States-eastern Mexican disjunct; viz., occurs outside these areas, as in the West Indies. 'Disjunction not pronounced; occurs from northern United States into east Texas, Coahuila, Nuevo Leon and south to Jalisco, Hidalgo and Oaxaca. • South Carolina to east Texas, Nuevo Leon and Tamaulipas. For treatment of Carya, see Elias ( 1972). ' Frequently listed as C. mexicana Engelm., but t reated in the recent literature as a synonym of C. ova/a. 'Hopkins (1942) recognizes four varieties, three of which (typica, mexicana, texensis) overlap in Texas and extend into Mexico (var. mexicana is the most southern, cf. map in Hopkins (1942), p.l97). The other, var. occidentalis, is western U.S. Thus the range of the species is nearly continuous between eastern U.S. and eastern Mexico and is not a strict disjunct. 'The Mexican species was described as F. mexicaua Martinez. It is usually treated as F. grandifolia var. mexicana. The taxa are very close, if not identical (cf. Little, 1965). 8 Originally described by Standley from Nuevo Leon as H. mexicana, but generally regarded as a synonym of H. virgiuiaua. 'Green (1958) treats the Mexican plants as dilferent varieties. 10 May not be a species pair; another (T. b•·evifolia Nutt.) occurs in western U.S. 11 Very closely related; possibly identical. "Also treates as L. styracif/ua var. mexicana Oerst. 13 Regarded by A. J. Sharp, C. E. Wood (personal communication, 1972), and other as t he same species. "Both species are high polypiids (2n = 114); may not be a species pair. "T. mexicana Schlecht. fide Jones (1968). Miranda and Sharp (1950) cite T.lteteropltylla as similar to T. longipes. Jones (1968) lists T. caroliniana Mill. The taxonomic relationships are unclear. 11 Listed in the literature but not closely related to species in eastern U.S. 17 These Veracruz species belong to Sect. Brossaeopsis, also represented in western U.S.; the two species in eastern U.S. belong to Sect..Gaultheri a. · 18 Primarily tropical; cf. Brizicky (1963). 11 Generically disjunct, but the eastern U.S. species are more closely related to Asiatic ones. 10 Represents a monotypic section of the genus; viz., only distantly related to species in eastern U.S.

A. GRAHA M

ARBOR ESCENT TEMPERATE ELEMENT JN NORT H LATIN AMERICA

cu ticle, extensive periderm development, microphyllous and sclerophyllous leaves, replacement of leaves by spines, photosynthetic cortical tissue, and succulence; physiological features such as adaptatiops to high salt concentrations, and vernalization ; and ecological features such as development of myrmccophily and pollination factors related to desert-inhabiting vectors are products of long-term evoluti on and this fact cannot be disregarded in suggesting a Pleistocene origin for the United States-Mexican discontinuity in tempenite biotas. From an objective assessment of ava ilable information, it appears there is no incontrovertible evidence favoring either the Pleistocene or the Tertiary as the principal time of floral interchange between eastern United States and eastern Mexico. If other complicating factors, such as differences in evol utionary rates among the taxa involved, vegetational changes induced by lowering of sea-level (e.g., water tables) rather than climatic changes (Watts, 1969, 1971), and the possibil ity of long-distant transport du ring the ~ertiary, Pleistocene and Recent times are considered, concl usions become even more speculative. Recently, however, pollen stud ies on Cenozoic deposits in eastern Mexico have provided some additional information relevant to the problem of a Pleistocene versus Tertiary origin.

PLATE I

308

309

New data from the Miocene Paraje Solo Formation, Veracruz, Mexico In the southern part of the state of Veracruz, near Coatzacoalcos a series of lignites are exposed as part of the Paraje Solo Formation. These sed iments are regarded by geologists of the Pemex Corporation, Coatzacoalcos and by Salas (personal communication, 1967) as Middle Miocene in age. Approximately 300 morphological types of pollen and spores have been recovered, and among these are pollen of several temperate genera belonging to the eastern United States-eastern Mexican complex. Fossil pollen of Abies (Plate I, I) is present in small amounts (less than I %) in most samples. In the modern flora of Veracruz the gen us is represented by A. religiosa (HBK.)Schlecht. Fossil pollen of Picea(Piate I,2)ispresentbutrareinallsamples. Spruce does not occur in Veracruz, but is k nown from Nuevo Leon (P.mexicana Martinez) and Chihuahua and Durango (P. chihuahuana Martinez; cf. Gordon, 1968). A few grains of Liquidambar (_Plate I, 3) have been recovered, together with two common associates in the Liquidambar forest, Quercus (Plate I, 5)1 and Cyathea. Pollen of Fagus (Plate I, 4), Myrica (Plate I, 6)2, Juglans (Plate I, 7), Ulmus (Plate T, 8, 9), Populus (Plate I, 10), Celtis (Plate I, II, 12), and Alnus (Plate I, 13, 14) are in the Paraje Solo sediments. All of these occur as part of the modern temperate flora of eastern Mexico. Both Quercus and /lex occur in the modern and fossil Larin American floras discussed. Their presence is noted, but it is not possible to distinguish tropical versus temperate species of rhese genera on the basis of pollen morphology. 2 Myrica has recently been found as part of the tropical lowland vegetation in Veracruz (G6mez Pompa, personal communication, 1971) as well as in middle altitude temperate communities. This genus, like Quercus and Ilex may not be an appropriate example of similarities in temperate communiries between eastern United States and eastern Mexico.

'â&#x20AC;˘

.Âˇ= 8~ . .; ..._... ~,:. ~;..... -

---'--

.10

Pollen of temperate genera from the Miocene Paraje Solo Formation, Veracruz, Mexico. L

2. 3.

Abies. Picea. Liquidambar .

4. 5. 6.

Fagus. Quercus. Myrica.

7. 8, 9. 10.

Jugla11s. Ulmus. Populus.

Jl , l 2. Celtis. 13, 14. Alnus.

310

A. GRAHAM

These paleobotanical stud ies demonstrate that a disti nct and diverse arborescent temperate element was already present in eastern Mexico by Middle Miocene time. Further research will be necessary to refine the time or times of introd uctio n of the arborescent temperate element into the eastern Mexican flora, the pathway of migration, and the sign ificance of long-distant tra nsport. Jf the results of these stud ies suggest further difficulties in accepting the Pleistocene as the. principal period for flor istic continuity, the Veracruz data show that at least it is not necessary to confine theories on the origin of this biotic relat ionship to the Late Cenozoic. A tentative evaluation of the data, together with that previously discussed for the Pleistocene flora o f southeastern United States, presently favo rs a Tertiary origin for flo ri stic sim ilarities between eastern United States and eastern Mex ico dating back at least to Middle Miocene times.

ARBORESCENT TEMPERATE EL EMENT IN NORTH L ATI N AMERICA SQUT-HEASTERN UNITED STATES EOCENE

OLIGOCENE

MIOCENE

~~~

SIMOJOVELNONE

!!!i"!U ABIES

PARAJE SOLO-

ii!lli~ ALNUS

s!'ij CASTANEA

REC ENT

LAS CASCAOAS, CULEBRA, LA BOCANONE GATUN 3 GENERA

SAN MATEO

!l~~]

mB ABIES PICE A ALNUS

ill!~ JUGLANS

CELTIS

~~ LI OUIDAMBAR

FAGUS

~]l~j MYRICA

JUGLANS

n:::::: LIR IOOENORON

LIOIJ IDAMBAR

!!!in! NYSS A ~!!j! TILl A

POPUL US

~~ULMUS

LOS CUERVO$, MIRADOR- NONE

!11~]

:i'~iยง BETULA

~~CARYA

PLEISTOCENE

NORTHERN SOUTH AMERICA

WILCOX 14 GENERA

1!! CELTIS

The Miocene pollen assem blages from Veracruz are part of a study on vegetational history in northern Latin America. Plant microfossils have also been reco vered from Panama in the Eocene Gatuncillo Formation, ttie Oligo-Miocene Culebra, Cucaracha and La Boca Formations, and the Miocene Gatun Formation. Po llen fro m Pleistocene sediments in the Gatun Basin, Panama has been studied by Bartlett (1967; a nd Chapter 7 in t his book), and Langenheim et al. (1967) have recovered microfossils fro m the Oligo-Miocene Simojovel Group, Chiapas, Mexico. In northern South America (Colombia, the Guianas) investigations by Van der Hammen (1961a,b, 1962, 1963), Gonzalez Guzman (1967), Wymstra ( 1971) and others include sediments ranging in age from Cretaceous to Recent. fn each of t hese assemblages a number of unidentified palynomorp hs remain, usually representing less common memb~r s of the tropical evergreen selvas. Pollen o f temperate genera, however, are familiar to most palynologists and consequently data on the history of this element is more complete than for tropical species. If these localities are ari"a nged by age in a north-south sequence, there emerges a record of progressive southward introduction of arborescent temperate elements into Latin America (Fig. I). The collective results of recent studies on Eocene floras in southeastern United States (Gray, 1960; Dilcher, 1963 ; Elsik, 1968) reveal the presence of fourteen temperate tree genera: Abies, Alnus, Betula, Carya, Castanea, Celtis, Fagus, Juglans, Liquidnmbar, Liriodendron, Myrica, Nyssa, Tilia, and Ulmus. To the south in Chiapas, Mexico pollen of arborescent temperate genera are absent in the Oligo-Miocene Simojovel Group (Langenheim et al., 1967) but occur in the younger Middle Miocene Paraje Solo Formation (Fig. I ). Ten genera have been identified: Abies, Picea, Alnus, Celtis. Fagus, Juglans, Liquidambar, Myrica, Populus, and Ulmus.

PANAMA

GATUNCILLONONE

PLIOCENE

Progressive southward introduction of the arborescent temperate element into the Latin American biota

MEXICO

31t

3 GENERA

MYRICA

ULMUS

MYRICA

Fig. I. T he occurrence of pollen of arborescen t tempcrale elements in Cenozoic deposits in northern Latin America . Sources. Wilcox: Dilcher ( t963), Elsik (1968), Gray (1960); Simojovet: Langenheim et al. (1967); ParajeSolo, Gatuncitlo, Las Cascadas, Culcbra, La Boca: Graham {this report and unpublished data); Los Cuervos, Mirador (Colombia): Gonzalez Guzman (1967); San Mateo: data of lina Balseiro (Dept. Zulia, Venezuela ; Vander H ammen, personal communication, 1972).

F urther to the south well preserved fossi l microfossils have been recovered from a surface outcrop o f the- Eocene Gatuncillo Formation, the Oligo-Miocene Culebra, Cucaracha an d La Boca Formations exposed along the Gaillard Cu t in the Canal Zone, and from well cores in the M iocene Gatun Formation, Gatun Basin, Panama. Temperate pollen types are absent in the Eocene and Oligo-Miocene sedimen ts, but a few grains of three genera are found in the Gatun Formatio n: Alnus, Juglans, and Myrica. In northern South A merica the collective results of studies by Vander Hammen and his associates have demonstrated that pollen of temperate trees first appear in small quantities in the uppermost Pliocene, and do not become common until the Pleistocene. In South America these genera are Alnus, Juglans, and Myrica. A considerable amount of additional evidence is needed to evaluate the gradual and continuous southward migration of temperate species during the Cenozoic implied by the scattered and incomplete data currently available. The presence of Alnus, Juglans, and My rica in Panama as early as the Miocene, while introductio n

A. GRAHAM

ARBOR ESCENT T E MPER ATE ELEM ENT IN NORTH LAT IN AMERICA

into northern South America was delayed unti l the Plio- Pleistocene, is proba bly related to the orogenic history of the Isth mian region. Paleobotanical stud ies in Panama have only recently been init iated (Ba rtlett, 1967, and Chapter 7 in th is book; G raham, unpublished data) and results fro m the Terti ary studies are still tentative. T he stratigraphic position and correlation of pollen-bearing units about the Caribbean basin is also subject to revision. The presence, however, of fou rteen arborescent temperate gen~ra in the Eocene of so utheastern Un ited States with a progressive decrease in numbers and later appearance to the south does warrant consideration in newly developing concep ts on the history of Latin American plant co mmunities.

G reen, P. S., 1958. A monograph ic revision of Osma/111111.\' in Asia a nd America. Notes Bot. Card. Edinb. , 22:439- 542. Hernandez, E., Crum, 1-1., Fox, W. 13. a nd Sha rp, A. J., 1951 . A unique vegeta tional area in T amaulipas. Bull. Torrey !Jot . Club, 78 :458-463. . Hopkins, M ., 1942. Ccrcis in North America . Rlwtlora, 44 : 193- 21 t. Jones, G . N., 1968. Taxonomy of American Specie.> of Liuden ( Tilia) . ( 11/inoi•· Bioi. Mo11ogr. 39), Univ. Illinois Press, Urbana, Ill., 156 pp. Langenheim, J. B ., Hackner, B. L. and Bartlett, A., 1967. Mangrove pollen a t the depositiona l site of Oligo-Miocene amber from Chiapas, Mexico. Bot. Mus. Leaflets, Han•ard Unit•., 21:289-324. Leon Cazares, J . M ., 1963. Plano de Vegetacion del S ureste del Estado de Veracruz. Thesis, Univ. Nal. A uton. Mexico, Mexico, D.F., 40 pp. Leon Cazares, J. M. and Gomez Po mpa, A., 1970. La vegetacion del sureste de Veracru z. Bot. Esp. Ins /. Nal.luo•. For. Mex., 5 :1 3- 48. · Little, E. L. , 1965. Mexican Beech , a va riety o f Fagusgrandifolia. Castanea, 30 :167- 170. Manning, W. E ., 1957 . The genus Jug/am· in Mexico and Central America . ). Amold Arboretum, 38 :121-150 . Martin , P. S. and H arrell, B. E., 1957. T he Pleistocene history o f temperate biotas in Mexico and eastern United States. Ecology, 38:468-480. · McVaugh , R ., 1952. Suggested phylogeny of Prmws set·otina and other wide-ranging phylads in No rth America. Brillonia, 7:3 17- 346. · M iranda, F. and Sharp, A. J., 1950. Characteristics of the vegetation in certa in temperate regions of eastern Mexico. Ecology, 3 1 :313- 333. Piel, K. M ., 1965. Palynology of Some Recent Sediments from the Mis;'iJsippi Riow Delta. Thesis, T ulane Un iv., New Orleans, La ., 461 pp . (unpublished). Po tzger, J . E. and T harp, B. C., 1943. Pollen record o f Canadian spruce a nd fi r from a Texas b og. Science, 98:585- 586. Potzger, J . E. and Tharp, B. C., 1947. Pollen profile from a Texas bog. Ecology, 28:274- 280. Potzger, J. E. and T harp, B. C., 1954. Pollen study o f two bogs in Texas. Ecology, 35:462-466. Sharp, A. J., 1948. Some fungi common to the highla nds of Mexico a nd Guatemala and eastern United States. Myco/ogia, 40:499-502. Sharp, A. J., 1950. A new variety of flex vomitoria from southern Mexico. Bot. Mus. Leaflets, Harvard Unit•., 14: 107- 108. Sharp, A. J., 1951. The relation of t he Eocene Wilcox ftora to some m odern floras. Evolution, 5:1-5. Shar p, A. J., 1952. Too•ara in Mexico. Rhodora, 54:305- 306. Sharp, A. J., 1953. N otes on t he flora o f Mexico: world distri bu tion of t he woody dicotyledonous families a nd t he origin of the modern vegeta tion . J. Ecol., 41 :314-380. Sharp, A. J., 1966. Some aspects o f Mex ican ph ytogeography. Ciencia, 24:229- 232. Spongbcrg, S., 197 1. T he Staphyleaceae in the southeastern U nited States. J. Amold Arboretum, 52: 196-203. Steyermark, J . A., 1950. Flora of G uatemala. Ecology, 3 1:368-372. Van der H ammen, T ., 1961a. T he Quaternary climatic changes of northern South America. Ann. N.Y. A cad. Sci., 95:676- 683. Van der H ammen , T ., 1961b. Paleocene sediments in British Guiana and Surinam. Geol. Mijnbouw, 40 :231 - 232. Van der H a m men, T ., 1962. Palino logia de Ia region de " Laguna de Los Bobos", histo ria de su clima, vegetacion y agricu ltura d urante los ultimos 5,000 anos. Rev. A cad. Columbiana, I I :359361. '{an der H ammen, T ., 1963. A palynological st udy o n the Quaternary of Bri tish Guiana. Leidse Ceo/. Meded., 29:125- 180. Vuilleumier, B.S., 1971. Pleistocene changes in the fauna a nd flora of South America. Science, 173: 711-780. Watson , S., l 89 1. The relation of the Mexican ftora to that of the U nited States. Proc. Am. Assoc. Adv. Sci., 39:291-292. Wa tts, W. A ., 1969. A pollen diagram from M ud Lake, Marion County, North-Central F lorida. Bull. Geol. Soc. Am., 80 :631- 642. Watts, W. A ., 1970 . The full-glacial vegetatio n of n orth western G eo rgia. Ecology, 5 1:17-33.

312

References Adams, W. P., 1957. A revision of the genus Ascyrum (Hypericaceae). Rlwdora, 59: 73- 95. Bartlett, A., 1967. Palynological Studies ofCatwt Basiu, Panama. T hesis, Harvard Un iv., Camb ridge, 125 pp. Brizicky, G. K., 1963. T he genera of Sap indales in the southeastern United States. J. Arnold Arboretum , 44 :462-501. Brizicky, G . K., 1964. T h e genera o f Rhamnaceae in t he southeastern United States. J. Arnold Arboretum, 45 :439-463. Brown, C . A., 1938. The fl ora o f Pleistocene deposits in t he western F lorida p arishes, West Feliciana Parish , a nd East Baton Rouge Parish, Louisiana. La. Dept. Con.1·erv., Ceo/. Bull,. 12:59-96. D avis, J . H., 1946. The peat deposits of F lorida. Their occurrence, development, and uses. Fla. Dept. Couse,..., Fla. Geo/. Surv. Bull., 30: 1-247. Deevey, E. S., 1949. Biogeography of the Pleistocene. Bull. Ceo/. Soc. Am., 60:13 15- 1416. D ilcher, D. L., 1963. Cuticular analysis o f Eocene leaves of Ocotea obtusifolia. Am. J. Bot., 50: 1-8. D ressler, R. L , 1954. Some floristic relationshiQS between Mexico and the United States. R!todora, 56: 8 1-96. E lias, T ., 1972. T he genera of Juglandaceae in the southeastern United States. J. Amo/d Arboretum, 53:26-5 1. E lsik, W. C., 1968. Pa lynology of a Paleocene Rockdale lignite, Milam Coun ty, Texas, t. Morpho logy and taxonomy; 2. Morphology and taxon omy (end). Pollen Spores, I0:263- 3 14; 599-664. Fernald , M. L., 1931. Specific segregations and identities in some fl oras of eastern North A merica and the Old Wo rld. R!todora, 33:25- 63. Garcia, E., 1970. Los climas del estado de Veracruz. Anales lnst . Bioi. Un iv. Nat. Auton. Mex., 41: 3-42. Gomez Pompa, A., 1966. Estudios Botanicosen Ia Region de Misantla , Veracruz. lnst. Mex. Resursos Naturales Renovables, M exico, D.F .,I 73 pp. Gomez Pompa, A., H ernan dez Pallares, L. and Sousa Sanchez, M ., 1964. Estudio fitoeeologico de Ia cuenca in termedia del R io Papaloapan. Pub /. Esp. lust. Nat. " "'· For . Mex., 3 : pp.37- 90. Gomez Pompa, A. and Nevlin g, L . I., 1970. La fl ora de Veracruz. A nates lnst. Bioi. Univ. Nat. Auton. M ex.,41:1-2. Gomez Pom pa, A. and Leon Cazares, J. M ., 1970. Mapas de vegetacion en zonas calidas y su importancia. Bot. Esp. lnst. Nal. lnv. For. Mex., 5:1- 11. Gonzalez Guzman , A. E., 1967. A Palynological S tudy on the Upper Los Cuervos and Mirador Formations. (Lower and Middle Eocene; Tibu Area, Colombia). Brill, Leiden, 68 p p. Gordon, A. G., 1968. Ecology o f Picea chihuahua/Ill Marti nez. Ecology, 49:880-S96. G raham, A. and H eimsch, Ch., 1960. Pollen a nalysis of some Texas peat deposits. Ecology, 4 1 :751763. . G ray, J ., 1960. T emperate po llen genera in the Eocene (Claiborne) flo ra, A labama. Science, 132:80 8810.

313

3 14

A. GRAHAM

Watts, W. A ., 197 1. Postglacia l <~n cLi.n t.câ&#x20AC;˘:glaciaJ vegetat ion history of southern Georgia and cen tral _ Florida. Ecolog)', 52:676- 690. W hitehead, D. R., 1965. J>aiynology and Pleistocene phytogeogniJ>hy of unglaciated eastern North America. In: H. E. W right and D. G. Frey (Editors), The Quatcmary of tile United States. Princeton Univ. Press, Princeton, N. J ., pp.417- 432. Whitehead, D. R., 1967. Studies of fu ll-g lacial vegetation and climate in southeastern United States. In: E. J. Cushing and H . E. Wright (Editors), Quatemary Paleoecology. Y ale Univ. Press, New Haven, pp.237- 248. Whitehead, D. R. and Barghoorn, E. S., 1962 . Pollen-analytical in vestigations o f Pleistocene deposits from western North CMolina and Sout h Carolina. Ecol. Monogr., 32:347-369. W illiams, L. 0. and Molina, R. A., 1970. The J ugla ndaceae of Guatemala. Fieldiaua (Bot.}, 32:207209. Wilson, K. A. and Wood, C. E., 1959. The genera of Oleaccae in the southeastern Un ited States. J. A mold Arboretum, 40:369-384 . Wymstra, T . A., 197 1. The Palynology of tile Guiaua Coastal Basiu. De Kcmpenaer, Oegstgccst, 62 p p. Wright, H. E., 197 1. Late Quaternary vegetational history of North America. In : K. K. Turekian (Editor), The Late Ceuozoic Glacial Ages. Yale Univ. Press, New Ha ven, pp.425-464.

Clrapter 9

Literature on Vegetational History in Latin America 1 A LAN GRAHAM Department of Biological Sciences, Kent State Unil'ersity, Keul, Ohio, U.S.A .

Summary A bibli ography of approximately I ,000 papers is presented, d ealing with publ ications on the paleobotany and paleopalynolo gy o f Latin America. The geographic regions incl ude Mexico, Central America, The Antill~s, and South A merica. A selected group of more recent review or synt hesis papers on related subjects such as biogeography, historical geology, and po llen morphology of modern forms from the neotropics is also included. I

Introduction

I i'

Preh mmary lo a st udy of Cenozoic plan t communities about the Caribbean Basi n a bibliography was assembled of papers relating to the paleobotany, paleopalynology, pollen morphology of modern predo minantly neotropical taxa, and the ancillary subjects of historical geology (especially land-sea relatio nships), systematics, and biogeography of Latin American biotas. An eO"ort was made to acq uire a relatively complete listing of paleobotanical and paleopalynological papers, while the ancill ary subjects are represented b y a selection of more recent papers, particularly of a review or s ummary nature. The compilation of t hese papers was initially undertaken preliminary to a Catalogue of Cenozoic Plants of Latin America, comparable to LaMotte's (1952) catalogue for North America. Whether this will ultimately p rove worthwhile is open to q uestion since at present many identifications, particularly in the older literature are erroneous and are being revised in current stud ies, age assig nments are in need of revision, and in a number o f cases the original specimens are lost or have been destroyed. Nonetheles~ the .literature itself is important regardless of whether it is to be compiled into a catalogue or incorporated into individual papers dealing with more - specific facets of Latin American vegetational history. The total number of paleobotanical and paleopalynolog ical papers listed is 960. Of this number 87 deal with fossil plants fro m Mexico, the earliest being those o f Ehrenberg (1 839, 1844, et seq.) cited in Maldonado-Ko erdell's (1950) catalogue. ln Central America 22 published studies have been made, the earliest li~ted being 1

Research fo r this study was supported by NSF grants GB-5671

and GB-11 862.

A. GRAHAM

LITERATURE ON VEGETATIONAL H ISTORY IN LATIN AMERICA

Newberry's in 1888 on fossi l pla nts f1 om Honduras. From the An tilles 31 known studies arc included. The oldest reference is by an anonymous a uthor concerning petrilied wood from Antigua (1818) as cited in La Molle's (1952) catalqgue. The largest group of papers deals wi th South America (including Trinid ad; papers on Antarctica are not included), numbering 820. The oldest included is that of Karsten (1850) mentioning some leaves associated with coal near Santa Maria and Nariqual, Venezuela (see reference to Schlagintweit, 19 19). . Undoubtedly a number of papers have been missed in this survey, and hopefully supplements can be provided periodically to bring the bibliography up to date. Approximately one-half of the citations have been checked against the original publication. T he remainder were taken fr om references cited in various publications and may include inadvertent errors to be corrected in future 1evisions. In the meantime it is offered as a literatu re guide to those interested in the origin and qvolution of Latin American plant communities. In the bibliography age of the sedi ments follows th at given in the original publication. Species lists are provided for papers deali ng with fossi l flo ras in northern Latin America (Mexico, Central America, and the Antilles).

Childs, 0. E. and 13ccbc, B. W. (Edito rs), 1963. Symposium, Backbone of the Americas. Mem. Am. Assoc. Pet. Gcol. (Tulsa), 2: 320pp. Constance, L., t963. 1ntroduction and historical review. In : SJ•mposinm, Amphilropirallklationships in the Herbaceous Flom a/the Pacific Coast of North and South America. Q. Rev. Bioi., 38 : 10911 6. . Corral, J. 1. , 1939. La union de Cuba con el continente Americana. Re••. Soc. Cuban lng., 33: 581681. Darlington, P. J., 1938. The origin of the fauna of the Greater Antilles, with discussion of dispersal of animals o ver water and through the air. Q. Re••. Bioi., I J: 274-300. Da rlington, P. J., 1957. Zoogeography: The Geographical Distribution of Animals. Wiley, New York, N.Y., 675 pp. Darlington, P. J ., 1965. Biogeography of the Sou them Endoftlte World. Barv. Univ. Press, Cambridge, 236 pp. Durham, J . W. and Al lison, E. C., l960. The geologic history of 13aja California and its marine faunas. In: Symposium, The Biogeography of Baja Califomia and Adjacent Seas. Syst . Zoo/., 9:47-91. Fittkau, E. J., lilies, J., K linge, H., Schwabe, G. H. and Sioli, H. (Edit ors), 1968-1969. Biogeogmphy and Ecology in So111/r America. 2 Vols., Junk, The Hague, 946 pp. G6mez-Pompa, A., Hernandez Pa llares, L. and Souza Sanchez, M., 1964. Estudio fitoecologico de Ia <;ucnca intcrmedia del Rio Papaloapan. Contrib. Estud. Era/. Zonas C{J/ido-Hwncdas de Mexico, 3: 37-90. Griscom, L., 1942. Origin and relationships of the faunal areas of Central America. Proc. Am. Sci. Congr., 8th, 3: 425-430. · HalTer, J., 1970. Geologic-climatic history and zoogeographic significance of the Uraba region in northwestern Colombia. Caldasia, 10:603-636. Harrington, H. J., 1962. Paleogeographic development of South America. Bull. Am. Assoc. Pet. Geologists, 46: 1773-18 14. Hellmich, W., 1940. Die Bedeutung des ~Andcnraumes im biogeographischcn Bilde Siidamerikas (Ergebnisse und Probleme zweier Reisen in Siidamerika). In: Tier und Umwe/1 in Siidamerika. lbero-Amerika Studien, 13:63-91. Hershkovitz, P. , 1966. Mice, landbridges and Latin American faunal interchange. In: R. L. Wenzel and V. J. Tiplon(Editors), Ectoparasites of Panama. Field Mus. Nat. Hist. (Chicago), pp. 725-75 I. Hess, H. H. (Editor), 1966. Caribbean geological inves tigations. Ceo/. Soc. Am., Mem., 98:3 10 pp. Hoffstetter, R., 1954. Les mammiferes fossiles de !'Amerique du Sud et Ia biogeographie. Rev. Gen Sci., 61: 348-377. Jenks, W. F. (Editor), 1956. Handbook of South American geology. Geol. Soc. Am., Mem ., 65: 378 pp. Khudoley, K . and Meyerhofl', A. A., 1971. Paleogeography and geological history of the Greater Antilles. Geol. Soc. Am., Mem., 129: 199 pp. Koopman, K., 1958. Land bridges and ecology in bat distribution on islands o ff t he northern coast of Sou th America. Evolution, 12: 4 29-439. Lahey, J. F., 1958. On the origin of the dry climate in northern South America and the southern Caribbean. Dept. Meteorol., Univ. Wise. Sci. Rep., 10: 290 pp. Lent, H. (Editor), 1967. Alas do Simposio sabre a Biota Amazonica. 7 Vols. Publ. Conselho Nacl. _ Pesquisas, Rio de Janeiro. (especially Vol. I, Geociencias; Vol. 4, Botanica.) Lowe-McConnell, R. H. (Editor), 1969. Speciation in Tropical Environments. Acad. Press, London, 246 pp. Maldonado-Koerdell, M., 1964. Geohistory and paleogeography of Middle America. In: R. Wauchope and R. C. West (Editors), Handbook of Middle Ameriam Indians. Univ. Texas Press, Austin, pp. 3-32. Mayr, E. (Editor), 1952. The problem of land connections across the South Atlantic with special reference to the Mesozoic. Am. Mus. Nat. His/. Bull., 99: 79-258. James, N. P. and Mountjoy, E. W., 1971. A 60,000 year old terrace on northern Barbados and its importance to Late Pleistocene climatic changes. Geol. Soc. Am., Abstr., Northeast. Sect., p.39. Mitchell, R. C., 1955. Le Tertiaire de Porto-Rico et le developpement Tertiaire des Grandes Antilles. Bull. Geol. Soc. Fr., 4: 213-224. · Moore, R., 1945. The transverse volcanic biotic province of central Mexico and its relationships to adjacent provinces. Trans. San Diego Soc. Nat. Hist., 10:219- 235.

316

General bibliographic references Andrews, H . N ., 1970. Index of generic names of foss il plants, 1820-1965. U.S. Geol. Sun•. Bull., I 300: 354 pp. LaMotte, R . S., 1952. Catalogue of the Cenozoic plants of North America through 1950. Geo/. Soc. Am.,Mem.,5 l :38l pp. . Maldonado-Koerdell, M., 1950. Los estudios paleobotanicos en Mexico, con un catalogo sistematico de sus plantas fosiles. Bol. fnst. Geol. , Univ. Nac. Autonoma Mex., (Mexico, D.F.), 55:72 pp. Manten, A. A., 1969. Bibliography of Palaeopalynology, 1836-1966. Rev. Palaeobot. Palynol., Spec. Vol.,8: 1-572. Menendez, C. A., 1958. Bibliografia paleobotan ica Argentina, I. Lilloana, 2: 29 1-332. Menendez, C. A., 1967. Bibliografia paleobotanica Argentina, II. Lilloana, 9: 239- 261. Menendez, C. A ., 1968. Bibliografia paleobotanica de America del Sur. Rev. Mus. Argent. Cienc. Nat. Bemardino Rivadavia, I : 13 1-229.

Biogeography and historical geology

(with emphasis on pathways of migration and land-sea relationships) Alain, H ., 1958. La flora de Cuba, sus principales caracteristicas, su o rigen probable. Rev. Soc. Cuban Bot., 15: 36-59; 84-96. (Similarities in vegetation between Central America and Mexico and the Greater Antilles suggest a land bridge between Cuba and the Yucatan- Honduras region.) Anonymous, 1971. How the Isthmus of Panama got there. Sci. News, 99:279- 280. Belding, H. F., 1955. Geological development of the Colombian Andes. Proc. Conf Latin-American Geol., Univ. Texas, Austin, pp.43- 63. Bond, J., 1948. Origin of the bird fauna of the West Indies. Wilson Bull., 60: 207-229. Bucher, W. H., 1952. Geologic structure and orogenic h istory of Venezuela. Geo/. Soc. Am., Mem., 49: 11 3pp. Sutterlin, J., 1956. La Constitution Geologique et Ia Structure des Atrtilles. Centre Nat/. Rech. Sci., Paris, 453 pp.

317

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318

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LIT ERATURE ON VEGETATfONAL HISTORY IN LATIN AMERfCA

Odum, H. T. (Editor), 1970. A tropicall?aill Forest: A .rll/dy of l rmdiation and Ecology at El Verde, Puerto Rico. Div. Tech. Inform., U.S. A.E.C., Oak R idge, Tenn., 1066 pp. O lson, E. C., and McGrew, P. 0., 194 1. Mammalian fauna from the Pliocene of Honduras. Ceo/. Soc. Am. Bull., 52: 1219- 1244. [Absence of mammals o f South American· origin suggests no land connect ion existed between the two Americas during the Lower Pliocene, and the presence o f a northern type fauna ind icates there was no marine porral a1 the Isthmus of Tehuantepcc. The authors contend that the route from the north across Tehuantcpec was open during the Lower Pliocene to t he Isth mus of Panama, a nd agree with Woodring and o thers that no land connection was available between North and South America until La te Pliocene time.] Pa gney, P., 1966. Le clima t des Antilles. Trav. Mh11. lnst. Hant es £111d. Am. Latine, 15:2 Vols. Raven, P., 1963. Amphitropical rela tionships in the floras of North and South A merica. In: Symposium, Amphitropical Relationships in the Herbaceous Flora of the Pacific Coa~t of North and Somh America. Q. Nev. Bioi., 38 : 151- 177. Rzcdowski, J., 1962. Contribuciones a Ia fitogcografia floristica y historia de Mexico. 1. Algunas cons ideracion~s acerca del clemento endemico en Ia nora Mexicana. Bol. S oc. Bol. Mex., 27: 52-65. Savage, J. M., 1966. The origins and history of the Central American herpetofauna. Copeia, 1966: 719-766. Schnell, R., 1967. Problc mes biogcographiques compares de J'Hy laca Amazonienne et de Ia fo rct dense tropicale d 'Afrique. In : H. Lent, (Editor), Atlas do Simpo~"io sabre a Biota Amazonica, Vol. 4 ( Botanica) . Publ. Consclho Nac l. Pcsquisas. Rio de Ja neiro, pp. 229-239. Sch uchert, C., 1935. Historical Geology of the Ami/lean-Caribbean Region. Wiley, New York, 811 pp. Senn, A., 1940. Paleogene of Barbados and its bearing on history and structure of Antillean-Caribbean region. Bull. Am. Assoc. Pet. Geo/ogist.r, 24 : 1548- 1610. Simpson, G. G., 1950. History of the fauna of Latin America. Am. S ci ., 38: 361- 389. Simpson, G. G., 1956. Zoography of West Indian land mammals. Am. Mus. No o•il., 1759. Smith, A. C., 1967. T he presence of primitive angiosperms in the Amazon Basin and its significance in indicating migrational routes. In: H . Lent. (Editor), Alas do Simposio sobre a Biola Amazonica, Vo l. 4 ( Botanica) . Publ. Conselho Nacl. Pcsquisas, Rio de Janeiro, pp. 37- 59. Smith, L. B., 1962. Origins of the flora of southern Brazil. Contrib. U.S. Nat/. Herb., 35 : 21 5-249. Stirton, R . A., 1950. Late Cenozoic avenues of d ispersal for terrestrial animals between North America and South America. Abstr. Ceo/. Soc. Am. Bull., 61: 1541- 1542. · [Th roughou t most of the Cenozoic the dispersal of terres trial vertebra tes between North and South America was blocked by water barriers. In Late Pliocene a land route was established, and mammals spread both ways across the Isthmus. This pat hway is blocked again today by a formi dable barrier in a dense rai n-forest that stretches across pa rt of Panama an-d northwestern Colombia. T wo o rogenies were involved, the first eliminating the earlier water barriers and the second resulting in warm moist-laden air to be drawn towa rd low-pressure areas to the east of the Andes, c ondensing over coastal areas and western mountain fron ts. T his has given part of Pan ama a nd northwest Colombia a perpetual rainy season and a rain-forest barrier th at blocked the passageway of the later Pleistocene a nd recen t mammals.] Stuart, L. C., 1954. A description of a subhumid corrido r across northern Central America with comment o n its hcrpetofa unal indicators. Con/rib. Lab. Vertebr. Bioi., Univ. Mich. ( Ann A;·bor) , 65: 1-26. [Discontinuites in the distribution of certa in amphibians and reptiles th ro ugh the dry-lands of southern Mexico and central and eastern G uatemala s uggested a subhum id corridor between the Isthmus of Tehuantepec a nd the deserts of eastern Guatema la and northern Honduras. Such a corridor was found through the valley of the Rio Grijalva of Chiapas a nd those of the Negro and Motagua of Guatema la. This corridor is comprised of valleys lying for the most part below an elevation of 1000 m but broken by divides that may attain a height of 2000 m. It is indicated tha t the corridor had its origin during the Pliocene when the major topographic features o f the valleys were outlined and their s ubhumid climatic conditions were initiated.] Sympos ium, 1960. The biogeography of Baja California and adjacent seas. Syst. Zoo/., 9:47- 232. S;mposium, 1963. Amphitropical relationships in the herbaceo us flora of the Pacific coast of North and South America. Q. Rev. Bioi., 38 : 109- 177. T obisch, 0. T., 1968. G neissic amphibolite at Las Palmas, Puerto Rico, and its significance in the

31 9

eacl¥_hlstory of the G reater Antilles island arc. Ceo/. Soc. Am. Bull., 79: 557-574. Trelcasc, W., 1918. llearing o f the distri bution of the existing nora of Cent rai_America and the Ant illes on fo rmer land connections. Ceo/. Soc. Am. Bull., 29 : 649- 656. Van Steen is, C.{). G . J., 1962a. The land-b ridge theory in bo ta ny. Blumea, I I : 235- 372. Van Steen is, C. G. G. J., 1962b. The distri bution of the mangrove genera and thei r palaeogeographical implication. K. Ned. Akad. Wei. Pmc., Ser. C, 65: 164- 169. Weber, H., 1958. Die Paramos von Costa Rica und ihre pnanzcngcographischc Verkettung mit den l:lochlandern Slidamerikas. Ablt. Akacl. Wiss. Lit .. Mainz , Math. Nalurwiss. Kl., 3 : 1-78. Weyl, R., I 965. Die palaeogeographische Entwicklung des mittelamerika nisch-wcstindischcn Riiumcs. Ceo/. l?undsc/wu, 54: 1213-1240. (Sec also English trans lation, Bol. l uj: Asoc. Veuez. Ceo/., Min. Pet., 9:99- 120, 1966). Whitmore, F. C. and Stewart, R. H., 1965. Miocene mammals and Central American seaways. Science, 148: 180-185. [The fossil mammal fau nas of North and Sout h America indicate the t wo continents were separated from Paleocene or earlier time until La te Pliocene. Folding and faulting was nearly continuous for a long time, making it difficult to postula te the stability requi red for a land bridge. Ra ther, the area was probably characterized by shifting patterns of isla nd g roups a nd peninsulas attached to one co ntinent o r the other. D arlington ( 1957) believes that Central America was an island during most of t he Tertiary, cut off from b oth North and Sollth A merica; Simpson (1950) believes it was connected to North A merica during the Tertiary. Tertia ry mammal remains fro m the Cucaracha deposits support the concept that No rth and Central America were continuously connected during the Tertiary as does the presence of a Pliocene mammal fauna of a N orth American type in Honduras, described by Olson and McGrew (194 1).] Wiggins, I. L., 1960. The origin and relationsh ips of the land flo ra. In: Symposium, The Biogeography of Baja California and Adjacenl Seas. S ysl. Zoo/., 9: 148-165. Wilhelmy, H., 1954. Die klimamorphologische und pflanzcngeographischc Entwicklung des Trockengebietes am N ordrand Siidamerikas seit dem Pleistoziin. Die Erde, 6: 244-273. Willis, B., 1932. Isthmian Links. Bull. Geo/. Soc . Am.,43 : 917-952. Woodring, W. P., 1949. The Pa nama land bridge. Science, 109: 4 37. Wood ring, W. P., 1954. Caribbean land and sea through the ages. Bull. Ceo/. Soc. Am., 65: 719-732. Woodring, W. P., 1966. T he Panama land bridge as a sea barrier. Trans. Am. Phil. Soc., 110:425-433.

Paleobotany of Mexico

AgUilera, J. G., 1907. Aper~u sur Ia geologie du Mexique pour servir d'explication Ia carte geologique de !'Amerique du Nord. Congr. Ceo/. Int., Compt. Reud., JOe, M exico, 1906, 1: 227-248. [Triassic of Sonora, Mexico : Abietiles atf. A. carolinensis Fonta ine, Aslerocarpus f alcarus (Emmons) F ontaine, A." virginiensis Fonta ine, A. whitneyi Newberry, Baiera mw1steriana (Presl.) Heer, B. radiata Newberry, Cladophlebis ( Andriania) atf. A. barulhina Druguiere, Cte11ophyllum robustum Emmon~. Diooniles atf. D. rigidus Andrae, Equiselites aff. E. 11111/IS/eri (Sternberg) Bro ngniart, Macrotaeniopteris e/ega11s Newberry, M. magnifolia Rogers, Merle!lsidts bullatus Bunbury, M. mexicanus Newberry, Nilsonia polymorpha Schenck, Otozamiles macombii Newberry, Podozamites? crassifolia Newberry, Pterophyllumfragi/e Newberry, P . robustum Newberry, Raphae/ia ? americana Newberry, R .? remondi Newberry, Sphenozamiles rogersianus Fontaine, Taeniopteris glossopleroides Newberry, Zamites occidenta/is Newberry.] Aguilera, J. G . and Ordo nez, E., 1893. Datos para Ia Geologia de M exico. Tae ubaya, D.F., 88 pp. [Triassic of Sonora, Mexico : Abielites aff. A. caroliuensis Fontaine, Asterocarpus fa/cat us (Emmons) Fo ntaine, A. virginiensis Fontaine, A. whitneyi Newberry, Baiera radiata Newberry, Cladophlebis? ( Andriania) aff. A. baruthina Bruguiere, C/enophyllum robustum Emmons, Cycudiles? sp., Diooniles aff. D. rigidus Andrae, Equiseliles aff. £. munsteri .(Sternberg) Brongniart, Ginkgo? sp., Macrotaeniopteris elegans Newberry, M. magnifolia Rogers, M er/ensides bullatus Bunbury, M. mexicanus Newberry, Otozamites macombii Newberry, Pecopteris aff. P. pinnali/ida Gutbier, Podozamites? crassifo/ia Newberry, Plerophy llum fragile Newberry, P. robustum Newberry, Raphaelia? remondi Newberry, Taeniopteris g/ossopteroides Newberry.]

·I

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LITERATURE ON VEGETATIONAL H ISTORY IN LATIN AMERICA

Aguilera, J. G. et al., 1896. Bosqucjo geologico de Mexico. Bal. Ins/. Ceo/. Mex., 4/6: 267 pp. [Triassic of Sonora, Mexico: Ab7t!fites aiL A. caro/inensis Fonta ine, Asterocarpus jitlcatu., (Emmons) Fontaine, A. vitxiniemis Fontaine, A. whillteya Newberry, Baiem 1/JJ/11.\'leritma (Prcsl.) Hcer, JJ. mdiata Newberry, Clrulopjllebis? ( Antlriania) bamthina Bruguicre, Ctenophyllum robaslttm Emmons, Dioonites afT. D. rigidus Andme, Equisetiles ali. £. numsteri (Sternberg) Brongniart, Macrotaeuiopteris e/egmrs Newberry, M. magnifo/ia Rogers, Mertensitle.1· bttllaltts Sunbury, M. mexicanus Newberry, Ni/sonia polymorplw Schenck, Otozamires nwcombii Newberry, Podozamites?crassifolia Newberry, Pleroplry/Jumfragile Newberry, Rap/welia? americana Ncwbcrry, R.? remondi Newberry; Spltenozamites rogersianus Fontaine, Zamiles otcidelllalis Newberry.] Alvarez, T. and Gonzalez Quintero, L., 1969. Analisis polinico del contenido gastrico de murciclagos Glossophaginae de Mexico. Anales Escue/a Cienr. Bioi., Ins!. Politec. Nac. (Mexico, D.F.), 18: 137-165. Arsene, H. G. and Marty, P., 1923. Stlf quelquesemprcintcsdc fcuillcs fossiles deJa Lama del Zapotc a Morelia, Michoacan, Mexique. Mimcogr., Covington, Louisiana (U.S.A.), 16 pp. [Pleistocene of Michoacan, Mexico : Quercus acutifo/ia Noe, Q. fulva Liebmann, Q. /(IJrceolata H.B.K.] Darghoorn, E. S., Wolfe, M. K . and Clisby, K. H., 1954. Fossil maize from the Valley of Mexico. Bot. Mus. Leaflets, Harvard Univ., 16: 229- 240. Berry, E. W., 1918. Paleogr.aphic significance of the Cenozoic floras of equatorial America and adjacent regions. Bull. Geol. Soc. Am., 29:631- 636. Derry, E. W., 1923. Miocene plants from southern Mexico. Proc. U.S. Nat/. Mus., 62: 1-27. [Miocene of Oaxaca, Mexico: Acroslic/rummexicamtm Berry, Cymnogramne wadii Berry, Auacardites lmrceolatus Be rry, Anona saraviana Berry, Bignouoides orbicularis. Berry, Counams C(trl/lenensis Berry, Crescentia cuwrbirinoides Berry, Dioclea? mexicana Berry, Drypetes elliptica Berry, Fagara wadii Berry, Ficus? ra/amancana Berry, Coeppertia cf. G. tertiaria Berry, Couania miocenica Berry, Cuettarda cookei? Berry, Cynmoca/dus wadii Berry,Lecytlti«ophyllum couratarioides Berry,Leguminosites oaxacensis Berry, Melasromites angus/us Berry, M. obovatus Berry, Moquillea mexicatra Berry, 111yrcia saraviana Berry, Nectandra areola/a Engelha rdt, N. te/mantepecensis Berry, Rondelelia? sp. Miocene of Veracruz, Mexico: Cymnogramme wadii Berry, Allamanda camrenensis Berry, Apocynophyllum mexicanum Berry, Cedrela miocenica Berry, Comrams t·armenensis Berry, Coussapoa 1•eracruziana Berry, lnga miocenica Berry, Leguminosites mexicamrs Berry, Liquidambar incerta Berry, Me/asromites obovarus Berry, Mespilodaplme pa/omarensis Berry, Simaruba veracruziana Berry.] Berry, E. W., 1942. Mesozoic and Cenozoic plants of South America, Central America and the Antilles. Proc. 8th Am. Sci. Congr., Ceo/. Sci., 4:365- 373. Bopp-Oeste, M.G., 1958. La paleobotanica, sus methodes y aplicaciones. Publ.lnsr.Naci.Antropo/. His!. Dir. Pre!tist. (Mexico, D.F.), 5:5-44. Bopp-Oeste, M. G., 196 1a. Sinopsis de los estudios sabre Ia paleobotanica en Ja Republica Mexicana. 5th Int. Kongr. Vor- und Friihgescltichre (Hamburg, /958). G. Mann, Berlin, pp. I 12- 119. Bopp-Oeste, M. G., 1961 b. El analisis de polen con·.referencia especial ados perfiles polinicos de Ia Cuenca de Mexico. Homenaje a Pablo Martinez del Rio, Ins/. Nacl. Antropol. Hist. (Mexico, D.F.) , pp. 49- 56. Bo pp- Oeste, M.G., 1961c. La investigacion palinologica en Mexico. Tlatoani, 14-15: 15- 25. Bryan, K., 1948. Los suelos complejos y fosiles de Ia altiplanicie de Mexico en relacion a los cambios. Bol. Soc. Ceo/. Mex., J3: 1- 20. Burckhardt, C., 1930. Etude synthetique s ur le Mesozoique Mexicain. Mem. Soc. Paltiontol. Suisse, 49- 50: 280 pp. [Cretaceous from region de Piedras Negras, Mexico: Ceonomiles tenuiracltis Lcsquereux (White, in Burckhardt)] Clisby, K. H . and Sears, P. B., 1955. Palynology in southern North America. 3. Microfossil profiles under Mexico City correlated with the sedimentary profiles. Bull. Geol. Soc. Am., 66: 511- 520. Cross, A. T ., Thompson, G. G. and Zaifzeff, J. B., 1966. Source and distribution of palynomorphs in bottom sediments, southern part of Gulf of California. Mar. Geol., 4 : 467-524. Deevey, E. S., 1943. Inte nto para las culturas medias del Valle de Mexico mediante a nalisis de polen. Ciencia (Mexico, D.F.) , 4 :92-105. Deevey, E. S ., 1944. Pollen analysis and Mexican archeology: An attempt to apply the method. Am. Antiq., 10: 135- 149.

an·.

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(" ... the first report of pollen spectra in Mexico was by Deevey (1944)" (Scars, 195 1).] Deevey, E. S., 1956,-bimnology studies in Middle America, with a chapter on Aztec limnology. Tmns. Conn. Acad. AI'IS Sci., 39: 213-328. Delcvoryas, T., 1966. Hunting fossil plants in Mexico. Disco1•ery, 2:7- 13. Delevoryas, T., J969. Glossopterid leaves from the middle Jurassic of Oaxaca, Mexico. Science 165: 895-896. ' Delcvoryas, T. and Gould, R. E., 197 1. An unusual fossil fructification from the J urassic of Oaxaca, Mex1co. Am. J .Bor., 58:616- 620. [DescribcdPerezlariooaxacensisgen et sp. nov. from the middle Jurassic Zorrillo Formation of Oaxaca, Mexico.] Diaz Lozano, E., J916. Dcscripcion de algunas plantas Liasicas de Huayacocotla, Veracruz; Algunas plantas de Ia Hora Liasica de Huauchinango, Pucbla. Boi.Iust. Ceo/. Mex., 34: 1-18. [Jurassic of l'uebla: Clteirolepis? sp., Cyc(lt/eo.lpermus? sp., Otozamires cf. 0. hewroquei Saporta 0. afT. 0 . obtustts Lindley a nd Hutton, 0. sp. 3, Spltenozamites?sp. 2. ' Jurassic of Veracruz: Aletltopteris? sp., Cycado/epis sp., Otozamites hespera Wieland, 0. hespera var. latifolia Wieland, 0 . molinirmus Zigno, 0. oblttstts var. liassicus Wiela nd, 0. reg/ei (Brong.) Saporta, 0. cf. 0. pteropltylloides Brong., 0. sp. I , 0. sp. 2, Podozamites sp., Pltrophyl/um propiucum Goeppert, P. sp. I, 2, 3, Ptilopltyllum actttifo/irun var. maximum Feist mantel, P. sp., P. sp. nov. ?, Splteuozamiles?sp. 1.] Diaz Lozano, E. , 1917. Diatomcas fosilcs Mexicanas. An. lust. Geol. Mex., 1:27 pp. Diaz Lozano, E., 1920. Depositos diatomifcros en cl Valle de Taxi, Ixlahuaca, Estado de Mexico. An. Ins/. Geo/. Mex., I: 19 pp. Diaz Lozano, E., 1928. Los microorganismos fosile s y Ia geologia del petroleo. JJoi.Petro/. (Mexico, D.F.), 26:397- 400. Diaz Lozano, E., 1942. Sedimentos diatomifcros Mcxicanos. An. lsi Congr. Panamericano lng. Minas Ceo/. (Samiago, C!tile), Geo/., I: 633- 640. Dorf, E., 1945. Observations on the preservation of plants in the Paricutin area. Trans. Am. Geopilys. Union, 26: 257- 260. · Dorf, E., 195 1. Lithologic and Ooml facies in the Paricutin ash deposits, Mexico. Trans. N. Y. Ac(ld. Sci., 13: 317-320. Ehrenberg, C. G., 1839a. Mikroskopische Analyse des im Jahr 1686 in Curland von Himmel gefallen Meteors- Papier. Abh. Preuss. Akad. Wiss., Berlin, 14 pp. (see also Neues Jarltb. Mineral., Geol., Palaeonr., 1840: 249- 250). Ehrenberg, C. G., J839b. Zwei neue Lagerstiitten fossiler Infusorien in Frankreich und New York. Abit. Preuss. Akat/. Wiss., Berlin, 3 p. (sec a lso Neues Jal'lrb. Mineral. , Ceo!., Palaeonl., 1841: 733-735). Ehren berg, C. G., 1844. Ober eincn deutlichen Einfluss des unsichtbar kleinen organischen Lebens als vulkanisch gefrittete Kiesei- Masse auf die M assen- Bildung vom Bimstein, Tuff, Trass, vulkanischen Konglomcrat und aueh auf das Mutter-gestein des Nordasiatischen Marekanits. Abh. Preuss. Akad. Wiss., Berlin, pp. 324-344. Ehrenberg, C. G., 1854. Mikrogeologie des Erden tmd Felsen Scilaffende Wirken des Unsicltlbar Kleinen Selbsrandigen Lebens auf der Erde. L eipzig, 88 pp. Ehrenberg, C. G., 1866. Phytolitharien-Tuff a ls Gebirgsart im Toluca-Tale von Mexiko. Ablt. Preuss. Akad. Wiss., Berlin, pp. 158-168. (Translation into Spanish, La Natttraleza, Jst Ser., 3: 118- 132, in 1874). Ehrenberg, C. G., 1869. Ober miichtige Gebirgs-Schichten vorherrschend .aus mikroskopischen Bacillarien unter und bei der Stadt Mexiko. Abil. Preuss. Akad. Wiss., Berlin, 66 pp. Enciso de Castro, M. T., J958. Notas sabre Ia separacion y estudio de polen y esporas fosiles en materiales arcillosos. Bol. Asoc. Mex. Ceo/. Pet., 10: 633-641. Espinosa de G . Rul, J. and Rzedowski, J., 1966. Florula del Pleistoccno Su perior del Cerro de La Estrella proximo a Ixtapalapa, D.F. (Mexico). An. Escue/a Nacl. Ciettc. Bioi., Inst. Noel. Politec., 16:9- 39. [Arbutus sp., Buddleia cordata H.B.K., Quercus ila/miiTrel. , Q. ilartwegiBenth., Q. /oeta Liebm., Q. Iaurino H um b. and Bonpl., Q. repanda Hum b. and Bonpl., Q. rugosa Nee, Q. rugu/qsa Mart. and Gal., Ribes sp., Salvia polystachya Ort., Senecio sp., Symp!toricarpos microphyl/us H.B.K.] Felix, J. and Nathorst, A. G., 1893. Versteinerungen aus dem mexicanischen Staat Oaxaca. In:

322

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J. Felix und H. Lcnk, Beitriige Gcalogie wul Paleontologie der Republik Mt!xico, Teil 2. f elix, l eipzig, pp. 39- 54. [Tertiary of O:~xaca, Mexico: Pa/moxylon cellu/osum Knowhon, P. cf. stellatum Unger, AcacioxylvnteJwx nov. sp. Lower Cretaceous of Oaxaca: Sequoia cf. ambigua Hcer, S. cf. reiclrenbachi Geinilz, Pseudofrene/opsisfeli xi gen. et sp. nov.] Hanna, G. D. and Grant, W . M., 1926. Miocene mari ne diatoms from Maria Madre Island, Mexico. Calif. Acad. Sci. Prac., 15: 115-1 92. Humphreys, E. W., 1916. Triassic pla nts from Sonora, Mexico, including a Neocalamites no! previously reported from North America . Mem . N.Y. Bot. Gard., 6:75-78. [Triassic of Sonora, Mexico: Asterocarpus fa/emus (Emmons) f ontaine, A. virginiensis Fontaine, Cycadeomye/on? sp., Macmtaeniopteris sp., Merteusides bullatus Bunburry, Neocalamites can·erei (Zeitler) Halle, Otozamites macombii Newberry, Palissya? sp., Zamites powe/li Fontaine, Z. sp. I, Z. sp.2.] Hurd, P. D., Smith, R. F. and Durham, J. W., 1962. The fossi liferous amber o f Chiapas, Mexico. Ciencia, 21: 107- 118. Hutchinson, G. E., Patrick, R. M. and Deevey, E. S., 1956. Sediments of Lake Patzcuaro, Michoacan, Mexico. Geo l. Soc. Am. Bull., 67: 1491- 1504. Knowlton, F. H ., 1918. Relations between the Mesozoic floras of North and South America. Bull. Geol. Soc. Am., 29 : 607-614. Langcnheim, J . H., Hackner, B. L. and Darlic u, A., 1967. Mangrove pollen at the depositional site of Oli~;o-M i ocene amber from Chiapas, Mexico. Bot. Mus. Leaf/., Harv . Univ. , 21: 289- 324. [Engellwrdtia, Pachira-type, Pelliciem, Podocarpus, Rlrizophom.] _ Lesquereux, L., 1887. List of recently identified foss il plants belonging to the U.S. Nationa l Museum, with descriptions of several new species. Proc. U.S. Nat/. Mus., 10:2 1-46. [List includes specimens possibly o f J urassic age from. Mexico (Mexico, D .F. ?): Calamites approximatus var. cmciatus Lesq., Cladophlebis ( Pecopteris) powefli Lcsq., Cordaites sp.] Lorenzo, J. L., 1958. Una hipotcsis paleoclimatica para Ia Cuenca de Mexico. Miscellanea, Paul Rivet, Octogenario Dicta, Mexico, D.F., 1: 579-584. Maldonado-K oerdell, M., 1947. Estudios etnobiologicos , 3. Contribuciones Mexicanas al conocimiento de Ia etnobiologia del maize y de Ia his Ioria de Ia agricultura en Mexico. An. Just. Nacf. Antropoi.Hist. (Mexico, D.F.),2: 137-14 1. Maldonado-K oerdell, M., 1948. Nota sobre p lantas fosiles del Retico de Ayuquila (Huajuapan de Leon), Oaxaca. Bot. Soc. Geol. Mex.,13: 61-68. Maldonad o-Koerdell, M., 1949. Nueva equisetal del Cretacio superior de Coahuila, Mexico. Bot. Asoc. Mex. Geol. Petrol., I: 27-32. (Neocalamites barcenai Maldonado-K oerdell] Miranda, F., 1963. Two plants from the amber of the Simojovel, Chiapas, Mexico, area. J. Paleontol., 37:611 -614. (Acacia sp. and Tapirira durhamii n. sp. from the Oligo-Miocene of Chiapas, Mexico.] Mullerried, f . K. G., 1933. Estudios paleon tologicos y cstratigraphicos en Ia region de Tehuacan, Puebla. An. Ins/. Bioi. Mex., 4: 33-46. Mullerried, f. K . G.; 1938. Informe del Sr. ... paleontologo del Instituto de Geologia, acerca del material colectad o en el municipio d e Tlacolulan, cstad o de Veracruz. Bot. Soc. Geol. Mex., I 0: 203-206. [Tertiary of Veracruz: Juglans veracruzana Mullerricd.) Mullerried, F . K. G., 1947. Paleobiologia de !a caliza d e Cordoba y Orizaba, Veracruz. An. lnst. Bioi. Mex., 17:361-462. Nathorst, A., 1899a. Fossile Holzer von Tlaco1ula. In: J. Felix und H. Lenk, Beitriige Geologie und Paleontologie der R epubfik Mexiko, Tei/2. Felix, Leipzig, pp. 46-51. Nathorst, A., 1899b. Pflanzenresten aus dem Neocom von llaxiaco. In: J. Felix und H. Lenk, Beitriige Geologie und Paleontologie der Repubfik Mexiko, Tei/2. Felix, Leipzig, pp. 51-54. [Authorship of two above articles unclear from original publication; e.g., Nathorst, or Felix and Nathorst. See also Felix and Nathorst, 1893.] Newbercy, J. S., 1876. Descriptions of the Carboniferous and Triassic fossils collected on the San

LITERATUR E ON VEGETATIO NAL HISTORY IN LATIN AMERICA

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Juan exploring expedition under Captain J. N. Macomb, U.S. E ngineers. Rep. E.1p. Exped. Sama Fe, N.M . to junction Gmnd-Green Ril'en, etc., pp. 135-148. [A>·terocarpu.>/tlfcatus (Emmons) Fontaine, A. ll'hitneyi Newberry, Baiera radiata Newberry, M acroweniopteris cfcgans Newberry, M. magnifo/ia Rogers, Mertensides bullatus Bun bury, M. mexicam1s Newberry, Otozmnites macombii Newberry, Podozamites? crassifolia Newberry, Pterophylfwn fwgile Newberry, P. robus11m1 Newberry, Raphae/ia? remondi Newberry, Taeniopteris glossoptervides Newberry.] Nee, A. C., 1931. Review of American coal-ball studies. Trans. Iff. Acad. Sri., 24: 317-320. Po tonie, R ., 1938. Bcricht iibcr die mikropalacont ologische Untersuchung von Proben aus dcm siidostlichcn Mexiko. R. Dutch Sheff ( Mexiko), Unpubl. Rep. Schulman, E., 1943. The Possibilities of Dendrochronology in Mexico. El Norte de Mexico y e/ Sur de Es1t1dos Unidos (l'ubl. porIa Soc. Mcx. Antropol. Mexico, D. F.), 362 pp. Schwab, K . W., 1969. Calcareous red a lgae from the vicinity of Puerto Penasco, Sonora, Mexico. M orphology of Lithophy/lumm af/escens (Foslie) Heyd rich. J. Ariz. A cad. Sci., 5: 189-193. Sears, P. D., 1947. Notes on correla ted pollen p rofiles and glacial substages. Rev. Mex. Estud. Antropo/., 9: 165- 168. Scars, P. B., 1951. Pollen profiles and cttlture horizons in the Basin of Mexico. 29th Int. Congr. Americanists, Univ. Chicago, Proc., I : 57-61. Scars, P. B., 1952. Palynology in southern North America. I. Archeological horizons in the Basins of Mexico. Buff. Geol. Soc . Am., 63 : 241 -254. Sears, P. B., 1953. T he interdependence of a rcheology and ecology, .1.vith examples from Middle America. Trans. N.Y. Acad. Sci., 15: 113- 117. Sears, P. B. and C tisby, K. H., 1955. Palynology in southern North America. 4. P leistocene climate in Mex ico. Buff. Geol. Soc. Am., 66 :521 - 530. Silva- Pineda, A., 1961. F lora fosil de Ia formacion Santa Clara (Carnico) del estado de Sonora. In: Paleonto/ogia del Triasico Superior de Sonora. Paleontol. Mex. (Unit•. Nac/. Autonoma Mex., lus t. Gevl. ), 1I : 36 pp. (Asterocarpus p/atyrachis fontaine, Tlwwnatopteris sp., cf. T . barrea/ensi.1· Stipanicic y Menendez, M ertcnsides b1dlatus (S unbury) f ontaine, Cladophlebis roesserti (Prest) Saporta, Alethopteris whitueyiNewb erry, Cteuophyllum bratmianwn angustum (Braun) Schimper, Taeniopteris magnifolia Rogers, T. auricula/a (fontaine) Berry, Ptaophyllum fmgile Newberry, P. affine Na!horst, Zamites sp., cf. Z.megaphy/lu s( Phillips) Seward, Z. tnmcatus Zeiller.] Silva-Pineda, A., 1963. Plantas del Triasico superior del cstado de Hidalgo. Paleontol. Mex.,l2 pp. Silva-Pineda, A., 1970a. Plantas fos iles del J urasico medio de Ia region de Tezoatlan, Oaxaca. In: L. R. Segura, y R. Rodriquez-Tor res, Libro-guia de Ia Excursion M exico-Oaxaca. Soc. Geo/. Mex ., pp. 129-143. Silva-Pineda, A., 1970b. Plantas del Pensilvanico de Ia region de Tehuacan, Puebla. Paleoutol. Mex., 29: 1-47. Silva-Pineda, A ., 1970c. Planias fosiles del Jurasico medio de Tecomatlan, Estado de Puebla. Paleontol. Mex., 27: 1- 38. Soloranzo, M. M. and Hobson, B., 1907. Plant rema ins in basalt; Mexico. Geol. Mag ., 4: 217-219. Steimann, G. , 1899. Dber fossile Dasycladaceen von Cerro Escamela. I n: J. Felix, und H. Lenk, Beitriige Geologie und Paleontologie der Republik Mexiko, Teil 2. Felix, Leipzig. pp. 187-204. (See also Bot. Z. , 57 : 137-154). [Triploporeffafraasi, T.fraasi var. minor, Neomeris ( Herouvalina) cretacea, described as sp. nov.] Villada, M. M., 1897. Catalogo de Ia Coleccion de Fosiles del Museo Nacional, M exico, D.F., 80 pp. Villada, M. M., 1903. Consideracioncs sobre Ia flora fosil del Valle de Mexico. An. Mus. Nacf. Mex., 7: 452-454. Villada, M. M., l 914. Breves apuntes acerca de Ia pa!eobiologia del Valle de Mexico. La Naturaleza, 1: 7-13. Ward, L. F., 1889. The geographical distribution o f fossil plants. 8th Atm. R ep., U.S. Geol. Surv., / 886/1887:663 -960. [Cladophlebis (Pecopteris) nov. sp.? (Fontaine in Ward) listed for beds of possible J urassic age from Mexico, D.F.? with Ctenophyllum grandifolium F ontaine (in Ward), C. herrarae Fontaine (in Ward), C. robustum Emmons (Fontaine in Ward), C. cf. C. emmonsi F ontaine (in Ward).] Wieland, G. R., 1909. The Williamsonias of the Mixteca Alta. Bot. Gaz., 48:427-441.

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LITERAT URE ON VEGETATIONAL HISTORY IN LATIN AMERICA

·I

Wieland, G . R., 1910.1nvestigationso n American fossil cycads. Carnegie /nst. Wash . Yearb., 8:231- 232. Wieland, G. R., 1911 a . Continua tion of investigations on fossil cycads. C(llnegie bat. Wash. Yem·b., 9:229- 230. Wieland, G. R., 1911b. On the Williamsonia tribe. Am. J. Sci., Arts, 32:433-466. Wieland, G. R., 1912. La no ra fosil de Ia Mixtcca Alta. Bal. Sec. Geol. Mex., 8: 8. Wieland, G. R., 1913. The Liassic flora of the Mixteca Alta of Mexico; its composition, a ge, and source. Am. J. Sci., Arts, 34: 25 1-28 1. Wieland, G. R., 1914. La flora Liassica de Ia Mixtcca Alta . Bal. fnst. Geol. Mex., 31: 1- 165. [Jurassic of Oaxaca: Angiopteridium? oaxaceusis Wieland, Anomozamites cf. A. lindleyamrs Schimper, Araucarioxylon mexicammr Wieland, Cladoplrlebis albertsii Dunker, Couiopteris. cf. C. hymeuophylloides Brong., Cycadeaspermum oaxacensc Wiela nd, Cycadolepis mexicana Wieland, Equisetites gumbeli Schenck, Glossopteris? lineoris McCoy, G.? mexicanus Wieland, Laccopteris?sp., Macrataeniopteris toukineusis Zeiller, M. cf. M. darweoides Royle, Neoggerathiopsis /rislopi Bunbury, Otozamites (Otopteris) cf. 0. bucklandi Schenck, 0. aguilarianus Wieland, 0. agui/eraiWieland, 0. cardiopteroides Wieland, 0. diazii Wieland, 0. hespera Wieland, 0. hespera var. intermedia Wieland, 0 . hespera var. /atifo/ia Wieland, 0. jrrarezii Wieland, 0. moliniamrs var. oaxacensis Wiela nd, 0. oaxaceusis Wieland, 0. obtusus var. /iassicus Wieland, 0. paratypm Wieland, 0 . reglei var. /ucerensis Wieland, 0. reg/ei var. aaxacensis Wieland, 0. tribu/asus Wieland, 0. cf. 0. abwsus var. oolitica Seward, P!toenicopsis? sp., Pterophyllum angustifolirrm Leckhy, P. cf. P. corrtignum Schenck, P. cf. P. 11111/ISteri Pres!., Ptilopltyllum acutifolium Morris, P. acutifolium var. minor Wieland, P. e.ulc!terrium Wieland Rlwbdocarpus? graudis Wieland, Sagenopteris emmonsi var. mexicaua Wieland, Sphenopteris a.ffinis Lindley and Hutton, Taeuiopteris cf. T. l'illata Brong., Trignocm·prts oaxace11sis Wieland, Williamsonia centeotl Wieland, W. cuauhtemoci Wieland, W. ? huitzilopoc!ttli Wieland, W. ipa/rremoani Wieland, W. quetzalcoatl Wieland, W. mexicana Wieland, W. nathorstii Wieland, W. netzalrualcoyotl Wieland, W. tetcotzoncatl Wieland, W.tlazolteotl Wieland, W. xicotencatli, W. xipe Wieland, W. sp. I, 2, Yuccites oaxpcensis Wieland, Y.? sc/rimperiawrs Zigno?] Wieland, G. R., 1916a. American fossil cycads, 2. Taxonomy. Camegie lnst. Wash. Pub/., 34: 277 pp. Wieland, G. R., 1916b. Conti nuation of investigations on fossil cycads. Carnegie Ins/. Wash. Yem·b., 14:387. Wieland, G. R., 1926. The El Consuela cycadeoids. Bot. Gaz., 81 : 72-86.

Paleobotany of Central America Bartlett, A., 1967. Palynological Studies of Gatun Basin, Panama. PhD. Thesis, Harvard Univ. (Cambridge), 125 pp. Bartlett, A., Barghoorn, E. S. and Berger, R., 1969. Fossil maize from Panama. Science, 165: 389-390. Berry, E. W., 1914. Fossil plants in the Panama Canal Zone. Science, 38:357. Berry, E. W., 191 8. The fossil higher plants from the Canal Zone. In : Contributions to the Geology

and Paleontology of the Canal Zone, Panama, and Geologically Related Areas in Central America and the West Indies. Bull. U.S. Nat/. Mus., 103: 15-44. (Banisteria praemmtia sp. nov., Calyptrant!tes gatunensis sp. nov., Cassia culebrensis sp. nov., Diospyros macdoualdi sp. nov., Ficus culebrensis sp. nov., Guatteria culebrensis sp. nov., Hieronymia /elrmarmi Engelhardt?, Hiraea oligocaenica sp . nov., fuga oligocaenica sp. nov., Melastomites miconioides sp. nov., Mespi/odaplme culebrensis sp. nov., Myristicoplryllum pauamense sp. nov., Palmoxylotz palmacites (Sprengel) Stenzel, Rondeletia goldmani sp. nov., Rubiacites ixoreoides sp. nov., Sc/rmidelia bejucensis sp. nov., Taenioxylon multiradiatum Felix.] Berry, E. W., 1921a. Tertiary fossil pla nts from Costa Rica. Proc. U.S. Nat!. Mus., 59: 169-185. [Anona costaricana sp. nov., Buttneria cinnamomifolia Engelhardt?, Ficus talamancana sp. nov., Goeppertia tertiaria sp. nov., Heliconia sp., Hieronymia /elrmamri Engelhardt?, fuga slzeroliensis sp. nov., Nectandra areola/a Engelhardt, N. woodringi sp. nov., Phyllites costaricensis sp. nov., Piperites cordatus sp. nov., P. quinquecostatus sp. nov.] Berry, E. W., 1921 b. A palm nut from the Miocene of the Canal Zone. Proc. U.S. Nat/. Mus., 59:

325

Berry, E. W., 1942. Mesozoic a nd Cenozoic plants of South America, Central America a nd the Antil les. 8th Am. Sci. COII!;r. (Washington, D.C., 1940) , Proc., Vol. 4 ( Geol. Sci.): 365- 373. Brown, R. W., 1947. Fossil plants and human footprints in Nicarag tra . J. Paleontol., 21: 38-40. [Prioria tu.fficofa sp. nov. (Lcguminosac; Quaternary in age).) Couper, R. A., 1964. Spore- pollen correlation of the Cretaceous rocks of the northern and southern hemispheres. Soc. Econ. Paleonto/. Min., Spec. Pub/., I I : 131- 142. Cowgill, U . M. and Hutchinson, G. E., 1966. La Aguda de Ia Santa Ana Vieja: The history of a pond in Guatemala. Arch. Hydrobiol., 62 : 335- 372. Cowgill, U. M. et al., 1966. The history of Laguna de Petenxil, a small lake in northern Guatemala. Mem. Conn. Acad. Arts Sci., 17: 1-126. (See Tsukada, 1966 for list of pollen types recovered). Howe, M.A ., 1918. Contributions to the geology and paleontology of the Canal Zone, Panama-On some fossil arid recent Lithothamnicae of the Panama Canal Zone.· Bull. U.S. Nat/. Mus., 103: 1- 13. Johnson, J. H . and Konishi, K., i 960·. An interesting late Cretaceous calcareous alga from Gua temala. J. Pa/eamo/., 34: 1099- 1105. J ohnson, J. H . and Kaska, H. V., 1965. Fossil algae from Guatemala. Prof Con/rib., Colo. Sclr. Mines, I : 152 pp. Newberry, J. S., 1888. Rhaetic plants from H onduras. Am. J. Sci., 136 : 342- 351. [Zamites (Pteroplryllum) rolkeri Newberry, Z. (Otozamites) leggetti Newberry, Otozamites ./inguiformissp. nov., Taeniopteris glossopteroides Newberry, Enceplwlartos? denticnlatus sp. nov., Splrenozamites robus/Us sp. nov., S. ? grandis sp. nov., Anomozamitcs e/egans sp. nov., Pteroplry/lum propitUJIIUm Goeppert, P. bmwrsii? Schenk., Dioonites longrfolirrs? Emmons, D. camallianus? Goeppert, Nilssonia polymorplra Nathorst, Noggemthiopsis sp.] Olson, E. C. and McG.rcw, P. 0., 1941. Mammalian fau na from the Pliocene of Honduras. Bull. Geol. Soc. Am., 52: 1219- 1244. , [Mentions an associated flora of wood and leaves (Darrah identifications): Sclrmidelia (Sapindaceae), Gyminda (Celastraceae), Leguminosae, Palmae, Gramineae.] Tsukada, M., 1965. Late Pleistocene palynology in Central America. Congr. Int. Qrratemwy As>·oc., 7th, Boulder, Colorado, /965, Rep., p. 472. Tsukada, M., 1966. The pollen sequence. In: C owgill, U.M. et al., The history o[Lagzma de Petenxil, a small lake innorthem Guatemala. Mem. Comr. A cad. Arts Sci., 17:63-66. [Podocarpus, Acacia, Achras, Alnus, Ambrosia type, Bombax, Bursera, Haematoxylon, Carpinus, Caryophyllaceae, Celtis, Chaetoptelea, C henopodiaceae, Citms type, Coccoloba, Cornpositae, Cyperaceae, Euclrlaena type, Eugenia, Gr amineae, flex, Liquidambar, Luehea, Malpighiaceae, .Moraceae, M)!rica, Myrtaceae, Nymphaea, Pa lmae, Potamogetorr, Quercus, Sapotaceae, Solannm, Spondias, Terminalia, Trema, Typha, Ulmaceae, Vitis, Zamhoxylum, Zea mays type, Zuelania.] Tsukada, M. and Deevey, E. S., 1962. Quaternary palynology in Central America. I. Guatemala n area. Jnt. Conf. Palynology, 1st, Tucson, 1962. Abstr., Polleu Spores, 4: 385. Tsukada, M. and Deevey, E. S., 1967. Pollen analyses fro m four lakes in the southern Maya area of Guatemala and El Salvador. In: E. J. Cushing and H. E. Wright (Editors), Quatemary Paleoecology. Yale Univ. Press, New Haven, pp. 303-331. [Pi11us, Podocarpus, Alchomea, Alnus, Araliaceae, Bursera, Ceiba, Celtis, Chaetoptelea, Chenopod iaceae-Amaranthaceae, Compositae (incl. Ambrosia), Cyperaceae, Gramineae, Hedyosmum, He/iocarpus, Liquidambar, Malpighiaceae, Moraceae, Palmae, Quercus, Sapium, Sapotaceae,

Solanum, Trema, Zea.]

Vo n der Brelie, G. and Teichmuller, M., 1953. B eitrage zur Geologie El Salvador. 3. M ikroskopische Beobachtungen an Mangrove-Sedimenten aus El Salvador. Neues Jahrb. Geol. Palaeontol., 6: 244-25 1.

Paleobotany of the Antilles

21 - 22.

[lriartiles vauglumisp. nov.] Berry, E. W., 1928. A palm fruit from the Miocene of western Panama. J. Wash. Acad. Sci., 18:455457. (Palmocarpon geo1wmoides sp. nov., Chiriqui Province, Panama.)

Anonymous, 1818. Pet rified wood from Antigua. Am. J. Sci., 1:56-57. [Mentions occurrence of fossil wood in Antigua, but no identifications are given.] Ayala-Castanares, A, 1959. Estudio de algunos microfosiles planctonicos de las calizas del Cretacico

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LITERATUR E ON VEGETATIO NAL HISTORY IN LATIN AM ERICA

su perior de Ia Republica de Ha iti. Paleomol. Mex. {Unil•. Nod. Au/on. Mex.• 1!1.1'/. Ceo/.), 4: ..J - 41. [Records fossil algae o f the fa mily Dasycla daceae. ) Beckmann, J. and Beckmann, R., 1966. Calcareous a lgae from the Cretaceous and Tertiary of Cuba . Schwciz. Palaomol. Abh., 85 : 1~5. Berry, E. W., 1921. Tertiary fossil plants from the Dominican Republic. !'roc. U.S. Nat/. Mm., 59: 117- 127. [Bucida sanclu:zeusis sp. nov., Bumclia recliuawfolia sp. nov., Calyptra111he:; domiugeusis sp. nov., Guellardia caokei sp. nov., Juga stmchezensis sp. nov., fuga sp., Mela.rtomires domingeusis sp. nov., M. sp., Pisouitl conditi Berry, Pilhecolobium samm1en•i.1· sp. nov., Poacitcs sp., Sapind11.1' hispaniolana sp. nov., Sophora cookei sp. nov.] Berry, E. W., 1923. Tertiary fossil pla nts from the Rep ublic o f Haiti. Pmc. U.S. Nail. Mus., 62: 10 pp. [Cham woodringi sp. nov., Gymnogramme woodringi sp. nov., Bamelia cuuea/afolia sp. nov., ChryJ·ophyllum cahobascnsis sp. nov., Guellarda cookci Berry, Mespilodap/me hiJ1Jtllliolaua sp. nov., Mimusops praeparvifolia sp. nov., Pisonia coudiliBcrry, Simaruba haiJeusis sp. nov.] llerry, E. W., 1934. Pleistocene plants from Cuba. Bull. Torrey Bot. Club, 61:237-240. [Juniperus sp., Pinus caribaea Morelet, Chrysoba/anus icaco L., Conocatplls sp., Mim11sops emargiuata (L.) Britton , Spoudias /uJea L.] Berry, E. W., 1939. A M iocene flora from the gorge of the Yumari River, Ma tanzas, Cuba. Johns Hopkins Univ. Slud. Geol., 13:95- 135. [G/eic!tenia pectiuataformia sp. nov., Anl!tolilhfls heimiaformis sp. nov. (fncertae sedis), Bignonia z11liaua Berry, Bmnelia relusafolia sp. nov., Caesalpinia prebahamensis sp. n ov., Caesa/piuiles incerlfls sp. nov., Calophyllum ca/abaformis Berry, Capparis prejamaicensis sp. nov., Cassia yuttull·iensis sp. nov., Celas/rus simplex sp. nov., Dalbergia hesperia sp. nov., Dodottaea cubensis sp. nov., Drypeles laterif/oraforma sp. nov., Eugenia o••atifolia sp. nov., Exoslema precaribaeum sp. nov., Fagara miocenica sp. nov., Helicouia sp., Juga leonii sp. nov., I. miocenica sp. nov., Laguncularia racemosafolia sp. nov., Metopium premmlium sp. nov., Mimusops leonii Hollic k, M. miocenica Berry, Myrcia minor sp. nov., M. prerostmw sp. nov., Pisouia longifo /iaformis sp. nov., Pithecolobium yumuriensis sp. nov., Pse11tlolmedia spuriaformis sp. nov., Reynosia latifolioides sp. nov., Rheedia silvargillacea Berry, Sapitulas presaponaria sp. nov., Simaruba glaucaformis sp. nov., Sophora martmoides sp. nov., S. matanzaua sp. nov. , S. ywnuriensi.1· sp. nov., Swielenia mahagouiformis sp. nov., Trichilia hirlaformis Berry, Zizyphus elliplica sp. nov., Z. mitwr sp. nov.] Berry, E. W., 1942. Mesozoic and Cenozoic plants of South America, Central America and the Antilles. Proc. A111. Sci. Cougr. 8111, Wash. D.C., 1940,4:365-373. Felix, J., 1883. Die fossile Holzer Westindiens. Samml. Palaonlol., Ser. 1(1): 22-27. Ga lles, P. P., 1887. Memoria sob re unos fosiles vegetates encontrados en el Chorillo (Puerto Principe) por el Padre Pio Galtes. Puerto Principe, Imp. El Fanal, 19 pp. Graham, A. and Jarzen, D. M., 1969. Studies in Neotropical Pa leobotany. I. The Oligocene communities of Puerto Rico. Ann. Mo. Bo1. Gard., 56:308-357. [Cyathea, Hemilelia ( Cuemidaria), Jamesonia ( Eriosorus), Lycopodium A, L. B., Pteris, Selagi-

327

Hodge, E. T ., I 920. Geology o f the Coamo- Guayama District. N. Y. Acad. Sci. Sci. Sufi'. Poria Rico and Jhe Virgin fslands, I : 111 - 228 . Hollick, A., 1924. A review of t he fossil flora of the West Indies, with descriptions of new species. N.Y. Bot. Gard. Bull., 12: 259-323. Hollick, A., 1926a . Paleobotanical exploration in Puerto Rico. J. N.Y. Bot. Gard., 27: 102-1 04. Hollick, A., 1926b. Fossil walnuts and lignite from Puerto Rico. J. N.Y. Bot. Gard., 27: 223- 227. Hollick, A., 1928a. Paleobotany o f Porto Rico. N.Y. A cad. Sci. Sci. Surv. Poria Rico and the Virgin Islands, 7: 177-393. [Acrodic/idium pseudocanelo sp. nov., A. pseudosalicifolium sp. nov., A11iba co/lazoensi~· sp. nov., Annona cetera >p. nov., A. pseudoglabra sp. nov., Apocyuophyllum pseudowillughbya Ho llick, A. wilcoxense Berry?, Aspidosperma co/lazoensis Hollick, Baclt'is pseudocuesco sp. nov., Cassia(?) dubiosa Hollick, C. evidens sp. nov., C. imilaliva sp. nov. , C. imparilis sp. nov., C. ordinaria sp. nov., C. puryearensis Berry, C. vi.1·ibilis sp. nov., Chondrites diclyotoideJ·, Chrysophyllum comparabile sp. nov., C. pseudargenleum sp. nov., C. pseudargenteum oblongum n. va r., Combrelum pseudojacquini i sp. nov., Copaiva oligocenica sp. nov., Cynomelra rabellii sp. nov., Dipholis pseudoleiautha sp. nov., Ec/ritonium? sp., Echite.1· pseudosJel/aris sp. nov., Eugenia comparabilis Hollick, E. pseudoaeruginea s p . nov., Ficus hyplwdroma sp. nov., F. schimperii l esq., F. vexalii'IIS sp. nov., F. sp., Guarea opinabilis sp. nov., Guellarda intercalaris sp. nov., Hancomia minor Hollick, H. pseudopubescen:; Hollick, Hemilelia brannerii H ollick, and Berry, Hufe/audia portoricensis (Hollick) n. comb., Jcacorea prisca Hollick, f .? sp., Juga curta sp. nov., f. pseudinsit niss p. nov., !. pseudonobilis Hollick,/. pseado~1juria sp. nov., 1.? sp. Hollick, lriartea collazoensis sp. nov., Isoetes? incerla sp. nov., Lanchocarpus praelmifolius sp. nov., Malvocarpo11 clarum gen. ct sp. nov., Manicaria porloricensis sp. nov., Melicocca immutata sp. nov., M. sp., MiJcmteca dabio.w (Hollick) n. comb., Musophyllwn sp., Myrcia detumtiativa sp. nov., M . eugenioides Hollick, Myrsine pseudofermginea sp. nov., Oreodaplme mississippi?mis Berry?, Palmocarpo 11 acrocomioides Hollick, P. eelera sp. nov., P. exemplare sp. nov., P. opinabi/e sp. nov., P. rabellii sp. nov., Palmacites alias sp. nov., P. conformL~ sp. nov., P ..1parsistriatus sp. nov., Palmophyllwn sp. Ho llick, P. sp. (fra gment of petiole)? H ollick, Pilhecellobium? imperfeclwn sp. nov., P. pseudo trapezifolium Hollick, P. vexalivum Ho llick, Plumiera evidens Hollick, Psidium dissimile sp. nov., P. ?sp. Hollick, Ramulus gen.et sp. ?, Rhizophora?doctrina/issp. nov., Sapolaagnitionalis sp. nov., Sapindus brillonii sp. nov., S . gracilemus sp. nov., S . obesus Hollick, S. pseudomarginatussp. nov., Sophora? suspec/a Hollick, Sideroxylon aequale sp. nov., Trichi/ia evide11s sp. nov., T. pseudobakerii sp. nov., T. pseudolrirta sp. nov., T. spttlulala sp. nov., Zamia collazoensis sp. nov., Z. noblei sp. nov., Zizyplws pseudochlorox y/on sp. nov.] Ho llick, A., 1928b. Conference notes (Pleistocene plant remains fro m Cuba, and a new method of illustrating identifications o f fossil leaf remains). J. N.Y. Bol. Gm7d., 29: 115- 116. Howe , M. A., 1919. Tertiary calcareous algae from the islands of St. Ra rtholemew, Antigua a nd Anguilla . Camegie lust. Wash. Pub/., 291 :9-19. Kaul, K . N., 1943. A palm stem from the Miocene of Antigua, W.l.-Phyleleph as sewardii sp. nov. Proc. Linn. Soc. Loud., 155: 3~. ["T he only other record of fossil Phytelephas, however, is part of a stem from the Miocene o f Antigua, described as P. sewardii Kaul, and now in the Natural History Museum, South Kensington, London."(Bro wn, 1956).] Lemoine, M. P., 1917. Corallinacees fossiles de Ia Martinique. I. Algues du Miocene inferieur. Bull. Ceo/. Soc. Fr., 17: 256-279. Leon, H., 1929. La fl ora fosil de Cuba, en le actualidad. Soc. Geogr. Cuba Rev., 2: 22- 27. Lo ubiere, A., 1940. Sur un bois silicifie de monocotyledones du Tertiaire des Antilles. Mus. Hist. · Nat . Paris Bull., 12: 177-179. Margo lis, S. and Rex, R. W., 1971. E ndolithic algae, and micrite envelope formation in Bahamian oolites as revealed by scanning electron microscopy. Bull. Geol. Soc. Am., 82: 843-852. Maury, C. J., 1930. Correlation of Antillean fossil floras. Science, 72: 253- 254. Ogle, C. J ., 1970. Pollen analysis of selected Sphagnum-bog sites in Puerto Rico. Jn: H. T. Odum (Editor), A Tropical Rain Forest. Div. Tech. Inform., U.S. A. E. C., Oak R idge (fenn.), pp. Bl35BI45. [Lycopodium, Polypodiaccac-Cyatheaceae, Selaginel/a, Alchornea, Buchenavio, Casuarina, Clusia, Compositae, Cordia, Croton, Cyrilla, Dacryodes, Didymopanax, Ericaceae, Eugenia, Gram ineae,

nella, Podo~arpus, Abutilon, Acacia, Aelantlws, Alchom ea, Bem oullia, Bombax, Brunellia, Bursera, Casearia, Catostemma, Chrysophyllum, Coryuosly/is, Dendropauax, Eugelltardtia, Eugenia, Fagus, Faramea, Gum·ea, Hauya, flex, Jacaranda, Liquidambar, Marcgravia, Merremia, lvfyrica, Norantea, Nyssa, Oxalis, Palmae, Pelliciera, Pleodendt·ou, Rauwolfia, Rhizophora, Salix, Tecoma, Tetrorchidiwn, Toumefortia, Zanthoxyltlm.] H abib, D., 1968. Palynology of the San Sebastian coal (Oligocene) of Puerto Rico. Abstr. 5th. Carib. Geo/. Con[. Univ. P.R., Mayaguez,pp. 35-36. Hodge, E. T., 1917. Geology of the Coamo-Gyaya ma region, Porto Rico. Am1. N.Y. Acad. Sci., 27 : 277-278. ["The earliest published references to fossil plant remains in Po rto Rico were by H odge, who mentioned the presence of a bed of limestone, and an adjacent bed of hematite containing fossil leaves, in the northeastern part of the region discussed. T he beds were inferred to be lower Cretaceous, by reason o f a characteristic species of coral found in the limestone, and from the general facies of the flora as indicated by a few plant remains found in the hematite bed." (Hollick, 1928, p. 177)]

A. GRAHAM

LITERATURE ON VEGETATIONAL HISTORY IN LATIN AMERICA

Hedyosmum, flex, Liliaccac, Moguolia, Microp!Jolis, Palmac type, Rutaccac type, Selagine/la, S/oanea, Tabebuia.] Sanderson, M. L. and Farr, T. H., 1960. Amber with insect and plant inclusions from the Dominican Republic. Science, l31: 1313. ("Fragments of wood, roots, fl owers, leaves ... "; no specific plants named.] Stenzel, K. G. W., 1897. Palmoxylon iriateum n. sp., ein fossiles Pa lmholz aus Antigua. Kg/. S••ensk. Vet. Akttd. Hand/., 22: 1-17. Traverse, A. and Ginsburg, R . N., 1966. Palynology of the surface sediments of the Great Bahama Bank, as related to water movement and sedimentation. Mar. Geol., 4: 417-459. Weinstein, D. A., 1969. Palynology of the £an Sebastian coal (Oligocene) of Puerto Rico. Abstr., 3al Atm. 1'vfeeting South-Centro/ Sect., Geol. Soc. Am., T.awrence, Kansas, p . 33.

Archangclsky, S., 1965d. Tafofloras Palcozoicas y Eomcsozoicas de Argentina; Analisis de sus componcntcs y vinculacioncs con otras tafofloras coctancas extraargentinas. Bot. Soc. Argent. BoT., 10: 247-29 1. Archangelsky, S., 1966. New gymnosperms from the Tico flora, Santa Cruz Province, Argentina. Bull. Brit. Mus. Nat. Hist., 13:259-295. Archangelsky, S., 1967. Estudio de Ia Formacion Baquero, Cretacco Inferior de Santa Cruz. Rev. Mus. Ptdeomol. Univ. Nacl. La Plata {Argentina), 5:63- 171. Archangclsky, S., 1968a. Sobre el palcomicroplancton del Terciario inferior de Rio Turbio, Provincia de Sarita Cruz. Amegltiniana, 5:406-416. · Archangclsky, S., J968b. Palaeobotany and palynology in South America: A Historical review. Rev. Palaeobot. Palynol., 7 : 249-266. Archangclsky, S., 1968c. On the genus Tomaxellia (Conifcrae) from the lower Cretaceous of Patagonia (Argentina) and its male and female cones. In: K. L. Alvin, P. D. W. Darnard and W. G. Chaloner {Editors), Studies on Fossil Plants. Academic Press (London), pp. 153- 165. Archangelsky, S., 1968d. Notas sobre Ia flora fosil de Tico. 8. Seis espccics de Sphenopteris. Ameghiniana, 5: 149-157. Archangelsky, S., 1968e. Studies on Triassic fossil plants from Argentina. 4. The leaf genus Dicroidium and its possible relation to Rhexoxy/on stems. Palaeontol., 11: 500-512. Archangelsky, S., 1968f. Permian and Triassic floras of South America . l//SI. Geol. Acad. Sci. U.S.S.R., 191:71- 87 Archangelsky, S., 1969. Estudio del paleomicroplancton de Ia Formacion Rio Turbio (Eoceno) Provincia de Santa Cruz. Amegltiniona, 6: 18 1-218. Archangclsky, S., 1970. Fundamentos de Paleobotanica. Fac. Cient. Nat. Mus. Univ. La Plata, Ser. Tee. Didact., 10: l- 347. Archangclsky, S. and Arrondo, 0. G., 1965. Elementos ftoristicos del Permico Argentino. I. Las Glossopteridcas de Ia scric Nueva L~bccka, Provincia de Chubut. Rev. Mus. Paleontol., Univ. Noel. La Plata ( Argemina), 4: 259-264. Archangelsky, S. and Arrondo, 0. G., 1966. Elementos flo risticos del Permico Argentino. 2. Rltacopteris c/wbutiana n. sp. Re1•. Mus. Paleontol., Univ. Nacl. La Plata (Argentina), 5: 1-16. Archangelsky, S. and Arrondo, 0. G., 1967. T he Permian Tafoflora of Argentina, with some considerations about the presence of "northern" elements and their possible significance. illf. Union Geol. S ci., Gondwana Symp. {B. Aires, Oct., 1967), pp. 71- 89. Archangelsky, S. and Bonetti, M., 1963. Fructificaciones de Glossopteridcas del Permico del Bajo de La Leona, Provincia Santa Cruz. Amegltiniana, 3: 29-34. Archangelsky, S. and Brett, D. W., 1960. Nota preliminar sobrc el hallazgo de Rhexoxylon en Ia cuenca de Ischigualasto, limite de las Provincias de San Juan y La Rioja. Lilloaua, 3: 187-190. Archangelsky, S. and Brett, D. W., 1961. Studies on Triassic fossil plants from Argentina. I. Rltexoxylon from the Ischigualasto F ormation. Philos. Trans. R. Soc. Loud., 244: 1-J 9. Archangelsky, S. and Brett, D. W., 1963. Studies on Triassic fossil plants from Argentina. 2. Michelilloa waltonii nov. gen. et sp. from the lschigualasto Formation. Atm. Bot., 27: 147-154. Archangelsky, S. and De Ia Sota, E., 1960. Contribucion al conocimiento de las filices Permicasde Patagonia extraandina. Lilloana, 3: 85-126. Ar(;hangelsky, S. and De Ia Sota, E., 1962. Estudio anatomico de un estipite petrificadode Osmundites, de edad J urasica, procedente del Gran Bajo de San Julian, Provincia de Santa Cruz. Amegltiniana, 2: 153- 167. Archangelsky, S. and De Ia Sola, E., 1963. Osmundites lterbstii, nueva petrificacion Triasica de El Tranquilo, Provincia de Santa Cruz. Ameghiniana, 3: 135-139. Archangelsky, S. and De Ia Sota, E., 1966. Estudio anatomico de una nueva Lycopsida del Permico de Bolivia. Rev. Mus. Paleontol., Univ. Noel. La Plata (Argentina), 5:17-26. Archangelsky, S. and Gamerro, J. C., 1965. Estudio palinologico de Ia Formacion Baquero (Cretacico), Provincia de Santa Cruz, I. Ameghiniana, 4: 159- 167. (See also Catalog Fossil Spores Pollen, 33: 29-34). Archangelsky, S. and Gamerro, J. C., 1966a. Estudio palinologico de Ia Formacion Baquero (Cretacico), Provincia de Santa Cruz, 2. Ameghiniana, 4: 201-209. (See also Catalog Fossil Spares Pollen, 33 : 35-43). Archangelsky, S. and Gamerro, J. C., 1966b. Estudio palinologico de Ia Formacion Baquero (Cretacico), Provincia de Santa Cruz, 3. Ameghiniana, 4:229-236.

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Paleobotany of South America Andrews, H. N ., 1950. A.fossil osmundaceous tree-fern from Brazil. Bull. Torrey Bot. Club, 17: 29- 34. Anonymous, 1895. Comentario de un articulo del Dr. F. Kurtz del Gondwana inferior de Argentina (Bajo de Velez). Nature, 52: 523. Anonymous, 1948. Viaje de estud io a los bosques petrificados. Cienc. bn•est., 4: 161. Archangelsky, S., 1955. Sobre Ia flora de Glossopteris y su importancia para Ia Argent ina. Cienc. Invest., I I : 506-508. Archangelsky, S., 1956. Palinologia, una nueva rama, de Ia biologia y palcontologia. Cieuc. Invest., 12: 400-404. Archangclsky, S., 1957. Las Glossopterideas del Bajo de Ia Leona, Provincia de Santa Cruz. Rev. Asoc.Geol.Argent., 12: 135- 164. Archangelsky, S., 1958a. Eremopteris golondrinensis, nueva espccic de Ia seric La Golondrina. Ullaa11a, 2:285-289. Archangelsky, S., 1958b. Estudio geologico y paleontologico del Bajo de Ia Leona (Santa Cruz). Lilloaua, 2:5-133. Archangelsky, S., 1960a. Lycopdisa y Sphenopsida del Paleozoico superior de Chubut y Santa Cruz, Patagonia.Li//oana, 3:21-36. Archangelsky, S., 1960b. Chiropteris hal't'isii, nueva especie de Ia serie La Golondrina, Provincia de Santa Cruz. Lilloaua, 3: 289-293. Archangelsky, S., 1960c. Estudio anatomico de dos especies del genero Abietopitys Krause!, procedentes de Ia serie Nueva Lubecka Provincia Chubut, Argentina. Lil/oaua, 3: 33 1- 338. Archangelsky, S., 1961. Sobre Ia flora de Glossopteris de Bajo de La Leona, Santa Cruz, Patagonia. Ameghiuiana, I :42-43. Archangelsky, S., 1962. Conceptos y metodos en paleobotanica. Univ. Noel. La Plata (Argentina), Ser. Tee. Didact. , 9:34 pp. Archangelsky, S., 1963a. Notas sabre Ia flora fosil de Ia zona de Tico, Provincia de Santa Cruz. Amegltiniana, 3: 57- 62. Archangelsky, S., 1963b. Notas sobre Ia flora fosil de Ia zona de Tico, Provincia de Santa Cruz; 2. Tres nuevas especies de Mesosingeria. Ameghiniana, 3: 113-120. Archangelsky, S., 1963c. A new Mesozoic F lora from Tico, Santa Cruz Province, Argentina. Bull. Brit. Mus. Nat. Hist., 8:45-92. Archangelsky, S., 1964a. Notas sobre Ia flora fosil de Ia zona de Tico, Provincia de Santa Cruz; 3. Ruftoriniapilifera n. sp. 4. Equisetitessp. Amegltittian'a, 3:221-226. Archangelsky, S., 1964b. Notas sobre Ia flora fosil de Ia zona de Tico, Provincia de Santa Cruz; 5. Sphenopteris cf. goeppertiDunker. 6. Cladophlebis sp. Ameghiniana, 3: 280-284. Archangelsky, S., 1965a. Dos nuevas localidades con plantas fosiles del Baqueroense (Cretacico inferior) de Ia Provincia Santa Cruz. Rev. Mus. Paleontol. Univ. Noel. La Plata (Argentina}, 4: 247-257. Archangelsky, S., 1965b. Fossil Ginkgoales from the Tico fl ora, Santa Cruz Province, Argentina. Bull. Brit. Mus. Nat.llist. , 10: 119- 137. Archangelsky, S., 1965c. Notas sobre Ia flora fosil de Ia zona de Tico, Provincia de Santa Cruz; 7. Dos nuevas especies de megasporas. Ameghiniana, 4: 52- 56. (See also Catalog Fossil Spores Pollen, 33: 25-28).

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Archangclsky, S. and Gamcrro, J. C., 1966c. Estudio palinologico de Ia Fonnacion Baquero (Cretacico), Provincia de Santa Cruz, 4. Ameghiuiaua, 4: 363- 372. (Sec also Catalog Fossil Spores Pollen, 33: 44-50). Archangelsky, S. and Gamcrro, J. C., 1967a. Pollen grains found in coniferous cones from the lower Cretaceous of Pa tagonia (Argentina). Rev. Palaeobot . Palynol.. 5: 179-182. Archangelsky, S. and Gamcrro, J. C., 1967b. Spore and pollcr, types of the Lower Cretaceous in Patagonia. Rev. Pa/aeobot. Polyuol., I : 21 1-218. Archangelsky, S., Petriclla, B. and Romero, E., 1969. Nota sobre el bosque petrificado del Cerro Bororo (Terciario inferior), Provincia de Chubut. Ameg/uitiaua, 6 : I 19-126. . Arnold, H. C., 1966. Upper Paleozoic Sabaneta-Palmarito sequence of Merida Andes, Venezuela. Bull. Am. Assoc. Pet. Geologists, 50: 2366- 2387. [Brief mention is made of an occurrence of plant megafossils (no genera given), and "plicate and bisaccatc sporo mo rph types indicates Permian to be the likely age for most of the formation. These forms are absent, however, in the lower part of the section where a variety of trilete spores is presenl. The possibility that the lower part of ti\.C forma tion may be older (Carboniferous) must be recognized until fu rther stLtdy of t he trilete spores has been undertaken" (pp. 2371-2372).) Arrondo, 0. G., 1967. Dizeugotheca brauisae n. sp. Nueve filice eusporangiada del Permico inferior, Bolivia. Re1•. Mus. Paleomo/., Uui v. Naci. La Plata ( Argemiua), 5: 55-61. Aucr, V., 1933a. Verschicbungen der Wald- und Steppengebicte Feuerlands in Postglazialer Zeit. Acta Geogr. ( Helsinki), 5: 3I 3 pp. Aucr, V., 1933b. DC{· To rfund dieTorfschichtenals historische Urkundcn Feuerlands in Postglazialer Zeit. Ceo/. Ruudsch., 32: 4-5. Aucr, V., 1933c. D ie Moore Siidamerikas, insbesonders des Feuerlandes. Handb. Moorkwule, 1. Auer, V., 1941. Der Torf und die Torfschichten als historische Urk undcn Feuerlands und Patagonicos. Geol. Rundsch., 32:647-671. Aucr, V., 1946. T he Pleistocene and Postglacial Period in Fuegopatagonia. Sitz. Ber. Femt. Akad. Wiss., 12: 189- 208 (reprinted as Pub/. lust. Geogr. , Uui v. Helsinkieusis, 12: 189-208). Auer, V., 1948. Las capas volcanicas como nuevo metodo de cronologia Postglacial en Fuegopatagonia. Gaea, 8: 311- 336. (cf. Pub/. hiS/ . Suelos Agrot., 6: 311-336). Aucr, V.,l949. Historia de los bosques Fuego-Patagonicas. Assoc. Fore;·t . Argent. (Buenos Aires), 40 pp. Aucr, V., 1950. Las capas volcanicas como base de Ia cronologia Postglacial de Fuego patagonia. Rev. Invest. Agric., 3: 49-208. (cf. also Pub/. lust. Suelos Agrot., 9: 51 -208). Auer, V., 1951a. Preliminary results of studies on the Quaternary geology of Argentina. Ann. Acad. Sci. Femricae, 25: l - 12. Auer, V., 195 1b. Evo lucion Postglacial del valle inferior del Rio Negro y va riaciones Quaternaires de Ia linea costanera. Rev. Invest. Agric., 5 : 435-464. Auer, V., I 956. The Pleistocene of Fuego-Patagonia. 1. The ice and interglacial ages. Ann. Acad. Sci. Femticae, 45: 1- 226. Auer, V., 1958. The Pleistocene of F uego-Patagonia. 2. The history of the flora and vegetation. Ann. A cad. Sci. Fennicae, 50 : 1-247. Auer, V., 1959. The Pleistocene of Fuego-Patagonia. 3. Shoreline d isplacements. Ann. Acad. Sci. Femricae, 60: 1- 247 Auer, V., 1960. The Quaternary history of Fuego-Patagonia. Proc. R. Soc. Loud., 152: 507-5 16. Auer, V., 1963. Control studies and my journey to Patagonia, 1956- 1957. Terra Finlaudica, 75: 297320. . Auer, V., 1964. Late-glacial and Post-glacial shoreline displacements in South America as established by tephrochronology, compared with displacements in the Baltic shorelines. Fennia, 89: 51-59. Auer, V., 1965. The Pleistocene of Fuego-Patagonia. 4. Bog profiles. Ann. Acad. Sci. Fermicae, 80 : 1- 160. Auer, V., 1970. The Pleistocene of Fuego-Patagonia. 5. Quaternary problems of southern South America. Ann. Acad. Sci. Fenuicae (Geoi.--Geogr.), 100: 1- 194. Auer, V., Salmi, M. and Salminen, K., 1955. Pollen and spore types of Fuego- Patagonia. Ann. A cad. Sci. Fenuicae, 43: 1- 14. Barbosa, 0., 1949. Vegetais fosse is do Devoniano do Brasil e da Bolivia. Eng., Min. Metal. , 14: 81-84. Barbosa, 0., 1950. Nota sobre plantas fosseis de Forma<;ao Cicero Dantas do Cretaceo da Bahia. An. Acad. Bras. Cienc., 22 : 25-28.

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Barbosa, 0 ., 1952. Comparison between the G ondwana of Brazil, Bolivia and Argentina. Symposium sur Ser. Goudwmm, XIX Cougr. Geol. llllem., Algeria, Proc., pp. 313-324. Barbosa, 0., 1953. Sobre a idade das camadas Mcsozoicas do nordeste do Brasil. Nows Prelim., Est. Div. Geol., Min., Agric., Riode J ., 12: 1-19. · Barbosa, 0., 1955. Situa~ao das Charophyta de Machado de Melo, Estado de Sao Paulo. Dol. Soc. Bms. Ceo/., 4: 73-74. Barbosa, 0. , 1957. Obscrva~ao sobre Parataxopitys americana (Milanez et Dolianiti). Dol. Soc. Bras. Ceo/. , 6: 5-6. . . Barbosa, 0., 1958. On the age of the Lower Gondwana floras in Brasil and abroad. Congr. Geo/. llllem. XX, Mexico. Proc., pp. 205- 236. Berry, C. T. , 1934. Pleistocene remains fou nd ncar Lake Tacarigua, Venezuela. J. Waslt. Acad. S ci., 24: 387- 395. [""A remarkable Pleistocene fin d (of charophytes) from northern Venezuela was reported by Ch. T. Derry (1934, p. 390)." (Horn a f Rantzicn, 195 1).] Berry, E. W., 1917. Fossil plants from Bolivia and their bearing upon the age of uplift of the eastern Andes. Proc. U.S. Nat/. Mus., 54: 103-164. Berry, E. W., 1918a. Pa leogeographic significance of the Cenozoic floras of equatorial America and the adjacent regions. Bull. Geo/. S oc. Am., 29: 63 1-636. Berry, E. W., 1918b. Age of certain plant-bearing beds and associated marine formations in South America. Bull. Geol. Soc. Am., 29: 637-648. Berry, E. W., 1919. Miocene fossil plants fro m northern Peru. Proc. U. S. Nat/. Mus. , 55 : 279-294. Berry, E. W., 1920. A fossi l sea bean from Venezuela. Am.!. Sci. , 50: 310-3 13. (Genus Entoda, Leguminosae). Berry, E. W., I921a. Tertiary fossil plants from Venezuela. Proc. U.S. Nat/. Mus., 59: 553-579. - Berry, E. W., 1921b. Tertiary format ions of western South America. Pan-Pacific Sci. Con/. Proc., pp. 845-865. ~ Berry. E. W., 1922a . Carboniferous plants from Peru. Am.!. Sci., 3: 189-194. Berry, E. W., 1922b. Saccoglollis, recent and fossil. Am. J. S ci., 4: 127-130. Berry, E. W., 1922c. Carboniferous plants from Peru. Johns Hopkins Univ. Stud. Geo/., 4:9-44. Berry, E. W., 1922d. The Mesozoic flora of Peru. Jo!tus Hopkins Uttiv. Srud. Geo/.,4: 45-72. Berry, E. W., 1922e. The flora of the Concepcion-Arauco coal measures of C hile. Jolml· Hopkins Uuiv. Stud. Ceo/., 4: 73-144. Berry, E. W., 1922f. Pliocene fossi l plants from eastern Bolivia. Johns Hopkins Univ. Stud. Geol., 4: 145- 204. Berry, E. W., 1922g. Late Tert iary plants from J ancocata, Bolivia. Johns Hopkins Uni v. Stud. Geo/., 4: 205-22 1. Berry, E. W., l922h. Outlines of South American geology. Pan- Am. Geol., 38 : 187-216. Berry, E. W., 1923. Tertiary plants from the An des ofCajamarca, Peru. Am. J. Sci., 5:239-246. Berry, E. W., 1924a. Mesozoic Gleicheuia from Argent ina. Pan-:Am. Geo/.,41: 17-21. Derry, E. W., 1924b. New Tertic species of Anacardiwn and Varitauea from Colombia. Pan-Am. Ceo/., 42: 259-262. Berry, E. W., 1924c. A fossil flower from the M iocene of Trinidad. Am.!. Sci., 7: 103-108. Berry, E. W., 1924d. Mesozoic p1ants from Patagonia. Am. J. Sci., 7: 463-482. Berry, E. W., 1924e. An Oligocene cashew nut from South America. Am. J. Sci., 8: 123-126. Berry, E. W., 1924f. Fossil fruits from the eastern Andes of Colombia. Bull. Torrey Bot. Club, 51:6167. Berry, E. W., 1924g. A fossil Celtis from Colombia. Torreyo, 24: 44-46. Berry, E. W., 1925a. A species of Musa in the Tertiary of South America. Proc. Nat/. Acad. S ci., II: 298-299. Berry, E. W., 1925b. Fossil plants from the Tertiary of Patagonia and their significance. Proc. Nat/. A cad. Sci., 11 :404-405. Berry, E. W., 1925c. Miocene Araceae related to Caladium from Trinidad. Part-Am. Ceo/., 44: 38-42. Derry, E. W., 1925d. A Pleistocene flora from the island of Trinidad. Proc. U.S. Nat/. Mus., 66: 1- 9. Berry, E. W., 1925e. The Quimsa Cruz region of Bolivia. Johns Hopk ins Univ. Stud. Geol., 6:9-28. Berry, E. W., 1925f. The Tertiary flora of the island of Trinidad, B.W.I. Johns Hopkins Univ. Stud. Ceo!., 6 : 71- 162.

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Berry, E. W.,I929b. The fossil flora of the Loja Basin in southern Ecuador.Jo/ms Hopkins Uni•·· Stud. Ceo/., 10: 79- 136. Berry, E. W., 1929c. Early Tertiary fruits and seeds from Belen, Peru. Johns Hopkins Univ. Stud. Ceo/., 10: 137-180. Berry, E. W., 1929d. Fossil fru its in the An con Sandstone of Ecuador. J. Pa/eontol., 3: 298-30 I. Berry, E. W.• 1929e. An Eocene tropical forest in the Peruvian desert. Proc. Nat/. A cad. Sci., 15: 345346. Berry, E. W., 1929f. Eocene p lants from Resting Formation of Peru. Pan-Am. Ceo/., 51: 241-244. Berry, E. W., 1931 . A Bothrodendron from Bolivia. J. Wash. Acad. Sci., 21:295- 298. Berry, E. W., J 932a. Fossil plants from Chubut territory collected by the Scarritt Patagonian Expedition. Am. Mus. No••it., sji;: 1-10. Berry, E. W., 1932b. A new palm from the upper Eocene of Ecuador. J. Wash. Acad. Sci., 22 : 327329. Berry, E. W., 1932c. Sketch of the geology of Bolivia. Pan- Am. Ceo/., 57:241-262. Berry, E. W., 1933a. A Jacaranda from the Pliocene of Brazil. Torreya, 33: 38-40. Berry, E. W., 1933b. A new Lygodium from the Late Tertiary of Ecuador. J. Was/1. Acatl. Sci., 23: 208- 210. Berry, E. W., 1933c. Carboniferous plants interbedded in the marine section o f Bolivia. Am. J. S ci., 25:49-54. Berry, E. W., 1934a. Fossil plants from the Malacatos Valley in southern Ecuador. J. Wash. Acad. Sci., 25: 126-128. _ Berry, E. W., l 934b. Pliocene in the Cuenca Basin of Ecuador. J. Wasil. Acad. Sci., 24: 184-186. Berry, E. W., l 934c. Miocene Patagonia. Proc. Nat/. Acad. Sci., 20:280-282. Berry, E. W., I 935a. Tertiary plants from Brazil. Proc. Am. Pililos. Soc., 75: 565-590. Berry, E. W., 1935b. A T ertiary Ginkgo from Patagonia. Toneya, 35: 11- 13. Berry, E. W., 1935c. A fossil Cochlospermum from northern Patagonia. Bull. Torrey Bot. Club, 62: 65- 67. Berry, E. W., 1936a. Tertiary plants from Colombia. Bull. Torrey ]lot. Club, 63: 53-66. Berry, E. W., 1936b. Tertiary plants from Venezuela. Proc. U.S. Nat/. Mus., 83: 325-360. Berry, E. W., 1936c. Tertiary flora from northern Patagonia. Proc. Geol. Soc. Am. (abstract), p. 357. Berry, E. W.,l937a. Upper Cretaceous plants from Patagonia. Science, 86 :221- 222. Berry, E. W., 1937b. An upper Cretaceous flora from Patagonia. Johns Hopkins Univ. Stud. Ceo/., 12: 11-32. Berry, E. W.,1937c. A Paleocene flora from Patagonia. Johns Hopkins Univ. Stud. Ceo/., 12: 33-50. Berry, E. W., 1937d. A flora from the Forest Clay of Trinidad. Johns Hopkins Univ. Stud. Ceo/., 12: 51- 68. Berry, E. W., 1937e. A late T ertiary flora from Trinidad, B.W.I. Johns Hopkins Univ. Stud. Ceo/., 12: 69-80. Berry, E. W., 1937f. Late Tertiary plants from the territory of Acre, Brazil. Johns Hopkins Univ. Stud. Ceo/., 12: 81- 90. Berry, E. W., 1937g. Eogene plants from Rio Turbio in the territory of Santa Cruz, Patagonia. Johns

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Hopkins Univ. Stud. Geo/., 12:91 -98. Derry, E. W., 1937h. The Parinas Sandstone of Peru. Jofms Hopkins Univ. Swd. Geol., 12: 99-106. Derry, E. W., 1937i. b>wcr Cretaceous p lants beneath t he floodplain of the Orinoco from the state of Monagas, eastern Venezuela . Johns Hopkins Univ. Stud. Ceo/., 12 : 107- 110. Berry , E. W.,l937j. Succession of fossil floras in Patago nia . Proc. Nat/. A cat!. Sci. , 23: 537-542. Berry, E. W., 1937k. On the presence of the fern Wcithse/ia in Colombia, South America. J. Was/r. A cad. Sci., 27: 458-46 1. Berry, E. W., 19371. Cyrocarpus and o ther foss il plants from Cumarebo Field, in Venezuela. J. Wash. A cad. Sci., 27:501-506. Berry, E. W., 1938. Tertia ry flora from the Rio P ichilcufu , Argentina. Ceo/. Soc. Am., Spec. Pap., 12: 149 pp. Berry, E. W., 1939a. The fossil flora of Potosi, Bolivia. Johns Hopkins Univ. Stud. Geo/.,13: 9-68. Derry, E. W., 1939b. The fossi l p lants from Huallanca, Pcn1. Johns Hopkins Unil'. Srud. Ceo/., 13 : 73-94. Berry, E. W., 1939c. F ossil plants from the state of Anzoategui, Venezuela. Johns Hopkins Univ. Stud. Ceo/., 13: 137- 156. Berry, E. W., 1939d. Eocene plants from a well core in Venezuela. Johns Hopkin\· Un iv. Stud. Ceo/., 13: 157-162. Berry, E. W., 1940. A Cmparia from the Pliocene of trans-Andean Bolivia. J. Waslt. Acad. Sci., 30: 464-467. Berry, E. W., l942. Mesozoic and Cenozoic pla n ts o f South America, Central America and the Antilles. Proc. 8th. Am. Sci. Congr. Washington, D.C., 1940, 4: 365-373. Berry,E. W., l945a.Fossil floras from southern Ecuador. Johns Hopkins Univ.Sitld. Ceo/., 14: 93-150. Berry, E. W., 1945b. The Weichselia Stage in the Andean geosyncline. Johns Hopkins Univ. Stud. Ceo/., 14:15 1-170. Berry, E. W., 1945c. Late Tertiary fossi l plants from eastern Colombia. Johns Hopkins Univ. Stud. Ceo/.,14: 171-186. Berry, E. W., 1945d. T he genus Linguifolium of Arber. Johns Hopkins Unil'. Stud. Ceo/., 14: 187-190. Bertolio, A., 1860. Di un grasse fossi ledi Rio de J aneiro. Alii Soc. Ceo/. Resid. Milano, 5: 140-1 41. Beurlen, K. and Sommer, F. W., 1954. Restos vegetais fosseis e tectonica da Bacia Calcarea de Itaborae, estado do Rio de Janeiro. Bol. Div. Ceo/. Miner., 149: 1-27. Bigarclla, J. J . and Mousinho, M. R., 1966. Slope development in southeastern and southern Brazil. Z. Gemorplt., 10: 150-160. Bigarella, J. J., Mousinho, M. R. and Xavier da Silva, J., 1965. Processes anti Em•ironmetrls of tile Brazilian Quatemmy. lmpr. Univ. Parana (Curitiba), 71 pp. Bonazzi, A., 1962. Estudios palinologicos preliminares sabre el Arrccife del Alto Llan o de Calabozo, Venezuela. Acta Cimc. Venez., 13: 53-56. Bonetti, M. I. R., 1963. Florula Mesojurasica de Ia Zona de Taquetren (<;anadon del Zaino) Chubut. Rev. Mus. Argent. Cienc. Nat. Bemardina Rivadovia, Pa/eomol., I: 2~3. Bonetti, M. I. R., 1965. Nota preliminar sobrc una nueva flora Mesojurasica procedentede Taquetren (Chubul). Lilloana, 7: 17-21. Bonetti, M. I. R., 1966a. Protojuniperoxylon ischiguolastensis sp. nov. del Triasico de Ischigualasto (San Juan). Ameghiniana, 4: 211-216. Bonetti, M. I. R., 1966b: Consideracion es sobre algunos representantcs de Ia familia "Corystosperm · aceae··. Amegltiniana, 4: 389-395. Bonetti, M. I. R., 1968a . Las especies del gcnero Pseudoctenis en Ia flo ra T riasica de Barreal (San Juan). Amegltiniana, 5: 433-446. Bonetti, M. I. R., 1968b. Comunicacion sobre algunos representantes de Ia fami lia Corystospermaceae. J. Ceo/. Argent., ! : 249-250. Bo netti, M. I. R. and Herbst, R., 1964. Dos cspecics de Dictyophyllw n del Triasieo de P aso Flores, Provincia de Neuquen , Argentina. Amegiliniana, 3: 273-278. Bo nnet, E., 1905. Contribution a Ia flare Pliocene de Ia Province de Bahia (Bresil). Mus. flist. Nat. Bull., 11 :510-512. Bordas, A. F., 1937. Sobre Ia existencia de arboles en Ia Formacion Pampeana. Gaea, 5: 97-102. Borello, A. V., 1967. Sabre Cryptozoon sp., alga del Llanvirniano de Talacasto, San Juan. Amegltiniana, 5: 17-20.

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Frcnguc lli, J., 1936a. Diatomeas de Ia caliza de Ia cuenca de Calama en cl desierto de Atacama (Chile). Rev. Mus. Paleontol., Uni>•. Nad. La P/ara ( Argentina), I: 3-34. Fren gL>c lli, J., 1936b. El banco verde de Paso N iemann d el Rio Chico en el Chubut y sus dia tomeas. Re>•. Mus. Paleonlo!., Uni>•. Nac/. La Plata (Argentina ), I: 35-65. F renguelli, J., 1937. La flontla Jurasica de Paso Flores en el Neuquen con rcfcrcncias a Ia Pied ra l'intad~ y ostras floras Jurasicas Argentinas. Re>'. Mus. Pa/eontol., Univ. Nacl. La Plata ( Argentina), I: 67-108. Frcng uelli, J ., 1938a. Diatomcas del Quarandincnsc estuaria no d el R io Mata nza en Buenos Aires. Re>•. Mus. Paleontol., Univ. Nacl. La Plata ( Argentilra) , I : 291- 314. . Frenguelli, J., 1938b. Analisis micrascopico de l Tripoli de Arica , en Chile. Pub/. Dept. M in. Pet. Santiago de Chile, pp. 1- 7. Frenguclli, J., 1938c. Clathrirun reticu!are, probable representante fosil de un nuevo ti po de Silicoflagclados. Notas Mus. La Plata ( Paleonlol.), 3: 131-145. Frenguelli, J., 1940. Consideraciones sobre los silicoflagclados fosiles. Rev. Mus. La Plata ( Paleontol.), 2: 37-112. Frcnguelli, J., 194l a. Las Camptopterideas del Lias de Piedra Pintada en el Neuquen (Patagonia). Notas Mus . Paleontol., Unil•. Nac /. La Plata (Argentina), 6 : 25-57. F ren guell i, J., 194l b. Silicoflagelados y radiolarios del Tripoli del Valle Til- T il (Chile). Notas Mus. Paleontof. , Univ. Noel. La Plata (A rgentina), 6 : 93- 100. Frcnguclli, J., 194l c. Nuevas elementos floristicos del Magellania na de Patagonia austral. Notas Mus. Pakontol., Univ . Noel. La Plata (A rgentina), 6: 173- 202. Frenguelli, J., 1941d. Dicroidium ste/oneriamrm (Gein.) n. comb. Notas Mus. Paleontol. , Uni>•. Nac!. La Plata (Argentina), 6:393- 402. Frenguclli, J., 194 1e. Sagenopteris y Linguifo!ium del Lias de Piedra Pintada en el Neuquen (Patagonia). Notas Mus. Paleomol., Uni>•:Nac/. La Plata ( Argentina), 6:405-437. Frcnguelli, J., 194lf. Sobre Ia floru la Carbonifera del Agua de los Jejcnes, San Juan, conservada en el Musco de La Plata. No/(/s Mus. Paleoutol., Univ. Nac!. La Plata (Argentina) , 6:459-478. Frenguelli, J ., 194lg. Sobre Cycadocarpidium andium n. sp. del Retico de Cacheuta Mend oza. Notas Mus. Paleontol., Uuiv. Nac/. La Plata (Argentina), 6:485-498. Frenguelli, J ., 1941h. AI go mas sa bre Cycadocarpidium del Retico de Mendoza. Noras Mus. Paleomol., Univ. Nac. La Plata ( Argentina), 6; 537- 544. Frenguelli, J., J94li. Algunas diatomeas neuvas o raras del Su perpatagoniense del Chubut (Patagonia). Darwiniana 5: 224--227. Frcnguelli, J., 1942- 1946. Contribuciones a! con ocimicnto de Ia flora del Gondwana Superior en Ia Argentina, 1-33. Notas Mus. Paleon tol., Univ. Naci.La Plata (Argentina), 7-11. Frenguelli, J., 1943a. Proteaceas del Cenozo ico de Patagonia. Not as Mus. Pafeontol., Univ . Nac/. La Plata (Argentina), 8: 201-213. Frcnguelli, J ., ! 943b. Restos de Casuarina en el Miocene de El Mirador, Patagonia Central. Notas Mus. Paleonto/., Univ. Nac/. La Plata ( Argelllina), 8: 349-354. Frenguelli, J ., 1943c. Acerca de Ia presencia de Rhacopteris ova/a en el Paganzo I de Villa Union, La Rioja. Re>•. Mus. La Plata (Argentina), 2: 11- 47. Frenguelli, J., 1943d. Resena critica de los generos atribuidos a Ia "Serie de Thimrfe/dia". Rev. Mus. La Plata (Argentina), 2:225- 342. Frenguelli, J., 1944. Las especies del genera Zuberia en Ia Argentina. Ann. Mus. La Plata (Argentina), Sec. B (Pafeobot.), 1:1- 30. Freng uelli, J., 1945. Las Diatomeas del Platense. Rev. Mus. La Plata ( Argentina), 3: 77-221. Frenguelli, J., 1946. El Carbonifero Argentino segun sus floras fos iles. Rev. Asoc. Ceo/. A r·gent., 1: 107-115. Frenguelli, J., 1947. El genera Cladophlebis y sus representantes en la Argentina. Ann. Mus. La Plata (Argentina), Sec. B (Pa/eobot.), 2: 1- 74. Frenguelli, J., 1948. Estratigrafia y edad delllamado Retico en la Argentina. Caea (B. Aires), 8: 159309. Frenguelli, J., !949a. Los estratos con Estheria en el Chubut (Patagonia). Rev. Asoc. Ceo/. Argent., 4: 11- 24. Frenguelli, J., 1949b. Acerca de un nuevo descubrimiento de plantas en los estratos del Arroyo Totoral en Ia Sierra de los Llanos de -La Rioja . Rev. Asoc. Geol. Argent., 4: 153- 164.

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lignites, fresh or brackish wa ter shells, and leaf impressions, is n matter of considerable geologic interest. They were discovered first at Pcbas on the Rio Maranon many years ago a nd have freq uently been alluded to by a considerable number of authors who were passed in review by Gardner in 1927." (Berry, 1937f, p. 84).] . Gausscn, H., 1957. Biogeographic in lc XVJIIcme Congres lnternational de Geographic Rio d e J aneiro Aout, 1956. Ann. Geogr., 353: 14- 19. Geinitz, H. B., 1876. Ubcr Rhlttische Pflanzen und Thierreste in den Argentinischen Provinzen La Rioja, San Juan und Mendoza. Palaeoutographica Suppl., 3: 1- 14. Geomotz, H . B., 1925. Contribucioncs a Ia paleontologia de Ia Republica Argentina-Sobrc plantas· Y animales Reticos en las provincias Argentinas de Ia Rioja, San Juan, y Mendoza. Acad. Noel. Cieuc. Aetas, 8 : 333-347. (Translated by G. Bodenbender Anquin). Germeraad, J. H., Hopping, C. A. and Muller, J., 1968. Palynology of Tertiary sediments from tropical areas. Rev. Palaebot. Palyuol. , 6: 189- 348. Gerth, H., 1941. Die T ertilirfiorcn des slidlichcn Slidameri kas und d ie angcbliche Verlagcrung des Slidpols walm!nd dicser Pcriode. Geol. Rrmdsclr., 32:321-336. Gilkinet, A., 1909. Quelques plantcs fossiles des tcrrcs Magellaniques. Resultats Voyage du S. Y. Belgicaen 1897- 1899. Rap. Sci. Geoi.,AIII'ers, 5: 1- 6. ["Tertiary plants have been known from southern Chile (Coronel) since 1891, and a flora of apparently the same age is p resent at several localities in the extreme southern part of the continent (Gilkinet, 1909)." (Berry, 1917, p. 110).] Gonzalez G uzman, A. E., 1967. A Palynological Study 011the Upper LOl' Cuervos and Miratlor Formations. (Lower and Middle Eocene; Tibu Area, Colombia). Brill, Lei den, 68 pp. Gonzalez, E., Vander Hammen, T. and Flint, R . F., 1966. Late Quaternary glacial and vegetational sequence in Valle de Lagunillas, Sierra Nevada del Cocuy, Colombia. Leidse Geol. Meded., 32: 157- 182. Gordon, M., and Brown, R. W., 1952. Plantas Triassicas do sui do Brasil. Notas P1~1im., Bras. Div. Geol. Min., 54: 1-6. · Gordon, W. T., 1930. Note on Dadoxylon (Araucarioxylon) from the Bayoflsles, South G eorgia. In : Report on the geological collections made during the voyage o f the "Quest" on the Shackleton Rowett Expeditiorr to the South Atlantic and Weddel Sea in 1921-1922. Brit. Mus. (Not. Hist.) , Loud., pp. 24-27. Gothan, W., 1912. Dadoxylon. In C. Guillemain, Beitrlige zur Geologic Uruguays. Neues Jahrb. M iueral. Geol. Palaontol., 33: 234. Gothan, W., 1916. Die fossilen holzer von den Seymour und Snow Hill Insel. In: 0. Nordenskihold (Edito r), Wiss. Ergebn. Schwed. SUtlpol Exped. ( /901- /903) , 3 : 1-33. Gothan, W., 1925. Sobre restos de plantas fosiles procedentes de Ia Patagonia . Bot. Acad. Noel. Cieuc., Cordoba, 28: 197- 212. Cothan, W., 1927. Gondwanaptlanzen aus der Sierra de Los Llanos und benachbarten Gebieten.ln: B. v. Freybcrg (Editor), Geologische Untersuclumgen in der Sierra de Los Llanos (La Rioja, Argentinien) . Ablr. Senckeuberg Nat . Ges., 39: 341- 344. · Gothan, W ., 1928. Bemerkungen zur Alt-Carbonflora von Peru, besonders von Paracus. Neues Jahrb. Mineral., Geol., Paliioutol., 69 (Abt. B): 292- 299. · Gothan, W., 1950. Ober die merkwiirdigen fcigenartigen K ieselknollchen a us dem versteinerten Wald des Cerro Cuadrado in Patagonia. Misc. Acad. Berolinensis, I : 149- 154. Gothan, W. and Jongmans, J. W., 1951 . Beitrag zur Kenntnis von Alethopteris branueri White. An. Acad. Bras. Cienc., 23: 283-290. Gothan, W. and Jongmans, J .W., 1952. Contri bu~o para o conhecimento de Alethopteris bramreri White. Notas Prelim. Est. Div. Geol. Min. Agric., Rio de J., 55: 1-9. Groot, J . J. and Groot, C . R., 1964. Quaternary stratigraphy of sediments o f the Argentine Basin . A palynological Investigation. Trans. N.Y. A cad. Sci., 26:881-886. ["Calcareous fossils are so rare in these sed iments that they cannot serve as reliable stratigraphic ind icators, and the possibility that siliceous fossils could serve better seemed remote until recently. Hence we recommended to Prof. J. J. Groot that he undertake to extract and analyze the spores and pollen from these sediments. The resulting studies (Groot and Groot, 1964) of 5 Argentine basin cores (consisting mainly of lutite) defined an upper zone that is apparently post glacial in age and is overlying one that is ap parently Wisconsin o r last glacial. Beneath these

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there is an a lternation between these two types that may be interpreted to indicate glacial and interglacial stages. Groot and Groot in fer that there have been ·no appreciable clill'ercnces in Quaternary climat ic conditions in south ern South America. Ra ther it appears tha t the pollen zones arc related to sc<1 level changes, whic h greatly innucnccd the width of the coasta l plain cast of the A ndes'. T he actual occurrence of SltCh lowering has been demonstrated by sediment cores fro m t he shelf showing slight ly buried liltoral fauna over the entire area (Fray a nd Ewing, 1963; Richards and Craig, 1963). At the su ggestion o f Prof. Groot, L. H . Jlurckle made a survey of the diatoms in a number of samples, using criteria established by Jouse and o thers (1963) for glacial and interglacial zones. In general the zonatio n indica ted by the diato ms in eleven cores fully su bstan tiated that established by the spores and pollen." (Ewing, 1965, p. 20).1 G root, J . J . and G root, C. R., 1966. Pollen spectra from deep-sea sediments as indicators of climatic chan ges in southern South America. Ma,.. Geol., 4: 525-537. Groot, J . J . and G root, C. R., 1967. Pollen spectra from deep-sea sediments as indicators of climatic changes in southern South America. Abst1·. Rev. Palaebot. Palynol., 2: 14. Ha lle, T. G., 19 12a. O n the occurrence of Dictyozamiles in South.America. Pa/aeobot. Z., I : 40-42. Halle, T . G., I912b. On the geological structure and history of the Falkland Islands. Bull. Ceo/. Ins/. Univ . Uppsala, I I: 115-229. Halle, T . G., 1913a. T he Mesozoic flora of Graham Land. In : 0 . Nordcnskiold, (Editor), Wiss. El'gebn. Schwed. Sudpol Exped., 1901 - 1903 , 3: 1-123. Halle , T. G. , 191 3b. Some Mesozoic plant-bearing deposits in Patagonia and Tierra del Fuego and their fl oras. Kung/. Sven. 11et. Hand/. , 51 : 1- 58. Ha lle, T. G., 1913c. Om de Antarktisk a trakter nas Jurafl ora. C~ol. Foren. Forlwudl., Stockholm, 35: 605-606. Ha lle, T. G ., 1940. A fossi l fertile Lygodimn from the T ertiary of south Chile. Svens. Bot. Tidsk., 34: 257-264. Harrington, H. , 1934. Sobre Ia presencia de restos d e Ia flo ra de Clo.I'Sopteriscn las Sierras Australes de Buenos Aires y su significacion en to referente a las relaciones de Ia Serie Glacial Y Series Su pcriores. Rev. Mus. La Plata ( Argemina}, 34: 303-338. Hauthal, R., 1892. Nota sobre un nuevo genero de Filiceos de Ia formacion Rhetica del Challao (Prof. de Mendoza). Rev. Mus. La Plata (Argentina) , 4 :221- 223. Hautha l, R., 1898. Ober Patagonisches Tertar, etc. Z. Deut . Ceo/. Ces. , 50:436-440. [''Probably the first person to collect fossil plants in this general region, certainly the earliest that has come to my attention, was Rudolf Hauthal who spent 6 months in the region between Ultima Esperanza and Lago Argen tino in the fi rst half of 1898. In what he calls the uppermost Cretaceou s sandstone east of Lago Maravillo (Cerro Cazador, Cerro Guido) he collected Ostrea, Inoceramus, Acanthoceros, Baculites and many gastropods and dicotyledons like Salix, Acer, Quercus, etc." (Berry, 1937b, p. I 1).] Herbst, R., 1960 . Descripcion de ejmplares fertiles de Hansmamria (Protorlripis) papilio Fcru glio, procendentes de los estrados de Baquero (Santa Cruz). Act. Ceo/. Lilloana, 3: 227- 232. Herbst, R., 1961. Algu nos datos geologicos y estratigraficos de Ia zona Estancia Roca Blanca Y Alrededores, Provincia Santa Cruz. Ameghiuiaua, 2: 55-60. Herbst, R., J962a. Cleiclrenitesjuliensis n. sp. del J urasico medio de Santa Cruz, Patagonia. Ameglriniana, 2: 187- 190. Herbst, R., 1962b. Sobre las especies de Gleicheuites de los sedimentos Baqueroenses de Santa Cruz, Patagonia. Ameghiniana, 2: 141- 151. . Herbst, R., 1963. Chansitheca argentina n. sp. del Triasico superior de Santa Cruz. Patagonia. Ameglriniana, 3: 108- 112. Herbst, R ., 1964a. Addenda a Ia flora Liasica del Rio Atuel, Merrdoza. Rev. Asoc. Ceo/. Argent., 19: 204-206. Herbst, R ., 1964b. La flora Liasica de C. Meschio, Provincia de Chubut, Patagonia. Ameglriniana, 3: 227-234. Herbst, R ., 1964c. La flora L iassica de Ia zona del Rio Atvel, Mendoza A rgentina. Rev. Asoc. Ceo/. Argent. 19: 108-131. Herbst, R ., 1965a. La flora Fosil de Ia formacion Roca Blanca, Provincia Santa Cruz, P atagon ia. Lilloana, 12: 7-101. H erbst, R ., J965b. Algunos esporomorfos del T riasico de A rgentina. Ameghiniana, 4: 14 1- 152.

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Herbst, R., !966a. Revision de Ia floras Liascia de Piedra Pintada, Provi ncia de Neuquen, A rgentina. Reo•. Mus. UJ Plata ( Paleuntul.), 5: 27-53. Herbst, R., 1966b. Nuevos elementos de Ia llora fosil de Ia formacion Baquero, Santa Cruz, Patagonia. Lilloaua, 8 : 75- 86. · Herbst, R., 1966c. Nucvos elementos flo risticos de Ia formacion Piedra del Aguila, Neuquen, Argentina. Lil/oana, 8: 249-254. · Herbst, R., 1966d. La nora Liasica del G rupo Pampa de Agnia, Chubut, Patagonia. Ameghiniaua, 4: 337- 347. Herbst, R., 1968. Las no ras Liasicas Argent inas, con consideracio ncs cst ra tigraficas. Ill. J. Geo/. Argent., 1 : I45-162. He rbst, R ., 1970a. Estudio pal inologico de Ia Cuenca Ischigualasto-Villa Un ion (Triasico) Provincias ·San J uan- La Rioja. f. Introduction. JL Monoaperturado s. Ameglrinimra, 7:83-97. Herbst, R. , 1970b. Nota sobre Ia cstratigrafi a de Ia Provincia Corricntes, Argentina. Act. l v. J. Geol. TV Argent., 2. (Abstr.) Herbst, R. and Anzoatcqui, L. M., 1968. Nuevas plantas de Ia flora del J urasico med io (Matildense) de Taquct ren, Provincia de Chubut. Ameg!Jiniana, 5: 183-190. Hernandez, P. J., I967. l mportancia de Ia Palinologia. Mu.1. Nacl. Hist. Nat . (Chile}, 131: 1-3. Heusser, C. J., 1959. Review: Auer, V., The Pleistocene of Fuego-Patagonia. 2. The history o f the nora and vege tation. Ceogr. Rev., 49: 603-604. Heusser, C. J., 1960a. Postglacial environmental changes in the Laguna San Rafael A rea, southern Chile. Bull. Geol. Soc. Am., 7 1:2097- 2098. Heusser, C. J., I960b. Late-Pleistocene environments of the Laguna de San Ra-fael area, Chile. Geogr. Rev., 4: 555-577. Heusser, C . J., 1961. Some comparisons between climatic changes in northwestern North America and Patagonia . Auu. N. Y. Acad. Sci., 95: 642-657. Heusser, C. J., 1962. Some pollen profiles from the Laguna de San Rafael area,~Ch ile. /111. Con[. Palynology, lsi, Tucson, 1962; Abstr., Pollen Spores, 4: 350-351. Heusser, C. J., 1964. Some pollen profiles from t he Laguna de San Rafael area, Chile. In: L. M. Cranwell (Edito r), Ancient Pacific Floras. U niv. Hawaii Press, pp. 95- J 14. Heusser, C. J., 1965. Late Pleistocene p o llen diagrams from southern Chile . Cougr. Jut. Quaternary .Assoc. Bordder, /965; Abstr., p. 212. Heusser, C. J., 1966a. Polar hemispheric correlation: Pa lynological evidence from Chile and the Pacific northwest of America. R. Melero/. Soc., Proc. Int. Symp. Wor·ld Climate, pp. 124-141. Heusser, C. J ., 1966b. Late-Pleistocene pollen diagrams from the Province of Llanquihue, southern Chile. Proc. Am. Philos. Soc., 110: 269- 305. Heusser, C. J., 1969. Vegetation history in South America. Abstl'. Symposium, Quatemary

Vegetation History, XI Jut. Bot. Congr. Seattle, 1969.

Hicken, C. M ., I 917. Relacion de Ia flora Cretacea con le actual. Rev. Centr. Est. Ing., 18: 42-44. ' Hicken , C. M., 1927. Contribucion at conocimiento de Ia bibliografia botJ!nica Argentina. Danviniana, l : 191-318. H icken, C. M., 1928. La flora de Ia Periode Cretacee et ses relations avec Ia flore actuelle. Resume, Ann. Soc. Cienc. Argent., I05: 272- 277. H icken, C. M., 1929. Segunda contribucion-al co nocimiento de Ia bibliografia Argentina. Darwiniana, 1 : 319-430 . Hicken, C. M., 1930. Tercera contribucion al conocimiento de Ia bibliografia A rgentina. Daroviniana, l : 431 -539. Hollick, A., and Berry, E. W., 1924. A late T ertiary flora from Bahia, Brazil. Johns Hopkins Univ. Stud. Ceo/., 5: 11- 137. Horn af Ran tzien, H., 1950. Charophyta reported from Latin America. Kong. Sven. Vet. Akad. Arkiv Bot., I : 355-411. Horn af Ra ntzien, H., 1951. On the foss il Charophyta of Lat in America. Sven. Bot. Tidsk., 45: 658677. Howe, M . A., 1922. Two new Lithothanm ieae, calcareous algae from the lower Miocene of Tr in idad, British West Indies. Proc. U.S. Nat/. Mus. , 62: 1- 3. H uertas, G. C. and van der Hammen , T., 1953. Un possible banano (Musa) fossil del Cretaco de Colombia. Rev. Acad. Colombiana Cienc., 9 : 11 5-116.

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Hunickcn, M., 1955. Depositos Ncocretacicos y Tcrciarios del extrcmo SSW de Santa Cruz. Mus. Argent. Cicuc. Nar. Oemardino Rivadavia, Cicuc. Ceo!., 4: 1- 164. (Summarizes pa leobotany oft he Santa Cruz, Argentina, region). Hunicken, M., 1966. Flora Tcrciaria de los cstratos de Rio Turbio, Santa Cruz (nivclcs plantifcros del Arroyo Santa Flavia). Rev. Fac. Cienc. Exp. Fis., Ser. Cienc. Nor., 27: 139-260. Hunicken, M.A., 1968. Sobrc los tipos de Carolitesparagonica Spcgazzini y Amegldnoire.1· desiderata Spegazzini. Ameghinimw, 5: 447-450. Irigoycn, M. R. and Stover, L. E., 1969. La palinologia como elemento decorrclacion del Triasico en Ia cuenca Cuyana. J. Geo/. Argent., 2: 425-447. · Jain, R. K., 1968. MiddicTriassicpollcngrainsandsporesfrom MinasdcPetroleo beds of the Cacheuta Formation (Upper Gondwana), Argentina. Palaeonrographica B, 122: 1-47. Jain, R. K. and Delcvoryas, T., 1967. A middle Triassic flora from the Cacheuta Formation, Minas de Pctrolco, Argentina. Palaeontology, 10:564-589. Japiassu, A.M. S., 1970. Madeira fossil-Huniriaceae de Irituia, Estado do Para. Bot. Mus. Paraense E. Cooldi (Ceo!.), 14: 1- 12. Jenks, W. F., 1951. Triassic to Tertiary stratigraphy ncar Cerro de Pasco, Peru. Bull. Geo/. Soc. Am., 62: 203-220. ["Recently, some Upper Cretaceous or Lower Tertiary charophyte remains from Peru according to determinations by Peck were tentatively referred to Ac(lis)tochara mile/fa Peck and Reker (Jenks, 1951, p. 2 14)." (Horn af Rantzien,1951).] Johnson, J. H., 1955. Early T ertiary coralline algae from Trinidad, British West Indies. Eclogae Geo/. He/v.,48: 69-78. Jongmans, W. J., 1954. The Carboniferous flora of Peru. Bull. Brit. Mus. Nat. His/., 2: 191 - 223. Jongmans, W. J. and Gothan, W., 1951. Beitrage zur Kenntnis von Alethopteris brmmeri White. An. Acad. Bras. Cienc., 23: 283-290. Jordao, E., 1878. Noticia sobre una planta fossil encontrada no Rio do Peixe. Re1•. /nst. Polyteclt. Sao Paulo, 2: 54-55. · Just, T., 1952. Fossil floras of the southern hemisphere and their phytogeographical significance. Dull. Am. Mus. Nat. Hist., 99: 189- 203. Karsten, H., 1850. Beitrag zur Kenntnis der Gesteinedcs nordlichen Venezuela. z. Deut. Ceo/. Ces.,2: 345-361. (Sec annotation for Schlagintweit, 1919 reference). Katz, H. R., 1961. Descubrimiento de una microflora Neocomiana en Ia Formacion Aqua Fresca (Eocena) de Magellanes y su significado con respecto a Ia evolucion tectonica de Ia zona. Univ. Clti/e, Ann. Fac. Cienc. Fis. Math., lnst. Geolr{Santiago), 21: 132-141. Kedves, M. a nd Sole de Porta, N., 1963. Comparacion de las esporas del gencro Cicatricosisporiles R. Pot. y Gcll. 1933 de Hungaria y Colombia. Algunas problemas referente a su significado estratigrafico. Uuiv.lnd. Santander, Pub!. Cienc.,Bol. Ceo/., 12:51-76. Knowlton, F. H ., 1913. Review: The Mesozoic flora of Graham Land, by T. G. Halle. Science, 37: 763-764. Knowlton, F. H., 1918. Relations between the Mesozoic floras of North and South America. Bull. Geo!. Soc. Am., 29:607- 614. Koch, E. und Blissenach, E., 1960. Die gefalteten Oberkretazisch- Tertiaren Rotschichten im MitleiUcayali Gebiet, Ostperu. Geol. Jaltrb., 43: 1- 103. (Mentions some Charophytes from Peru). Krasser, F., 1903. Konstantin von Ettingshausen's Studien tiber diefossile Flora von Ouricanga in Brasilien. Kon. Akad. Wiss. Wien, Math-Nat. Kl., 11 2: 852- 860. Krause!, R., 1925. Beitriige zur Kenntnis der fossilen Flora Siidamerikas. I. Fossile H olzer a us Patagonien und benachbarten Gebieten. Ark. Bot., 19: 1- 36. Krause!, R.,1949. Diefossilen Koniferen-Holzer (unter Ausschluss von Araucarioxylon Krause!). II. Kritische Untersuchungen zur Diagnostik lebender und fossiler Koniferen -Holzer. Palaeontograpltica B., 89: 83-203. Krause!, R., 1954. Spongiopltyton nov. gen. (fhallophyta) und Haplostigma Seward (Pteridophyta) im Unter-Devon von Parana. In : Paleontologia do Parana, Comemorativo 1st Centenario Estado do Parana. Publicado pe/a Comissao de Comemoracoes do Centario do ParQJla, Distribuido pelo Museo Paranaense, Curitiba, pp. 194-210. Krause], R., 1960. Spongiopltyton nov. gen. (fhallophyta) e Haplostigma Seward (Pteridophyta) do Devoniano Inferior do Parana. Braz. Dep. Nacl. Prod. Min., Div. Geo/. Min., 15: 1-41.

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Krause!, R., !961. Lycopodiopj·is derbyi Renault und einigc andere Lycopodialcs a us den GondwanaSchichtcn. Palaeontograplrica B., 109: 62-92. Krausel, R. and Dolianiti , E., 1957. Restos vcgctais ctns camadas Picos, Devoniano Inferior do Piaui. Braz. Dep. Nac!. Prod. Min., Di1•. Geo/. Miu. , 173: 1- 19. Krause!, R. and Dolianiti, E., 1958. Gymnospermholzer a us dcm Palaezoikum Brasiliens. Palaeomographica B.,I04: 115-137. Kurtz, F., 1894. Contribucioncs a Ia palaeophytologia Argentina, I-11. Rev. Mus ..Lo Plata ( A rgentina), 6: 119- 139. Kurtz, F., 1895. Sobrc Ia existe ncia del Gondwana I nferior en Ia Republica Argentina (plantas fosilcs del Bajo de Velis, Prov. de San Luis). Re1•. Mus. La Plata ( Argentina), 6: 125-139. Kurtz, F., 1896. Recent discoveries of fossi l plants in Argentina. Geol. Mag. Lorul., 3:446-449. Kurtz, F., 1899. Sobre Ia existencia de una Dakota-Flora en Ia Patagonia austrooccidenta l. Re1•. Mus. La Plata ( Atgentina), 10: 45-95. Kurtz, F., 1900. Essai d' unc bibliographic botanique de !'Argentine. Bol. Acad. Nac/. Cienc. Cordoba, 16: 1-91. Kurtz, F., 1902a. Contribucioncs a Ia palaeophytologia Argentina . 7. Sur !'existence d'unc flore Rajmahalicnne dans le Government du Neuquen. Rev. Mus., La P/ara (Argerrtina), 10: 235-242. Kurtz, F., 1902b. Contribuciones a Ia palaeophytologia Argentina, III, Sobre Ia existencia de una Dakota fl ora en Ia Patagonia austro-occidental (Cerre-Guido, Gobernacional de Santa Cruz). Re1•. Mas. La Plara ( Argelllina), 10: 45-60 Kurtz, F., 1910. Planilla 4. Fosilcs Reticos. En: Stappcnbcck, R., La Precordillera de San Juan y Mendoza. Amt. Min. Agric., Geo/. Min.,4: 187. Kurtz, F., 1921. Atlas de pla ntas fosilcs de Ia Republica Argentina. Aetas Acad. Nacl. Cienc. C01·doba, 7: 129-153. Kuyl, 0 . S., Muller, J. and Waterbolk, H. T., 1955. The application of palynology to oil geology with reference to western Venezuela. Geol. Mijnbouw, 17: 49-76. Langenheim, J. H., 1961. Late Paleozoic and Early Mesozoic plant fossils from the Cordillera Oriental of Colombia and correiation of the G iron Formation. Serv. Geo/. Nac!. Bot. Geol. ( Colombia), 8:95-132. Leanza, A. F., 1948. Los bosqucs petrificados de Santa Cruz. Au. Soc. Cienc. Argent., 146: 174--188. Leidelmeyer, P., 1966. The Paleocene and lower Eocene pollen flora of Guyana. Leidse Geol. Meded., 38:49-70. Lisson, C. I., 191 7. Edad de los Fo~"i/es Peruanas y Dim·ibuciou de sus Depositos entoda Ia Republica. Lithografia y Tit. C. Fabbri, Lima, 2nd ed., 147. pp. (3rd ed., 1924. Imprenta Americana, Lima. Sec also Appendix, 1926. Bot. Soc. Geol. Pem, Lima: 41-46.) ("Finally in 1917 in Lisson's admirable compilation of Peruvian fossi ls the two species L epido· deudron t·imosum and L, obovat11m are listed, the determina tions being by the late Professor Zeil· Jer, and the age is given as Westphalian." (Berry, 1922c, p. 11).] Loomis, F. B., 191 3. A fossil forest. In : Hunting extinct animals in the Patagonia Pampas. Dodd, Mead, New York, pp. 71-77. Lorenzo, J. , 1958. Prehistoire et Quaternaire recent au Mexique: etat actue1 des connaisances. Antropologie, 62: 62-83. Loureiro Fernandes, E. C. and Guimaraes, 0., 1964. Notas palinologicas V. Analise polinica do Sambaqui do Porto (Brasil). Bot. Univ. Parana, Bot., 12: 3- 7. Lundblad, B., 1955. Contributions to the geological history of the Hepaticae. II. On a fossil member of the Marehantineae from the Mesozoic pla nt-bearing deposits near Lago San Martin, Patagonia (Lower Cretaceous). Bot. Notiser, 108:22-39. Lundquist, G., 1919. Fossile Pflanzen der Glossopteris flora a us Brasiliens. Kung/. Sven. Vet. Akad. Hand/., 60: 1-36. Maack, R., 1929. Lycopodiopsis derbyi aus dem Kustengebiet von Santa Catharina. Centra/b. Min. Ceo/. Palaeontol. Jaltrb., Abt. B, 10: 508-512. Maack, R., 1947. Lycopodiopsis derbyi Renault, documento de idade Palaeozoica das camadas Terezina do Brazil meridonal. Arq. Bioi. Tee/mol., 2: }58-208. Machado, 0., 1946. Fruto fossilazado do Itabirito. Rodriquesia, 10:47. Machado Brito, 1. , 1965. Novos microfosseis Devonianos do Maranhao. Univ. Boltia Esc. Geo/. Pub/. Av11lsa, 2: l -4.

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A. GRAHAM

Vander Hammen, T ., ~1%2. Palinologia de Ia region de .. Laguna de los Bobos", historia de su clima. vegetacion y agricultura durante los ultimos 5,000 a nos. Rev. Acad. Colomb..Cieuc., 1.1: 359-~61. van dcr Hammen, T., 1963a. A palynological study o n the Quaternary of Bnttsh Gmana. Leulse Geol. Meded., 29 : 125- 180. v an der Hammen, T., 1963b. Historia de clinm y vegetation del Plcistoceno superio r y del Holoceno de Ia Sabana de Bogota. Bal. Geol. ( Bog01a}, 11 : 189- 260. Van der Hammen, T., 1963c. Problems of Quaternary botany in the tropics (with special reference to South America). Ber. Geobot. lnst. Riibel ( Ziiriclr), 34: 62. Van der Hammen, T., 1964a. A pollen diagram from the Quaternary of the Sabana de Bogota (Colombia) and its significance for the geology of the northern Andes. Geol. Mijnbouw, 43: 3. .· Van dcr Hammen, T., 1964b. T he Quaternary h istory of the vegetation in northern South Amcnca. lOth Int. Bot. Congr. ( Edinburgh), Abstr., p p. 270-27 1. . Van der Hammen, T., 1965. Palynological da ta on the h isto ry of savannas in northern South Amenca. Congr.lnt. Quaternary Assoc., 7th , Boulder, Colorado, Abstr., p. 480. Vander Hammen, T., 1966a. Etudes (Jalynologiques dans Ia partie nord de Ia Guyanc. Tijdschr. Korr. Ned. Aardr. Genoot., 83: 128-138. Van der Hammen, T., 1966b. De palynologic van het Guiana-bekken. Tijdsclrr. Ko11. Ned. Aanlr. Genoot., 83 : 128- 138. Vander Hammen, T., 1967. Palynologia Neotropica. Brill, Leidcn, 27 pp. Van der Hammen, T., 1968. Climatic and vegetational successio n in the Equatorial Andes of Col~m bia. In: C. T roll (Editor), Ceo-Ecology of the Mormtainous Regions.JJf the Tropical Amerrcas. Dummlcrs Verlag, Bo nn, pp. 187- 194. . Vander Hammen. T ., 1969. Introduction and short outline of the history o f the"youngcr"areas of the Guianes. Kou. Ned. Geol. Mij11bouwk. Genoot., 27 : 9-12. Van dcr Hammen, T. and Burger, D., 1966a. Pollen fl ora and age of the Takutu Formation (Guyana). Leidse Geol. M eded., 38 : 173- 180. . Van dcr Hammen, T. and Burger, D.,- 1966b. Palynology and age of the Takutu Formatton(Guyana). 7th Int . Guia11a Geol. Conf, 22 : 10 pp. . Van der Hammen, T. and Garcia de Mutis, C., 1964. La flora del polen del Paleocene de Colomb ta. Bal. Geo/. ( Bogota), 12:33-45. . . Vander Hammen, T. and Garcia de Mutis, C., 1966. The Paleocene pollen flora of Colombta. Letdse Geol. Meded., 35: 105- t1 6. . . Van der Hammen, T. and Gonzalez, E., 1960a. Holocene a nd Late Glacial cit mate a nd vegetatton of Paramo de Palacio ( Eastern Cordillera, Colombia, South America). Ceo/. Mijnbouw, 12: 737~ . Van der Hammen, T. and Gonzalez, E., t 960b. Upper Pleistocene and Holocene cltmate an d vegetation of the "Sabana de Bogota" (Colornbia, South America). Leitlse Ceo/. Mede~., 25 : 261-3 15.. Vander Hammen, T. and Gonzalez, E., 1963. H istoria de clima y vegetation del Pletstoceno Supenor y del Holoceno de Ia Sabana de Bogota . Bol. Ceo/. (Bogota), II : 189-260. Vander Hammen, T . and Gonzalez, E., 1964. A pollen d iagram from the Quaternary of the Sa~ana de Bogota (Colombia) and its significance for the Geology of the northern Andes. Geol. Mynbouw, 4 3: 113- 117. Van der H ammen, T. and Gonzalez, E., 196Sa. A pollen diagram from Laguna de Ia Herrera (Sabana de Bogota). Leidse Geol. Meded., 32: 183- 191. Vander Hammen, T. and G onzalez, E., 1965b . A Late-Glacial and Holocene pollen diagram from Cienaga del Visitador (Dept. Boyaca, Colombia). Leidse Ceo!. Meded., 32: 193-2? 1. van der Hammen, T . and Head, T., 1957. Po llen a nalysis of Pleistocene lake-sedtments from t~e Sabana de Bogota (Colombia, South A merica). 5th Congr. 1111. Quatemary Assoc. ( MadndBarce/oua} Abstr., p. 75. ·. Vander Hammen, T . and Nelson, H. W., 1955. T he caves of Cunday (Colo mbia, South Amen ca). Leidse Geol. Meded., 20: 89-99. . . Vander Hammen, T . and Parada, A., 1958. Investigacion de algunos importantes yactmrentos de diatomita,caolinyareillasd elaSabanadeBogota. Univ. lnd. Santander Bal. .c e?l., 2: 5-25. Van der Hammen, T. and Vogel, J. C., 1966. TheSusaca-Interstadial and the subdtvtston of the LateGlacial. Geol. Mijnbouw, 45: 33- 35. . Van d er Hammen, T . and Wymstra, T . A., 1964. A palynological study on the Terltary and upper.

LITERATURE ON VEGETATIO NA L HISTORY IN LATIN AM ERICA

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Cretaceous of British Guiana . Leidse Geol. Meded., 30: 183- 24 1. Van dcr Hammen, T ., Wymstra, T . A. and Lcidelmeyer, P., 1961. Paleocene sediments in British Guiana and Surinam. Geol. Mijllbamv,40: 231 . Van Gijzel, P., Van dcr Hammen, T . and Wymstra, T . A., 1967a. Correlation of Pleistocene deposits in The Netherlands, Germany, Spain, and Sou th America. Rev. Paleobot. Palynol., 2: 13. Van Gijzel, P., Van dcr Hammen, T. :md Wymstra, T . A., 1967b. Long-distance correla tion of Pleistocene deposits in South America, Spain, and T he Netherlands. Palaeogeogt·., Palaeoc/imatol., Pa/aeoecol., 3: 65-72. Volkheimer, W., 1968. Esporas y granos de polcn d el Jurasico de Neuquen (Republica Argentipa). I. Dcscrip<;ioncs sistcmaticas. Ameghi11iaua, 5: 333-370. . Volkheimer, W., 1969. Esporas y granos de polcn del Jurasico de Neuquen (Republica Argentina). 2. Asociaciones m icrofloristicas, aspectos paleoecologicos y pa lcoclima. Ameghi11iano, 6: 127- 145. Von Post, L., 1929. DieZcichensch rift der Pollc.nstastik. Geol. Foren. Stockholm Forh., 51: 543- 565. Von Post, L., 1931. Eldslandets Postglacial k limah istoria. Geol. Foren. Stockholm Forh., 53: 373-374. Von Post, L., 1946. The prospect for pollen analysis in the study of the earth's climatic history. New Plrytologist, 45: 193- 217. Vuilleumier, B., 1971. Pleistocene changes in the fauna and flora of South America. Science, 173 : 771- 780. Wall, G. P. and Sawkins, J. G., 1860. Report on the geology of Trinidad. Tri11idad Geol. Sarv. Mem., 178 pp. [" T he presence of fossil plants in the Tertia ry of the is land of Trinida d was fi rst men tioned in Wall and Sawkins historic ·report on the geology of that colo ny. Leaf impressio ns, lignite and silicified wood arc described at some length by Hermann Cruger in an append ix to the geological account, but in a very indefinite way and without a ttempting o ther than tentative identifications." (Berry, 1925f).] Wetzel, W., 1962. Ein verstcincrter (Verkieselter) Wflld im Chilenischen Tertiar. Geol. Rrmdsch., 52 : 861-869. Wh ite, D ., 1905. Flora oft he Brazilian Coal Measures. Science, 21: 700. White, D., 1907. Permo-Carboniferous climatic changes in South America. J. Geol., 15: 615-633. White, D., 1908. Fossil flora of the Coal Measu res of Brazil. Brazil Miuist . Agric., Dept. Nacl. Prod. Min., Comm. Estud. Minas Carvao dePedro do Brazil, 3:339-6 17. White, D., 1913. A new fossil plant from the state of Bahia, Brazil. Am. J. Sci., 35: 633-636. Wiela nd, G. R., 1926. Certain R hactic seeds fro'm the M inas de Petrolco, Argentina. Bull. Geol. Soc. Am., 37:242. Wieland, G. R. , 1935. The Cerro C uadrado petrified forest . Carnegie Just. Wash . Pub/., 449 : 1- 180. (Middle J urassic of Argentina). Wymstra, T. A., 1967. A pollen diagram from1he upper Holocene o f the lower Magdalena Valley, Leidse Geol. Meded., 39:261-267. Wymstra, T. A., 1968. The identity of Psi/atricolporites and Pelliciero. Acta Bot. Neerl., 17: 114-1 16. Wymstra, T. A., 197 1. T he palynology of the Guiana coastal Basin. De Kempenaer, Oegstgcest, The Netherlands, 62 pp. Wymstra, T. A. and Van der Hammen, T., 1964. Palynological data on the age of the bauxite in British Guiana and Surinam. Geol. Mijnbo11w, 43: 143. Wymstra, T. A. and Vander Hammen, T., 1966. Palynological data on the history of tropical savannas in northern South America. Leidse Geol. Meded., 38: 71-90. Wolf,T. and Von Rath, G., 1876. (Unter "Brief!. Mitt.", without title). Z. Deut. Geol. Ges., 28. ["Teodo ro Wolf... , long a resident of Ecuador published as early as 1876 an account of his travels in southern Ecuador accompanied by a map, and in this paper mentio ns the occurrence of fossil plants. He also in 1879 gave an account of the geology of the Cuenca basin in his Relacion de un Viaje geognostico por las Provincia del Azuay, and named the Azogues sandstone, b ut was uncertain as to its age except t hat it was p re-Quaternary and much later than the schists which u nderlie it. He was inclined to thin k its age to be Mesozoic, being influenced by the generalization of von Buch, Humboldt, Geninitz, and o thers that all the sedimentaries in the Andes from Mexico to Peru were of Cretaceous age." (Berry, l945a, p. 94).] Ybert, J.P. and Marques, M ., l970. Polarisaccites nov. gen. Pollen Spores, 12: 469-481.

358

A. GRAHAM

Yoshida, R., 1966. Nota sabre urn !lifo de G lossoptcridac na Carnada lrapua, Crisciuma, S.C. Bol. Soc. Bras. Geol. (Sao Paulo), 15: 69-77. Zeillcr, R ., 1874-1875. Note sur lcs plantcs fossile s de La Tcrncra (Chile). Bull. Soc. Geo/. Fr., 3: 572574. Zcillcr, R., 1895a. Note sur Ia fiorc fossilc des gisements houillers de Rio Grande do Sui. Bull. Soc. Geol. Fr., 23: 601 - 629. Zeillcr, R., 1895b. Sur quelques cmprcintcs vcgctalcs des gisements houillers du Bresil meridio nal. Compt. Rend. Acad.Sci.Paris, 121:961-963. · Zciller, R., 1896. Rcmarques sur Ia fiorc fossile de !'Altai a propos des derniercs decouvertes palcobotaniqucs de MM. les D rs. Bodenbendcr et Ku rtz dans Ia Rcpublique Argentine. Bull. Soc. Gcol. Fr., 24: 466-487. Zeillcr, R., 1898. S ur un Lepidodendron silicific du Bresil. Co mpt. Rend. Acad. Sci. Paris, 127: 245-247. Zcillcr, R ., 1914. Sur quelques plantcs Wcaldicnncs rccucillics au Perou par M. La Capitaine Bertham. Rev. Gen. Bor., 25:647- 672. Zigno, A. de, 1863. Sopra i depositi di pi ante fossili dell' America scttentionale, delle Indie e dell' A ustraJia che alcuni autori riferirono aii'Epoca Oolitica. A ccad. Potavina Sci., Lell. Arti, Rev. Periodica dei Lavori, 12: 139-152. Zingano, A. G. a nd Causuro, A. D., 1959. Aflorarnientos fossiliferos de Rio Grande do Su i. Bol. lnst. Cienc. Nat. , 8: 1-48.

Selected references on the pollen morphology of predominately neotropical taxa Barros, M. M ., 1963. Cont ribu~ao ao cstudo das poliades polinicas em Leguminosae-Mimosoidcae. AtasSoc. Bioi. Rio de!., 1: 1-6. Barros, M. M., 1966. Contribu i~ao aoestudo palinologico das Leguminosae dos arredorcs de Fortaleza, Ceara; J. Subfamilia Mimosoideae. Re1•. Bras. Bioi., 26 :385-399. Ba rth, 0. M., 1962a. Catalogo sistematico dos polens das plantas arboreas do Brasil meridional (Partecomple mentar : Coniferales). Mem.lmt. Oswaldo Cwz, 60: 199-208. Barth, 0 . M., 1962b. Catalogo sistematico dos polens das plantas arboreas do Brasil meridio na l. 2. Monimiaceae e Dilleniaccae. Mem. lust. Os ~raldo Cruz, 60: 405-420. Barth, 0. M., 1963. Cata!Dgo sistematico dos polens das plantas arboreas do Brasil meridional. 3. Theaceae, M arcgraviaceae, Ochnaceae, G uttiferae e Quiinaceae. Mem. l ust. Oswaldo Cmz, 61: 89-l!O. Barth, 0 . M., 1964a. Catalogo sistematico dos polens das plantas arboreas do Brasil meridio na l. 5. Leguminosae: Papilionatae. M em. lnst. Oswaldo Cruz, 62:95-1 23. Ba rth, 0 . M ., 1964b. Catalogo sistematico dos polens das plantas arboreas do Brasil meridional. 6. Leg uminosae: Caesalpinioideae. Mem. lust. Oswaldo Cmz, 62: 169-192. Barth, 0 . M., 1965a. Glossario palinologico. Mem. lust. Oswaldo Cruz, 63: 133-162. Barth, 0 . M., 1965b. Feinstruktur des sporoderms einiger Brasilianischer Mimosoiden-Po1yaden. Pollen Spores, 7: 429-442. Barth, 0. M., 1966. Estudos morfo logicos dos polens em Caryocaraceae. Rodriquesia, 25: 351-428. Barth, 0 . M., 1969. Analise 'microscopica de algumas amostras de mel. 3. Polen isolado. An. Acad. Bras. Cienc., 42:747- 772. Barth, 0. M., J970a. Analise microscopica de algumas amostras de mel. I. Polen dominante. An. Acad. Bras. Cienc., 42: 351- 366. Bartb, 0. M., 1970b. Analise microscopica de algumas amostras de mel. 2. Polen acessorio. An. A cad. Bras. Cienc., 42: 571- 590. Barth, 0 . M., 1971. Catalogo sistematico dos polens das plantas arboreas do Brasil meridional. 9. Complemento a parte 7: Cupilea (Lythraceae). Mem. lnst. Oswaldo Cruz, 69: 93- 101. Barth, 0. M. and Silva, S. A. F., 1963. Cata logo sistematico dos polens das plantas arboreas do Brasil meridional. 4. Cunoniaceae, Rosaceae e Connaraceae. Mem. Jnst. Oswaldo Cruz, 61:411428. Barth, 0. M. and Silva, S. A. F ., 1965. Catalogo sistematico dos polens das plantas arboreas do Brasil meridional, 7. Thymelaeaceae, Lythraceae, Lecythidaceae, Rhizophoraceae, Combretaceae. Mem. lnst. Oswaldo Cruz, 63: 255-273.

LITERATURE ON VEG ETATIONAL HISTORY IN LATIN AMERICA

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Barth, 0. M. and Yoncshigue, Y., 1966. Cat alogo sistematico dos polcns das plantas arboreas do Brasil meridional. 8. Leguminosae (Mimosoidcac). Mem.lnst. Osll'aldo Cruz, 64: 79- 111. Batalla, A., 1942. Estudio morfologico de los granos de polcn de las plantas vulgares del Valle de Mexico. Ann. lmt. Mex ., 11: 129- 161. Borbolla Camacho, G., 1947. Estud;·os de los Polenes y Hongos de/a AtmoJfera de Ia Ciudadde M exico. Tcsis, Escucla Nacl. Cienc. Bioi., 1nst. Po litcc. Nacl. (Mcx ., D .F.), 73 pp. Braga, R., 1961. Flora Apicola de Curitiba.l. (Pa rana-Brasil). Bol. Univ. Parana, 2: 1- 11. Cabrera, P. U., 1966. Flora Apicola en e/ Mwticipio de Villa de Arriaga, S.L. P. Tcsis, Escue1a Nacl. Cienc. Bioi., l ost. Po litcc. Nacl. (Mexico, D.F.), 50 pp. Campos, S. M. and Salgado labouriau, M. L., 1962. Pollen grains ofplantsofthe Cerrado. 3. Grasses. An. Acad. Bras. Cienc., ;14: 101-110. Coz Campos, D., 1964. Etude des grains de polcn des Lythracees du Perou. Pollen Spore.!, 6: 303- 348 . Gonzalez Cerezo, H ., 1964. Claves Grajicas p ara Ia ldentificaciou de las Fami/ias mas Comunes de Plantas Vasculares M exicanm·, segun los Caracteres de Esporas y Gmuos de Polett. Tesis, Univ. Nacl. Auton. Mex. (Mexico, D.F.), 96 pp. · Gonzalez Quintero, L., 1967. Flora Poliuica y Tipos de Vegetacion del Valle tiel Mezquital. Tesis, Escuela Nacl. Cienc. Bio i., l nst. Politec. N ac. (Mexico, D. F.), 135 pp. G onzalez Quintero, L., 1969. Morfologia po linica: Ia flora del Valle del Mezquital, Hidalgo. Paleoeco/., 3: 1- 185. Graham, A. a nd G ra ham, S. A., 1967a. Estudios de polcn de especies de Cuphea de Mexico: R esumeue, Tercer Congr. Mex. Bot. ( M exico, D. F.), pp. 14-15. Graham, A. a nd Graham, S. A., 1967b. Pollen morphology and systematics of Cup/tea (Lyt hraceae). Abstr., Am. J. Bot., 54: 658. Graham, A. and Graham, S. A., 1967c. Pollen morphology and taxonomy of Cup/tea (Lythraceae). Rev. Pa/aeobot. Pa/)•1101., 3: 155-162. Graham, A., Graham, S. A. and Geer, D. A ., 1968 . Palyno logy and systematics of Cup/tea (Lythraccae). 1. Morphology and ultra-structure o f the pollen wall. Am. J. Bot., 55: 1080-1088. G raham, A. and Graham, S. A., 1971. Palynology and Systematics of Cuphea (Lythraceac). 2. Pollen morphology and infragenericclassification. Am. J. Bot., 58:844- 857. Guinet, Ph., 1969. Lcs Mimosacees etude de palynologie fondamentalc, correlations, evolution. lnst. Fr. Pondicltery Trav., Sect. Sci. Tech., 9: 1- 293. Handro, W., 1965. Pollen grains of plants of the Cerrado. X. Ama ranthaceae. Au. A cad. Bras. Cienc., 37 (3/4): 557-565. Hernandez, P. J., 1966. N otas palinologicas de l norte Argentino, Provincia Altoand ina. I. Compositae. Ameghiniaua, 4: 305-3 10. Heusser, C., 1971. Pollen and Spores of Chile_U niv. Arizona Press, Tucson, Ariz:, 167 pp. Marques, M. and Melhem, T. S., 1966. Pollen grains of plants of the Cerrado. 11. Apocynaceae. An. Acad. Bras. Cienc., 38:371- 378. · Marticorena, C., 1961. Morfologia de los gran os de polen de las Polemoniaceae Chi1enas. Gayana, 2:5-12. Ma rticorena, C., 1962a. Morfologia de los granos de polen de Euphorbiaceae Chilenas. Gayana, 5: 1-12. Marticorena, C., 1962b. Morfologia de los granos de polen de las Ma lpighiaceae Chilcnas. Gayana, 5: 13- 17. M articorena, C., 1962c. Aberraciones morfologicas en granos de polen de Tropaeolum trico/or Sweet. Gayana, 5: 18-21. M articorena, C., 1968. Granos de polen de plan tas Chilenas. I. Gayana, 17 : 1-66. M atos, M. E. R. and Melhem, T. S., 1966. Pollen g rains of plants of the Cerrado. 14. Labiateae. An. A cad. Bms. Cienc., 38: 315- 326. M elhem, T. S., 1965. Pollen grains of plants of the Cerrado. 9. Leguminosae-Lotoideae, Tribes Galegeae and Sophoreae. An. Acad. Bras. Cienc., 36: 50 1-510. M elhem, T. S., 1966. Pollen grains of plants of t he Cerrado. 12. Cucurbitaceae, Menispermaceae, and . Moraceae. An. Acad. Bras. Cienc., 38:195- 203. Palacios, R., 1967. Morfologia ·e 1/ustraciones de los Granos de Polen de 162 £species de la Flora Arborea del Estado de More/as. Tesis, Escuela Nacl. Cienc. Bioi., Inst. Po litec. Nacl. (Mexico, D .F.), 125 pp. (see also, 1966, An. Escue/a Nacl. Cienc., Bioi., 16: 41- 169).

A.GRAl-IAM

360

Salazar Mallen, M., 1940. Estudio de los polenes de Ia atmosfera de Ia Ciudad de Mexico. Rev. Soc. Mex.Hist . Nat., l : 147- 164. Salgado-Labo uriau, M . L. and Va lio, 1. F. M., 1964. Pollen grains of plants of the Cenado. 8. Lyth raceac. Ret•. Btm. Bioi., 24: 439- 450. Salgado-Labo uriau, M. L., Vanzolini, P. E., and Melhem, T .. S ., 1965. Variation of polar axes and equatoria l diameters in pollen grains o f two species of Cassia. Grcma Palynol., 6: I 66-176. ·Santos, C. F. 0., 196 1a . Matfo/ogia c Valor Taxouomicv tia Polen das Principais Plantas Apicolas. Tesc, Escola Superior de Agricultura Luiz de Queiroz, U .S.P., P iracicaba, 92 pp. Santos,·c. F. 0 ., 1961 b. Principais tipos de polen encontrados em algumas amostras de mel. Rev. Agric., 36: 93-96. . Sorsa, P., 1969. Pollen morphologica l studies on the Mimosaccac. Ann. Bot. Fenn., 6 : 1- 34. Thanikaimoni , G., 1968. Morphologic des pollens des Menispcrmace es. Ins/. Fr. Pondichery Trav., Sect. Sci. Tech., 5: 1-56. . T schudy, R. H. and Tschudy , B. D., 1965. Modern fern spores of Rancho Grande, Venezuela. Acta Bol . Venezuelica, I: 9- 71. T sukada, M., 1963. Pollen morphology and identification. I. Eucaesalpinieae. Pollen Spores, 5: 239-

284.

Tsukada, M., 1964a. Pollen morphology and identification. 4- Cactaceae. Pol/en Spores, 6: 45- 84. T sukada, M., 1964b. Pollen morpho logy and identification. 3. Modern and fossil tropical pollen with emphasis on Bombacaceae . Pollen Spot·es, 6: 393-462. Urbina, M.,I906. Granos de polen de oyamctl. An. Mus. Noel. (Mexico), 3:293-297. Veloso, H. P. and Barth, 0. M ., 1962. Catalogo sislematico dos p olens das plantas arboreas do Brasil meridional. 1. Magnoliaccae , A nnonaceae, Lauraccae e Myristicaceae. Mem. Inst. Oswaldo Cruz, 60: 59-93.

Index1 Abies, 301, 303, 304, 308-31 I A. guatemalensis, 157 A. re/igiosa, 94 , 306, 308 Abronia, 68 Abtllilotr lridens, 164 A. lriquetmm, 126 Acacia, 8, 67, 146, 183 A. auguslissima, 164 A. constricta, 126 A. com igera, 123, 129, 160 A. costaricensis, 184 A.famesiana, 123, 160, 183 A. pemw/1/la, 160 A. pringlei, 160 A. sphaeroceplwla, 143 A. texetrsis, 126 Acaetra, 205 Acalypha, 146, 226, 227, 239, 261, 285-287 A. arvensis, I 76 A. di>•ersifolia , 194 A. macros/achya, 115, 177 A. skutchii, 151 ~ Acanlhocereus, 123 A. penlagonus, 123, 183 Acall/horrhiza warscewiczii, 251 Acer negundo, 157, 306 var. mexicanum, 162 A. rubra, 43 A. sacchamm, 306 A. skulchii, 302, 306 Achatocarpus nigricans, 126 Aclu·as, 101 A. zapata, 114-116 Aclzyranlhes, 1, 12 Acidocroton;_29 Acidoton, 8 Acisantlzera, 22 A. quadrata, 130, 186 Acoelonhaphe, 9, 30 Acrocomia mexicana, 121, 130 Acromia panamensis, 184 A. sc/erocarpa, 184 Acrostic/tum, 8, 235, 239, 254, 268,,285-288, 290

A. aureum, 139, 188, 191, 239,268 A. datreaefo/ium, 189, 214, 268 Acrosynantlws, 27 Actine/la clzrysanlhemoides, 133

Aclino.v/ell/011, 30 Adelia, 146 Adelobotrys, 31 Adenaria, 215 A . jloribunda, 179 Ado/phia infesta, 136 Aechmea magdalenae, 195, 196 Aeschynomme, 146 A. (llltericana, 183, 186 A. brasi/iana, 176, 183 A. compacla, 123 A. hi;pida, 190 A. sensitiva, 190 Africa (vegetation of dry regions), 67 Aga>•e, 62, 123, 135-137, 143, 144 A. obscum, 136 A. panamena, 183 A. xalapensis, 96 Ageratum, 130 Aguadulce (Panama), 210 Agua Sucia (Colombia), 206 Albizzia caribaea, 184 A. guadropele, 184 A. purpusii, II I, 126 Alchemi/la pectinata, 96 A. pinna/a, 163

A. l'lllcanica, 94 Alchichica (Puebla, Mexico), 88, 132, 135 Alchomea, 14, 22, 224, 226, 227, 233, 239, 261' 285--288 A. costaricensis, 261 A. f(f/ijolia, 101, II I, j15;1 I 7, I 55 Alclromeopsis, 27, 29 ..-_;/' - . . ' :- · .~· ~-- ·. A /faroa coslaricensis, !99-'

A. mexicana, 10,5 ""'Alibertia, 146, 226/252. A. edulis, 99, ·1;55, 194, 265. ·' · A/lamanda catltartj}a, 143 11 .' • • ·· : ' Allenrolfea, 68 . it ~ · Allophyl/us occidetii'alis, Jll5,.'193 . . · Alloplectus, 28 ·_' ·. ' •· · "·· ·-.. · .-• ·..-·.· · Almirante (Chiriqui Pfov.;i'anama ), 256 . ·:. Alnus, 55, 146,226, 2:l'i,2-n,':l57, 286-2~8;' · 301' 302, 304, 308-3fi .. . . ..·; A. arguta, 96, 162, 306 ··- ......~ ... A.ferruginea, 161, 257 Aloysia, 70 Alseis blackiana, 193

1 Where more than one spelling of a plant name occurs in the text, the first cited fotin bas been used for purposes of indexing; (f) designates a fossil fiom o r a geologic formation contain ing plant fossils.

362 Alta Verapaz (Guatemala), 152 A ltemalllhera, 233, 256 A.ficoidea, 176 A. repe1u·, 133 Alt itudinal (fo rest type, Lesser Antilles), 5 A/vamdou, 23, 29 A . amorplwides, 160 Amaioua, 30 A. corymbosa, 180, 181, 193 Amauoa, 24, 35, 36 Amarantlms, 146 · A. gregii, 143 Ambrosia, 253 A. CI/11101/CilSis, 143 Amerinmou brownii, 139 Ampe/oceras, 26 · A. lro/1/ei, 115 Amphi/opliiwn panicu/arum, 178-180 Amphipterygium adstringens, 152 Amyris, 21 A. chiapeusis, 159 Anacordiwn exec/sum, 193-197 A. occidenrale, !85 Anagollis pumila, 190 Ananos magdalenae, 196 Anchirherium, 209 Ancislranrhus, 25 Ancon Hill (Canal Zone), 245, 256 plant list, 186 Andira, 13, 35, 36 A. ga/eolliana, Il l, 162 A. inermis, 107, 180, 181, 196 Andropogou, 146 A. alrus, 131 A. angus/a/us, 183, 186 A. bicornis, J3 1, 176, 189 A. brevijolius, 176, 183, 186 A. g/omerarus, 133, 143 A. leucostachyus, 176 A. litoralis, 143 Aneilema kol'lviuskyana, 136 Anemia pasriuacaria, 183, 186 Anemopaegma orbicu/atum, 178- 180 Ange/onia, 22 Aniba, 24 Anuona,12 A. g/abro, 139 A. muricata, Ill A. purpurea, ll1, 180, 191 A . reticu/ata, 111 A. spraguei, 180 Anoda, 21, 146 Anthericum aff. leucocomum, 132 A. nanum, 132 Anthoplerus wardii, 260 Anthurium, 15, 231, 249

INDEX

Autig0110n, 70, 146 A. leptopus, 143 Antigua, 6, 23 Antil,les, 1-38 Alt itudes, 2 Climates, 2, 3 Soils, 3, 4 Vegetation Disjunctions, 29-31 Distribution patterns, 29-37 Origin, 16-17 Relationsh ips, 17-29 Types, 4-16 Volcanic activity, 4 Alllir/rea, 36 A peiba, 146, 21 5, 239, 285-287 A. aspera, 267 A. membranaceo, 241, 267 A. tibourbou, 179, 182, 184, 196, 21 5,

226, 227, 241, 267 . Aphanos/ephanus lwmilis, 133 Aphe/audra, 223 A. gigautif/ora, 161 A . incam ata, f98 A. sinclairiana, 194, 198, 251, 255 Apop/auesia paniculala, 152 Aplerio, 21 Aralia, 4 1 Arbultts g/ondulosa, 96 A. xa/apensis, 161 A rceu/obium, 30 A. bicarinatum, 14 Archaeollippus, 209 A rcoa, 25 Arctoslaphylos Iucida, 164 Ardisia, 21 A. alba, !57 A. compressa, 195 A. escallouioides, 159 A. hyalina, 104 A. ovandensis, 151 Arenaria, 23, 29 A. bryoides, 94, 163 A. lycopodioides, 96 A . serpens, 94 Argemone, 146 Arid Zones (North America, map), 64 Arislida, 67 A. barbata, 136 A. capillacea, 176 A. glauco, 136 A. jorullensis, 186 A. ternipes, 186 Aristolochia, 9, 146 A rrabidaea chico, 179 A. pacltycalyx, 180, 192

Artemhia, 67 Arthrostemma, 31, 146 Anhrosrylidium racemijlomm, 181 . Aruba (island, Caribbean), 19 Amndinel/a deppeana, 96 Asclepias, 146 A. curassaivica, 176, 177, 180 A. g/aucescens, 132 A. linaria, 137 A. t·osea, 132 A scyrum, 9 A. hypericoides, 96 var. hypericoides, 306 Aspidosperma, 30 A . mega/ocarpon, 115, 155 A splenium castaneum, 139 A ster, !46 A stragalus wootoni, 133 Aslrocaryum mexictlmtm, Ill A . slondleyanum, 188, 191- 194 Astronium graveo/ens, Il l, 115, !58 AtamiJ·quea emargitrala, 68 Ateleia, 26 Atlantic muck {Panama), 211,283 Atriplex, 12, 22, 67 A, pueb/ensis, 133 Afla/ea gomphococcb, 179 Aulomyrica tomelllosa, 182 Aurodendron, 27 Australia {vegetation of dry regions), 66, 67 A vicennia, 8, 12, 139, 213, 233, 235, 239, 249,

268, 283-287 A. bicilor, 187, 188 A. germinaus, 139, 182, 187, 188 A. nilida, 162, 182, 188, 268 Axonopus aureus, 176 A. capillaris, 184 A. centra/is, 176 Azuero Peninsula (Panama) 168, 169 .

Bacclraris, 70 B. confer/a, 96 B . heterophyl/a, 162 B. lrinervis, 161 B. vaccinioides, 164 Bacopa, 190 B. monieri, 145 BacMs baculifera, 111 B. balanoidea, 195 B. cohune, 111, 138 B. major, 187, 191 Bahama Bank, I Bahamas, 1, 7, 13, 19, 20, 21, 27, 28, 32, 34 Bahia de Cochinos (Cuba), 9 Bahia Salada (Mexico), 273

363

Baja Califo rnia, 62, 63, 65, 66, 68, 69 Baja pcrennifolia, 156, !57 Baja sicmprc- verde, 156, !57 Baja Vcrapaz {Guatemala), 152 Balboa (Can al Zone), 257 Plant list, 171 Balboa Heights (Panama), 169,212 Bald Hill (San Jose Island, Panama; plant list)

176 Banana plan tations (Panama), 174 B:1rahona P rovince (Hispaniola), 32 Barbados, I, 3 Barro Colorado Island (Panama), 171, 211 ,

214, 215,217,228,247, 251,253, 256, 257, 259. 260, 262-264, 266-268 Modern pollen rain, 225-228 Plant list, 179, 181, 196 Balis, 6, 12 B. marilima, 133, 143 Bauhinia, 13, 146, 192 B. a/bif/ora, 160 B. emarginala, 223, 236, 262, 285, 286 B. excisa, 177, 180, 181, 195 B . pau/etia, 160 B. thompsonii, 178, 180, 181, 195 Bauxite (ore, soils ; Antilles), I I, 12 Bayaguana-Hato Mayor (plains, Hispaniola),

33 Bay of Pigs (Cuba}, 9 Beata Island {Hispanio la}, 6 Befaria, 12, 30 B. glauco, 104 Begonia, 213 B.filipes, 189 Belwimia, 25 Bei/schmiedia, 21 B. anay, 117 B. mexicana, 117 Bellaco {Veracruz, Mexico), 120, 121 .Bell City {f), 40 Be/Ionia, 26 Beloperone, 70 Be/otia, 30, 146 B. cambellii, 155 B. mexicana, 156 Bembicidium, 25 Berberis, 30 Bercltemia scandens, 162 Bernardia, 27 Bernou/lia flammea, 111, 114, 11 5, 158 Bertiero, 35, 36 Bes/eria, 29 B. paucif/ora, 198 Betula, 55, 301, '304, 310, 311 Bidens squarrosa, 143 B. triplinervia, 96

364

INDEX INDEX

Billia hippocastanum, 157 Bisgoeppertia, 26 Bixa, 146 Blakea, 31 Bleclwm panamensis, 193· Bleplwridium mcxicanum, 155 Blcplwrodon mucromrlatum, 176 Bletia purpurea, 184, 186 Blighia sapida, .l6 Bocas del Toro (Province, Panama), 167, 169 Plant list, 188, 191 Bocas Island (Panama), 2 56 Bocconla gracill:r, 161 . Boehmerica cylindrica, 189 Boerhm•ia erecta, 126 Bogota Pla in (Colombia), 204, 205 Bolivar Trough, 209 Bombacopsis, 226, 285, 287 B. fendleri, 119, 196, 214, 257 B. quinata, 179, 182-184, 193, 194, 196, 197, 243, 257 B. sessilis, 179, 180, 181, 193, 197, 243, 257 Bombax barrigon, 191 B. e/lipticum, 11 5 B. emorgiuatum, 13 B. quinatwn, 182-184 ' B. sessile, 180, 18 1 Bonaire (Island, Caribbean), 19 Bonania, 26 Bonnet/a, 30 Bomia, 25, 28 B. daplmoides, 7 Bon·eria, 146, 213, 223, 252, 265 Borrichia, 23 B. /l'lltescens, 133 Bosque, 160 Bosque cauducifolio, 160 Bosque deciduo, 160 Bosque de pi no y encino, 161 Bosque esp inoso, 160 Bosque tropical decidua, J 59 Bouchea, 36 Bounet'ia densiflora, 184, 186 B.lzuanita, 159 B. /aevis, 13, 176, 178, 180 B. /atifolia, 176, 184, 186 B. ocymoides, 184, 186 B. parvifo/ia, 176 B. pumi!io, 176 Boute/oua barvata, 68 B. breviseta, 133 B. curtipendula, 132 B. gracilis, 132 Bouvardia longiflora, 137 B. scabrida, 136

Braclzypteris, 35 Brackish riparian forest (Panama), 175, 189 Brackish swamp forest (Panama), 1 75~1 87 Brassavola nodosa, 184, 186 Bravaisia, 30 B. integerrima, 162 Brickel/la, 70 Briza rotunda/a, 163

Bromelia,.l46 B. karatas, 183, 185 B. pinguin, 123 Bromus carinatus, 163 Bros/mum, 101, 195 B. a/icastrum, 99, 107, 1 II, 114- 11 7, 155, 158

B. guiancnse, 197 B. lenabammt , 109 Broughton/a, 29 Browal/ia, 24 B. americana, 176, 178 Brownea macroplzylla, 192, 197 Browneopsis exce/sa, 190 Brunella vulgaris, 96 Brunellia, 22 · B. costaricensis, 198 B. mexicana, 99, 104, 157 Brya, 8, 29 Buchenavia, 13 Buclmera, 22, 186 Bucida, 13 B. buceras, 162, 182 Buddleia, 23, 29 B. crotonoides, 161 B. ovandensis, 151 B. skutcltii, 161 B. atf. skutchii, 137 Buetlneria (see Byt/1/eria) Bulbostylis capillaris, 132 B. junciformis, 176 B. papillosa, 99 B. atf. paradoxa, 131 Bumelia, 2 1, 184 B. persimilis, J 16, 155, 158 Bunch grassland (Chiapas, Mexico), 154, .163 Bunchosia, 146 B. biocellata, 123 B. comifolia, 182 B.lanceolata, 11 5, 126 Burica Peninsula (Panama), 210 Burmannia, 21 Bursera, 8, 70, 235, 238, 239, 259, 285-288 B. bipinnata, 124 B. excelsa, !59 B. fagaroides, 123 B. simaruba, 111, 11 4-116, 124, 137, 155, 159, 182- 185, 259

B)'l'~anima ,

9, 223, 239, 285

B. crassi/olia, 99, 101, 102, 121, 124, 131, 160, 180, 181, 185, 186, 191, 263 JJ. drcssleri, 199 Byttneria ( Buettucria) , 146, 224, 226, 247, 267 B. acu/eata, 177, 180, 193

Cabomba, 145, 213 Cactus scrub, 4 Cae.mlpinia . 7, 8, 67 C. bonduc, 143, 182 C. cri~·w, 182, 183, 21 3 C. eriostachys, 182, 185 Caki/e lancco/ata, 143 Calamagrostis tolucensis, 163 Ca/apogonirm1 mucunoides, 184 Calathea, 163, 179, 215 Ca/atola !aevigata, 1 17 Calderonel/a syh•atica, 199 Ca!ea, 31, 146 C. integrifolia, 96 C. manicata, 96 C. prrmifolia, 178, 183 C. urticifolia, 96 Ctrlliandra, 8, 146, 222, 235, 262, 263, 285, 286-288 C. grandiflora, 164 C. houston/ana, 164 Cal/icarpa, 22, 36 C. aclimiuata, 178 Calolisiantlws, 24 Calophyllum, 14 C. bmsiliense, J07, 156 var. rekoi, 162, 198 Ca/opogonium mucrmoides, 176, 186 Calycogonium, 20, 24 Calycolpus warszewicziamrs, 180, 181 Calycophyllum, 30 C. candidissimum, J 58, 159, I84, 193 Calyptranthes chiapensis, 159 C. kanvinskyana, 104 Calyptronoma, 27 Ca/ytrocarpus, 30 Camaguey Province (Cuba), 31-33 Cameraria, 29 Campnosperma panamensis, 191 Canacoital (swamp vegetation; Chiapas, Mexico), 161 Cana l Zone Biological area (Barro Colorado Island), 214 Plant list, 179, 183, 186- 190, 192, 193, 196

365

Canary Islands, 33 Catw••alia, 7, 146, 223, 224, 226, 236, 262, 285 C. bicttrinata, 262 C. maritima, 142-144, 182, 183, 213 C. pcmamensis, 262 C. rosea, 182, 262 Canicula (warm, dry periods; Mexico), 80 Canna, 146, 190 Caper·ouia, 35 Capparis, 12, 226 C. baducca, l iS C. cynophalloplram, 182 C. inca11a, 137 Capraria bi/fora, 13 7 Capsicum, 36 C./rutescens, 176 Ca)Julines (Veracruz, Mexico), 122 Campa guianensis, 188, 191, 195 C. slater/, 214 Cardiospermum, 146, 241, 266 Cai'ex, 146, 163 C. chiapcnsis, 152 Caribea, 25 Carica papaya, 175, 177 Car/owrightia, 70 Car/udo••ica palma/a, 175, 177 Camegia, 62 Carpimrs caroliniana, 104, 105, 160, 302, 306 Carpodiptera, 23, 26, 35 C. ameliae, 11 6 Carvajal (Mexico), 272, 273 Carya, 301, 302, 304, 307, 310, 311 C. i/linoensis, 306 C. mexicana, 307 C. myristicifolia, 306 C. ovata, 306, 307 Casasia, 25, 29 Cascade Mo untains (Ca lifornia- Washington) 69 Casearia, 13, 34, 36, 146 C. banquitana, 182, 185 C. commersoniana, 178 C. myriantha, 178 C. nilida, 124, 143, 160, 177, 179, 182, 185 C. sy/vestris, 178 Cassava (Manihot), 261 Cassia, 34, 67, 146 C. chamaecristoides, 142, 143 C. cinerea, 143 C. diphyl!a, 13 1, 186 C. grandis; 155 C. mosclrata, 191 C. oxyplrylla, I 60 C. reticu/ata, 191, 192

366

INDEX

Cassia tager(4i8 6 Cassipourca, 35, 224, 249, 265 C. elliptica, 18 1, 188, 265 Castalia, 190, 213 C. amp/a, 190 Castanea, 55, 56, 301, 310, 311 Coste/a, 68 Castilla e!a~tica, ttl, 115,116, 18 1, 196 C. panameusis, 181, 196, 215 Castilleja, 30, 94 C. longibracteata, 96 Catalpa, 29, 36 Catcmaco (Veracruz, Mexico), 85 Catesbaea, 7, 24 Cativos (Prioria stands, Panama), 214 Catopheria chiapensis, 152 Catopsis, 223, 231, 251 C.morrenicma, 231, 251 Cau/antlurs, 68 Caulcrpa, 144 Cavanil/esia, 194, 226,257,285, 287, 288 C.lry/ogeiton, 244, 257 C. platanifo!ia, 179, 193, 194, 195, 196, 244

Cavendislria guatema/ensis, 158 C. longif/ora, 260 Ceanothus, 70 C. coeru/eus, 161 , 164 Cecropia, 146, 179, 196, 215, 227, 235, 267 C. araclmoidca, 178 C. longipes, 179, 192, 215 C. mexicana, 179, 215 C. obtusifolia, 179, 192, 195 C. pe/tata, 159, 178, 192 C. spinescens, 178 Cedre/a, 21, 36, 146 C. angustifolia, 184, 191, 192 C. jissilis, J84 C. oaxacensis, I 59 C. odorata, 114, 115, J 94 C. tonduzii, I98 Ceiba, 226, 243, 258, 285-287 -c. pentandra, 11 J, JJ 6, 158, 179, 184,

193, 194, 195, 197, 258

C. rosea, 258 Ceibadales (marine grassla nds), 144 Celtis, 21, 301 , 308-3JJ C. iguanaea, 124, I84, 306 C. spinosa, 68 Cenclrrus, 7, I46 C. brownii, J76 C. echinatus, 176, 182 Centaurium, 27 Centradenia sa/icifo!ia, 104 Central D epression (Chiapas, Mexico), 149I53, 159, 160, 162

IN DEX

Central Highlands, Plateau (Chiapas, Mexico), 149, 150, 152, 153, 156, 157, 1 ~0- 1 63 Ceutrolobium paraense var. orenocense, 195 C. patinense, 195 Centropogon, 24 C. cordaltts, 157 Centrosema pubescens, J76 Centrosperma, 146 Centwrcu/us pemandms, 190 Ceplraelis, 3 1, 36 C. axil/oris, J 57 C. correae, J99 C. elata, 157, !98 C. glomem/ata, 197 C. rigidifolia, 199 C. tome/llosa, 109 Ceplra!ant/ws, 30 Cerastirmr oritlra/es, 94 C. vulcanicum, 94 Ceratoplryllum demersum, 145 Ceratopteris, 190 Ceratopyxis, 25 Ceratozamia mexicana, 117

Cercidirmr praecox, 68 Cercis canadensis, 302, 306 var. mexicana, 307 var. occidentalis, 307 var. texensis, 307 var. typica, 307 Cereus, 8 C. costaricensis, 183 C. pentagonus, 183 Cerrado, 121 Cerro Azul (Panama; plant list), J99 Cerro de San Cristobal (Mexico), 105 Cerro H oya (peak, Panama), 168 Cerro Jefe {Panama ; plant list), 199 Cerro Sapo {Darien, Panama; pla nt list), 197 Cerro Tacarcuna (Panama), 168 Cespedesia macroplrylla, 197 Cestrum, 146, 196 C. endliclreri, 104 C. f asciculatum, I 04 C. guatemalensis var. gracile, 161 C. latifoliwn, 175, 177 Clraenactis, 70 Clraerrocephalus, 3I Clraetolepis, 30 Chaetoptelea ( Ulmus) mexicana, 156 Chagres River, watershed (Panama), 210, 2!1 , 263, 264, 282, 283 Clramaedorea altemans, I l l C. concolor, I 57

C. ernesti-augusti, 111 C. lindeniana, Il l C. lunata, !1 6

C. oblongata, I l l C. cf. pacaya, 193 C. tepejilote, I l l C. weudkmdiana, 193 Clramae.ryce buxifo/ia, 143 C. lrirta, 176 C.lrypericifa/ia, 176, 184 C. lryssopifolia, 131, 176 C. tlrymifo/ia, 176 Changuinola (Bocas d el Toro Prov., Panama), 169 Clrara kerro1â&#x20AC;˘eri, 189 Clrari{(lrtlrus, 15, 31 Clrascotlreca, 26 Chayote (Cucurbitaceae), 241, 260

Clrei/antlres microplrylla, 96 Clreuopodium, 146 C hiapas Plateau, H ighlands, 149, 152 C h iapas(Sta te, Mexico), 149- 165,301, 302, 310 P hysiographic regio ns, 149 Map, 150 Phytogeography, 150-153 Vegetation formations, 154-164 D iagram, 154 B unch grassland, 154, 163 Coastal strand , 151 , 154, 163 Evergreen cloud forest, 151, 152, ! 54, 157, 158, 163 Evergreen, sem i-evergreen seasonal forest, 151, 153, 154, 158, 159 Herbaceous swamp, 154, 163 _ Lower m ontane rain forest, 151 , 153, !54, 156, 158 Mangrove swamp, 151, 154, 162 Montane rain forest, 151, 153, !54, 156, 157 Palm forest, 15 1, 153, 154, 162 Paramo, 154, 163 Pine-oak forest, 151, ! 52, !54, 161 , 163 Pine-oak-Liqrridambar forest, I 51l54, 160, 161, 163 Savanna, 152 Second-growth, successiona l, s hrub association, 163, 164 Short-tree savanna, I5 l , !53, 154, 159, 160 Swamp and lowland riparian forest, 154, 161 , 162 T emperate riparian forest, 154, 162 Thorn woodland, 151, 154, 158, I 60 Tropical deciduous forest, 151, 154, 159, 160 ' Tropical rain forest, 153- 156, ! 58 Chihuah ua (Mexico), Chihuah uan desert, 6366, 68-71, 308

367

Clrimap!Jila, 30 C. maculara, 96 Cltiococca alba, 178, 180- 182, 192 C.plraeuostemou, 161 Clrioue boxifolia, 199 C. clrambersii, 193 C!tiramlwdell(/ron pemadactylon, 157 Chiriqui (Province, Pana ma), 167, 169, 210, 2 11, 256 P lant list, 198 Volcano, 257 Clr/oroplrom, 2 1, 35 C. tiuctoria, 116, 117, 124, 126, 184 Clrome/ia, 24, 253, 266 C. recordii, 193 C. spinosa, 192, 193, 197 Clrrysactinia mexicana, 136 Clrrysoba/anus, 35 C. icaco, 7, 142, 143, 182 Clrrysocltlamys, 24 Clrrysoplry!lrmt, 34, 36, 196 C. mexicanum, 156 Clwysotltemis, 27 Clwsquea simp/icifo/ia, 181 Cibao (river, Hispaniola), 33 Cicnaga Zapata (marsh, Cuba), 9 Cienfrregosia, 30 Cimramodendrou, 29 Cinturon N eovolcanico (Mexico), 73 Cionoci.1yos, 27 Cirsium, 146 Cissampelos, 146 Cissrrs, 222, 241 , 268 C. erosa, J 78 C. rlrombifolia, 175, 177, 178, 180 C. sicyoides, 175, 177, 180, 183, 185 Citlwrexy!um, 70 C. berlandieri, 126 C. caudatrrm, 187, 189 C. domre/1-smitlrii, 160 . C. ellipticrrm, 124, 143 C. lrexmrgrrlare, 126 Cladiwn, 9, 15 C. jamaiccnse, 163, !90 Claiborne (f), 39, 40, 55 C/avija, 30 C. mezii, 194, I97, 198 C/eidion oblongifolium, 156 C/eome, 146

C/erodendrrun ligrrstrimrm, 139 C/etlrra, 27, 36, 101 C. lantana, 157 C. macroplrylla, 99, 104 C. matudai, 151 C. o/eoides, 157 C. quercifolia, I 05, 306

368

Clethra suaveolens, 160 C. theaoides, 158 Cleyera, 22 C. scrrulata, 104 C/ibadium appressipi/wu, 177, 179 C. arboreum, 164 C. /eiocarpum, 175, 177, 179, 192 Clidemia, 21, 146 C. OC/0110, 177 C/itoria ga)•a11eusis, 186 C. portobelle11sis, 178, 180 C. mbiginosa, 176, 184, 186 Cloud forest Antilles, 5 Chiapas (Mexico), 157 Panama, 175, 198, 199 Veracruz (Mexico), I03 C/usia, 15, 110, 189, 190, 192, 193, 197, 198, 199,215 C.jlava, 152, 159 C. sa/vinii, 119 Cnemidm·ia, 255, 268 C11eorum, 30, 33 C11estidium rufescens, 178, 180, 181, 193 C11icus jorulleusis, 94 C. niva/is, 139 Cnidoscu/us, 1, 143, 146 Coahuila (Mexico), 307 Coal Mine Ridge (California; arid vegetation), 69 Coastal formations (vegetation, Antilles), 5- 8 Coastal strand (vegetation, Chiapas, Mexico), 15 1, 154, 163 Coatzacoalcos (Veracruz, Mexico), 106- 109, 131, 302, 308 Coaxana ebracteata, 164 Coccocypselum, 13 1 C. herbaccum, 198 C. hirsutum, 104 Cocco/oba, 13, 31, 114, 181,222,226, 333, 265 C. acumi11ata, 192 C . barbade11sis, 102, 121 C. caracasana, 191 C. corona/a, 185 C. cozumelensis, 152 C. dariene11sis, 193 C. tuerckheimii, 195 C. uvifera, 7, 142, 143, 182, 183, 213 C. waitii, 185 Coccothriuax, 9 Coch/ospermum, 146 C. vilifo/ium, 159, 175,177, 182-185 C. wil/iamsii, 197 Cochrane glaciation, 206 Cockpit country (Jamaica), 11- 13 Cocle (Province, P anama), 167, 169

INDEX Plant list, 199 Coc-os nucifera, 175, 182 Codiaeum, 261 Codanantlze, 24 CoeffiCient of similarity (for vegetation of dry regions), 61, 63, 65-67, 69, 70 Coeloneuru1n, 25 Cofrc de Perote (Veracruz, Mexico), 94 Coix /aclzryma-jobi, 176, 193 Coldeuia, 68 Colima (Mexico), 69 Colipa (Veracruz, Mexico; soil analysis, vegatation profile), 100, 116 Co/ogan ia, 131 C. procumbens, 132 Colon (city, province; Panama), 167, 169, 210,212 Plant list, 199 Col11brina, 7, 34 Colunmea, 22 Combrelum, 146, 223, 249, 259 C. decandrwn, 181 Comision de Dioscoreas, 91 Commelina, 146 C. diffusa, 132 C. erecta, 143 Comocladia, 8 C. eng/eriana, 124 Compsoneura, 222, 226, 235 C. sprucei, 264 Condalia, 68 C. mirandana, 137 Cannarus panamensis, 178, 180, 181, 194 C. williamsii, 194 Conocarpus, 8, 35, 139, 213, 235, 239, 249, 259, 283, 285-287 C. erectus, 139, 162, 182, 187-189, 259 Conostegia, 22, 146 C. arborea, 104 C. speciosa, 132 C. xa/apensis, 102, 179, 197, 198, 215 Conyza, 146 Copaifera, 35, 235, 237, 262, 285-288 C. aramatica, 190 C. panamensis, 190 Copemicia, 9 Core/torus, 177 Cordia, 1, 146, 215 C. alba, 126 C. alliodora, 11 5, 158, 159, 177-180 193, 196, 215, 222, 226, 227, 249, 258 C. bicolor, 178, 180, 181 C. boissieri, 126 C. curassavica, 160 C. dodecandra, 123

INDEX

C. dwyeri, 199 C.ferrtlgiuea, 178 C. panamaensis, 178, 183 C. porcata, 199 C. pringlei, 124 C. spinescens, I 78 Cordillera Central, Haiti, 32 H ispaniola, 10, 14, 32-34 Cordillera de Talamanca (Panama), 168 Cdrdillcra Septentrional (Hispaniola), 33 Cordilleran mountains (Panama), 211 Cordoba (Veracruz, Mexico), 111- 114 Cordon littoral, 163 Coreopsis, 30 Com11s, 302 C. disciflora, 96, 160, 306 C. excelsa, 96, 162, 306 C. florida, 105 subsp. uribiniana, 306 Conu1tia, 22 Corozal (Panama; plant list), 196 Corozo o/eifera , 191 Corylus, 55 Cosamaloapan (Veracruz, Mexico), 129 Cosmib11ena paludicola, 226, 253, 266 Costu.v, 146 C. 1111/aiiS, 197, 198 Coumarowza pauamensis, 196 Couroupila, 223, 224, 241, 249, 262 C. darienensis, 195 C. guianensis, 262 C. panameusis, 195 Co11rsetia axil/oris, 126 Co11ssapoa panamensis, 180, 18 1 Coussarea, 30 Co11tarea hexaudra, 124, 189 Co11toubea, 24 C. spicata, 176, 184, 186 Coyame (Veracruz, Mexico), 107 Crassostrea virgiuica, 272 Crataegus pubescens, 161, 162, 306 Crataeva, 27 C. tapia, Ill, 124 Crescentia a/ata, 123, 160 C. cujete, 101, 121, 160 Cressa, 67 Crimm1 erubescens, 145, 189 Cristobal (Panama), 212 Crossopeta/um Jatifolium, 142, 143 Crotalaria, 143, 146 C. pi/osa, 176, 186 C. pterocaula, 186 C. sagillalis, 132 Croton, 8, 17, 34, 146, 261 C. ciliato-glandulosus, 137

369

C. dioicm, 133 C. glalldu/osepalus, 124 C. guatemalensis, 160 C. nitens, 99, 114, 126 C. pt/1/CIOIIIS, 124, 143, 183, 213 C. repen.r, 99 C. lrinitatis, 186 Cn1sea, 146 C. ca/ocepha/a, 96 Cryopsamment (soil type; Veracruz, Mexico), 140 Cryosapltila, 231, 251 C. ll'arscewiczii, 25 I Cryptallllta albida, 68 Cryptorlti:m, 25 Cuba, I, 2, 4, 7, 10, 12-14, 17, 19-21, 25- 33 34, 36, 37 Cubacroton, 25 Cubantlws, 26 Cucaracha (f; Oligo-Miocene, Panama), '209, 310,31 1 Cuchumatan Massif (Chiapas, Mexico), 151 Cuesta de Maltrata (Veracruz, Mexico), 132 Cuicatlan (Mexico), 64, 66, 71 Cui de Sac (geographic district ; Haiti), 8, 33 Co lebra (f; Oligo-Miocene, Panama), 310, 311 Cupania, 223, 226, 266 C. alf. deutata, 110 C. del/lata, 109, 110, 11 5, 116, 126, 160 C. fulvida, 178 C. macrophy/la, 124 Cup/tea, 146 C. hyssopifolia, 162 Curacao (island, Caribbean), 19 Curate/fa, 26, 185 C. americana, 101, 102, 121, 124, 130, 132, 160, 185, 186 Curcu/igo scorzoueraefo/ia, 176 Curtia tene/la, 176, 186 Cuscuta salina, 133 Cyathea, 14, 308 C. costariceusis, 99 C. fluva, 104 Cyathula, 29 Cybiauthopsis, 26 Cydisla, 146 Cymbocatpa, 25, 29 Cymbopetalum baillonii, 109 C. penduli/lorum, 109, !56 Cymopolia barbata, 144 Cynometra retusa, 109 Cyperus, 138, 146, 163 C. articulatus, 143 C. diffusm, 176, 178, 180, 184, 186 C.flavus, 176 · C. giganteus, 138, 189, 190

INDEX

370

Cyperus ligularis, 143,184, 186 C. lttzttlae, 189 C. seslel'ioide.,, 132 C. teuerrinws, 186 Cyrilla, 22 Cyrtocarpa, 70 Oacryode.l', 13, 14, 24, 36, 37 Oacty{aeua, 30 Dalbergia, 8, 12 D. brownei, 118, 182 D. ecastopltyflum, 139, 183, 189,213 D. glabra, 124 Dafea, 146 D. elata, 117 D. melantlw, 136 Dalecltampia, 28 D. tiliifolia, 115, 177 Dauaea, 155, 285, 286 D. nodasa, 196 Daplmopsis, 22 D. bre11i[alia, 124 Darien (Province, Panama), 167, 169- 171, 174, 2 11, 237, 25 1, 260 Plant list, 183, 185, 187-195, 197- 199

Dasyliriou acrotriche, 136 Dasytropsis, 25 Davilla, 27, 146 D. a;pera, 177, 179- 181 D. Iucida, 111, 179- 181 Deciduous forest (Chiapas), 160 Deciduous seasonal forest Antilles, 4 Chiapas, 159 Panama, 175, 184, 185 Declieuxia, 30 D. mexicaua, 186 Delterainia, 30 D. matudai, 15 1 Dendrocousinia, 26 Dendropanax, 36, 41,44 D. arboreus, 101, 109-11 1, 116,215 Dendropemon, 22

Dendropthera, 22 Deppea grandif/ora, 105, 158 D. purpusii, 104 Depresion Central (Chiapas, Mexico), 15 1 Desmodium, 146, 177

D. adsceudens, 115 D. augustifolium, 176, 185 D. barbatum, 176, 184, 186 D.

CO/IU/11,

175, 177, 180

Desmopsis, 30 Dia/ium guianense, 107, 109, I 10, 155

INDEX

Dialyuntltem, 234, 235, 264, 285-288 Oicanopteris flexuosa, 189 Dicemtlterium, 209 Dichondra argentea, 133 Oichromena cilia/a, 132, 176, 178, 180, 184,

Dry e••crgrccn woodla nd, 4 Dry rainforest, 4

Drymonia, 24 D. spectabilis, 198 Dl')'ophy/lum, 44, 46 D. tennes.leemis, 42 Dryopteris gongylodes, 189 D. serrata, 189 Dukea panamensis, 199

186

Dictyoxiphiwtl, I 96 Didymopauax, 15, 28,2 15 D. 111orototoni, 177- 18 1, 184, 196 Dicj}imbacltia, 188, 191, 195, 196 D. oerstedii, 196 Digitaria sanguinalis, 116 Oi(){·{ea, 36 D. altissi111a var. mcgacarpa, 178, 183 D. megacarpa, I 78, 183 D. rej/exa, 178, 180 Diodia rigida, 132 Oioon edule, 124 D. spinulosum, 152 Oioscorea, 146, 175, 177 D. mexicmw, 11 5D. sapindoides, 176, 184, 186 Diospyros, 34, 302 · D. digyna, 116, 139, 306 D. riojae, 104, 306 Dip/to/is, 13, 23 Oiphysa floribtmda, 96, 160 D. robinioides, 184 Oipterodendron costaricense, 196 Dipteryx panamensis, 195, 2 14 Disciplwnia, 30 Distichilis, 7 D. spicata, 133, 134, 163 Disturbed forest (Panama), 173, 174

Dilla, 28 Dodouaea, 1, 67 Doerpfeldia, 25 Dogtooth limestone, 1

Oolichos labfab, 177 Doliocarpus, 28 D. dentallts, 181, 194 D. major, 194 D ominica, 3, 4, 9, 24 Dominican Republic (see also Hispaniola), 8, 9, 19, 33 Draba jorullensis, 139 D. myosotidioides, 139 D. volcanica, 163 Dracena, 30, 33 D. cubensis, 33 Drepanocarpus, 8, 35, 223, 226, 262, 285, 288 D. funatus, 237, 243, 262 Drimys granadensis, 157

Drosera, 9, 22 Dry evergreen forest, 4 Dry evergreen thicket, 4

' I

Durango (Mexico), 69, 70, 308 Dussia, 24, 30 D. mexicana, 104, Ill, 117 Dyssodia setiflora, 136

! I

Early secondary forest (Panama), 175, 177- 179 Eastern highlands (Mexico; see also Sierra Madre), 149, 150, 152, 153, 156, 162 Ecltinocactu.,, 137 Ecltinoch/oa colomm1, 176, 193 Echinodoms, 190 Echinolaena polystachya, 145

Echites, 22 Eclipta alba, 176, 178, 180, 189, 193 Ehretia, 22, 23, 36 Eichlwmia, 35, 213, 255 E. azurea, 189, 190 Eknumitmthe, 26 Ekmanioclwris, 25 Elaeagia, 30 Elaeodendrou xylocarpttm, 182 El Baru (mountain, Chiriqui Prov., Panama; see also Volcan de Chiriqui), 211 Eleocharis, 15 E. elegans, 145 E. interstincta, 132, 138, 186 £. mutata, 145 Elephamoptts mol/is, 176 Eleusine indica, 175, 177, 180 Eleutheranthera ruderalis, 176, 178, 180 Elfin fo rest, woodland Antilles, 5, 11, 15 C hiapas (Mexico), 157 Panama, 175, 199 Veracruz (Mexico), 119 Elfeanthus capitiltus, 119 Elle Valle de Anton (Panama), 260 El Sumidero (Chiapas, Mexico), 15 1 El Valle (Cocle Prov., Panama), 256 Plant list, 199 Elvira, 30 El Yunque (mountain, Puerto Rico), 14 Enal/agma fatifolia, I J6, 182, J88, 191 Ence/ia, 62, 68 Engelhardtia, 44, 46 E. mexicana, 105

371

Enicostemtt, 24 Enneapagon tlesiYJttxii, 68 Enriqui llo Basin ( Hispaniola), 2, 3, 6, 8, 12, 33 Entala gig(ls, 182 E111erolobiw11 cycfocarpum, 123, 158, 184, 19 1, 193 Eocene Oo ras Claiborne (Mississippi Embayment), ,39, 40, 55 Gatunci llo (Panama), 3 10, 311 Jackson (Mississippi Embayment), 40 Los Cucrvos (Colombia), 3 11 Mirador (Colom bia), 31 1 Mississippi Embayment, 39, 54, 55, 301 Paleoclimates, 39, 56, 57 Wilcox (M ississippi Embayment, U.S. Gulf Coast), 39, 40, 55, 30 1, 31 1

Eosauthe, 25 Ephedra, 61 E. aspera, 65 Eragrostis, 146 E. amabifis, 182 E. domiugensis, 143 Erblichia xylocarpa, 155 5rcchtites hierac1[olia, 176 Erigeron bonarieu.vis, 176, 178, 180 Eriacau{ou, 30 E. sdtietfeanwtl, 190 E. seemannii, 190 Eriogo1111111, 70 Eriape , 30 Eriosema, 26, 146 Erithallis, 23 E.fruticosa, 7 Emodea, 7, 23 Erodium cicutinum, 133 Eryngium w rlinae, 132 E. protea/lomm, 94 Erythea, 10 Erythraea macrautlw, 96 Erythrina, 146,213, 222, 237,262, 285, 287 £. chiapensis, 160 E. costaricensis, 237 £ . glauco, 190, 191, 23 1, 237, 262, 285 E. goldmauii, 152 E. herbacea, 306 Erythroxylum, 9, 22 E. areolatum, 124, 136 E. mexicauum, 184 Escltscholzia, 70 Esenbeckia, 22, 23, 29 E. berlaudieri, 137 Espadaea, 25 Espartal (Spartina grassland), 133, 134 Euchorium, 25 Eucnide, 10

372 Eugenia, 7, 17, 34, 146, 198 £. acapulcensi.v, 159 E./iebnumii, 124, 126 £. mexirana, 105 £. origanoides, 180, 18 1, 183 £. l'lll'CIIii, 152, 157 £. si/tepet·tuw, 151 £. tonii, 152, 158 E. ll'lmciflora, 104 Euleria, 25 Eupatorium, 146 £. amygdalinum, 186 £. aschenbomimwm, 96 E. billbcrgiammr, 180 E. espiuosarum, 137 E. i1'esincoides, 175, 177, 180, 193 £. macrophyllum, 175, 177, 180, 193 E. microsrcmou, 115, 177, 180, 193 E. morifolium, 96 E. odora/11111, 175, 177, 180, 193 E . siuc/airii, 177, 180 Euphorbia, 1, 146 E. antisypltilitica, 65 E. buxifolia, 143, 144 E. glomifera, 184 E. ltyssopifolia, 176 Eurotia, 68 Eusroma, 22, 23, 29 Evergreen bushland, 4 Evergreen cloud forest (Chiapas, Mexico), 15 1, 152, 154, 157, 158, 164 Evergreen seasonal forest Antilles, 4 Panama, 175, 197 Evergreen, semi-evergreen seasonal forest Chiapas (Mexico), 15 1- 154, 158, 159 Panama, 172 E•olvulus, 186 E. filipes, 184, 186 Exostema, 22 E. mexicanum, 115 Exotltea, 23 E. copa/illo, 11 5 EJ•senltardtia, 62 E. adenostylis, !59

Fagus, 30!, 304,308- 31 1 F. grandifolia, 306 var. mexicana, 307 F. mexicana, 104, 302, 307 Faramea, 226, 253, 266, 286-288 F. jefensis, 199 F. luteovirens, 194, 197, 198 F. occidentalis, 156, 194, 197, 198 Festuca, 139

INDEX F. amplis.vima, 163 F. tolucensis, 163 Ficus. 14, 34, 44, 146, 181, 190, 193, 196, 215, 22(, 232, 235,267 F. bullenei, 180, 181 F. campbellii, 195 F. citrifulia, 178, 195 F. cooki, 115 F. cotinifolia, 124 F. crassiuscula, 195 F. dugandii, 195 F. glabmta, 196, 214 F. glaucescen.f, 138 F. iusipida, I I , J 16, 139, 192, 195, 196 F. lapatltifolia, 11 7 F. /ea•ensii, 182 F. maxima, 10 1, 124 F. uyinphaefolia, 193, 197 F. obtusifolia, 124 F. popenoei, 180 F. srandleyana, 178 F. tecolutensis, I l l, 114, 115 F. trigona/a, 182, 195 Fimbristy/is wmua, 186 F. castanea, 133 F. miliacea, 176, 178 F. sparhacea, 133, 143 Flora Veracruz Project, 91, 302 Florestina, 10 Floureusia, 62, 68 F. cenma, 65 Fo liar physiognomy, -39, 41 , 46-55, 57 Fardrhammeria, 22, 23, 29 Forestiera, 23 Farsteronia , 22 F. viridescens, l ll.l Fort Gulick (Panama), 171 Fort Randolph (Panama), 214 Fort Sherman (Panama), 171, 214, 259 Fouquieria, 65 F. campauulata, 65 Frankenia, 67 Franseria, 68 Fraxinus, 9, 30, 33, 69, 304 F. greggii, 65 F. schiediana, 306 F. uhdei, 160 Freshwater marsh (Panama), 175, 189- 190 Freshwater riparian forest (Panama) 175, 192, 193 Freshwater swamp forest (Panama), 170, 175, 190-192 Freziera, 15, 27 Fuchsia microphylla subsp. aprica, 158 subsp. quercetorum, 161 F. paniculata, 158

INDEX Fuerle.l'ia, 25 Fuireua, 132 F. umhel/ata, 189

Gage's Soufrierc (Montserrat, Antilles), I I Ga illard Cut (Panama), 311 Ga lapagos Islands, 35 Galeria forest (Panama), 174 Galium tmcinulatum, 96 Gamboa (Panama), 283 Garcinia, 35 Garrya, 22, 23, 29 G. lmmfolia, 161 Gatun Basin, City, Lake (Panama), 207, 208,

210- 213,221, 228,229,237,245,247, 253, 255,258,259, 261,264,265,289,310,31 1 Map, 216, 217 Modern pollen rain, 225-228 Plan t list, 189-190 Po llen d iagrams, 222- 224 Sea-level change, 282-293 Vegetational history, 233- 248 Gatun formation (f; Miocene, Panama), 310, 311 Gatuncillo formation (f; Eocene, Panama), 310, 31 1 ~ River (Panama), 282 Gaultheria, 30 G. acumiuata, 306 G. ltidalgensis, 306 G. lrirtifolia, 306 G. nitida, 119 G. odarara, 161, 306 Gaussia, 13, 27, 32 Geissomeria, 31 Geuipa americana, 109, 183 G. caruto, 102 Genlisea, 30, 35, 36 Gentiana pumilio, 163 Gent/eo micralllha, 158 G. venosissima, 159 Geoffroea inermis, 192 Georgetown (Br. Guinea), 206 Gerardia, 9, 22 Gesneria, 15, 25 Ghinia, 23 Cilia, 10 Gilibertia, 36 Ginoria nudiflora, 10 1 Gleicltenia f/exuosa, 189 Gliricidia, 146 G. sepium, 142, 159, 196 Globigerina rubescens, 276 Glycydendron, 223 G. amazonicum, 239, 241, 261

373

Gnat>lurlium bmcltypl<'rttlll, 96 G. iiiUYIIilllllll, 139 G. oxypltylltim, 139 G. popocatepecianum, 139 G. wdi·ani!-tmr, 163 Gocllllatia, 26, 70 Cudmauia acst'll/ifolia, 159 Goerziel/a, 25 Goetzia, 27 Golfo Dulce, 251 Gomp/trena, 233 G. tlisper.wt, 133 Gouoca/yx, 31 Couolobus, 24, 146 Gonzalagunia rudis, 177, 179, 192 Gossypiospermum, 30 Gouauia, 146 C. po/ygama, 178, 181 Gouinia, 70 Grajfenriedia, 22 Grand Etang (Grenada), 10 Grand Savanna (Dominica), 9 Grass-sedges on steep slopes (Panama), 173, 174 Grassy Plains (Panama), 173, 174 Great Basin, 64, 66, 67, 71 Green River (f), 45, 46 Grenada, 1-4, 7, 10, 15, 19 Grenadines, 13 Grias, 31 C. fendleri, 196,214 Crimmeodendron, 27, 29 Gros Piton (St. Lucia, Antilles), 13 Guadeloupe, 3, 9, II, 19, 20, 23, 24 Guaiacum, 70 G. SOIIC/11111, 152 Guamarela tuerchheimii, 161 Gum·ea, 22, 35, 109 G. bijuga, Ill G. chidlon, 105, 109, 110, 115 G. culehmna, 195 G. excelsa, 155 G. glabra, I l l G. guara, 192, 195 G. guidonia, 192, 193, 195 G. multiflora, 195 G. tonduzii, 109 Guattaria, 28 G. amplifo/ia, 109, 110 G. auomola, 155 Guazuma, 22, 146 G. ulmifolia, 116, 11 7, 126, 177, 179, 183, 185,215 Guel/arda, 8, 22 G. combsii, 152, 158 C. elliptica, ll5, 124

374 GuNtarda odorma, 183, 185 Guilcmdina, 7

Gulf Coastal Plai n (Mexico), 149, ISO, 153, 158, 163 Gumnia coccinea. 175, 177, 180, 193 Gustavia, 195, 216 G. nona, 193 G. supcrba, 181, 192, 193, 195-197 Gmierrezia, 68 Gyminda, 22, 23 Gymnanthes, 8 Gyumopodium antigonoides, 152 Gymuospemw, 70 Gynerium ,·agilfatwn, 178, 189, 192 Gynoxys, 31 Cyran!hera darieueusis, 223, 247, 258 Gyro/aeuia, 29

Habenaria, 190 H. paucijlora, 176, 184, 186 Haemaloxy/on, 8, 9 H . brasiletto, 124 H. campechkmw11, 162 Haiti (see also Hispaniola), 8, 19, 32, 33 Haitia, 25 Ha/enia bret•icomis, 96 H. tllldicau/is, 94 H. pauciflora, 94 Halimeda opuntia, 144 Ha/imium, 30, 36 Halodule wrightii, 144, 145 Halophilo decipiens var. pubescens, 145 Hamamelis mexicana, 307 H. virginico, 302, 306, 307 Hamelin, 146, 183 H . axillaris, 177, 179 H. patens, 124 Hampea, 242 H. integerrima, 99, 117 H. longipes, 157 H. micrantlta, !99 H.uutricia, Il l Haplopappus stolouiferus, 163 Hamackia, 25 Harpalyce, 30 Hasseltia dioica, 155 H : jloribunda, 177-179, 192, 194, 197 H. rigida, 199 Jfauya elegaus, 159

Havana {city, province; Cuba), 3, 31, 32

..f. Haystack mountains (Cuba, Puerto Rico), 12 Hebestigma, 25 H ebracantltus silvaticus, 194 · H edhtia, 62, 135, 136 · -H: roseana, 136

INDEX

Het~I'O.I"fl/11111,

231, 259, 285, 286

H. mcxicamtm, 157 Nei.vteria, 35, 36 H.lniiJ:ipe.,·, 193, 197, 198 Jleliconia, 146, 163, 179, 188, 191, 192, 2 14,

215 fl. bikai, 10~ H. imbricota, 177, 180 H. lotispathu, 115, 177, 180 H. mariae, 175, 177, 180 H. meta/fica, 194, 197 H. schiedeana,· 104 H. ••agiua/is, 194 He/iueres, 22, 36, 213 H . guazumaejolia, 179, 2 15 N e/ietta, 30 H e/iocm·pus, 146, 215 H . popayaumsis, 177, 179 H eliotropium, 12 H . curassm •irum, 133 ·fJ .fmticosum, 132 N e/osis, 30 flemitclia, 255, 268, ·285, 286 fleuleophytwn, 25 flenriettclla jascicularis~ 192 H eptantlws, 25

Herbaceous swamp Antilles, 5 Chiapas (Mexico), 154, 163 Hemandia, 22, 36 H . sonora, 116. H erodtia, 25 H erpyza, 25 H errauia purpurea, 194-1 98 Herrera (province, Panama), 167 H eteronthera, 255H eteropteris, 35, 182 H ibiscus, 8, 15, 146 H. bifurcatus var. pilosus, 161 H. cocleanus, 199 H. costa/us, 132 H. esculentus, 177 H . sorat·ius, 189, 190 N. tiliaceus, 139, 178, 182 H idalgo (Mexico), 63, 65, 71, 96, 137,301,302, 307 H idalgoa breedlovei, 152 H ieronima, 22, 226, 239, 261, 285-288 H. alchorneoides, 261 High mountain forest, 5 Higuey (Hispaniola), 9 Hilaria, 10 Hillia, 22 Hintonia, 70 Hippocratea, 22 H . volubilis, !78, 181, 226, 241, 262,

285, 286, 287. 21:!8 Hippomune mmtcim:lla, 7, 182, 184 1-firaea reclinata, 178, 181 H!rtcl/a, 21, 35 H. americana, I 78, 180, 18 1 N . oblongifolia, 180, 181 fl. racemosa, 109, 180, 181, 194 Hispaniola (see also .Dominican Rcpubl i~.

Haiti), 1-4, 6, 7, 9, 10, 12, 14, 17, 19, 20, 21, 25-34, 36, 37 floJ!iummia, 31, 146 N. capil/aceu. 199 H. orizabeusis, I 05 1-/offinanseggia, 68 Hohenbergia, 28 Ho/acamlta, 62 Ho larctic elements (Mexican nora), 69 Ho/odiscus argemeus, 161 Homa/ium, 21 Honduras, 15, 43 Homemamtia, 25 Houstonia mbra, 133 Huatusco (Vcracru7., Mexico), I 03, 104 Climatic chart, 102 Huayacocotla (Mexico), 96 Huehuetenango (Guate~1a la), 152 Hucrtea, 26 Hura, 44, 226 H. crepitons, !96, 21 4, 241, 261 H . polyaudra, 159 Hybantlws, 23, 28 Hybo'11erma, 25 Hydrangea, 222-224, 235, 266 H. pauamensis, 266 flydrolea, 27 fl. spinosa, 190 Hygrophytic (forest type, Lesser Antilles), 5 Hylocereus polyrltizus, 183 Hymenaclme aJnplexicaulis, 163, 189 Hymenaea, 13 · H . courbaril, 158, 191 Hymeuocallis, 143 H. americana, 183,213 Hymenoclea, 68 Hyparrltenia rufa, 177, 180, 185 Hype/ate, 23, 24 Hypet·baena, 22 Hypericum, 213 Hypsithermal interval, 206, 292 Hyptis, 70, 146 H . capitata, 176 H . conferta, 132 H. /antanaefolia, 176 H. pulegoides, 184, 186 H. recurvata, 184, 186 H. aff. rugosa, 132

375 H. saPtumarwn, 176, 178 li. sutll·eolem, 176 H. ••r:rticif!{;ra, 176

lduumrlws, 36 ldria, 62

/lex, 15, 119, 233, 241, 243, 245, 256, 257, 285,286,288,290,308 I. condensata, 11 5 I . guianensis, 180, 18 1, 256 / . occidentulis, 256 /. vomitoria, 104, 306 Illicium , 26 I. floridanum, 306 /. IIICXi£"011111/1, 306 1/ysamltes inaequalis, 190

Incipient forest (Panama), 175- 177 l ndigofera, 146 I . lespedezioides, 186 I . suffruticosa, 179 fuga, 15, 109, 146, 181, 191, 198, 216 I . latibracteala, 105 I . puncta/a, 192 l . spuria, 11 5, 195 lnopltloeum amtatum, 181, 196

Intertropical Convergence Zone, 169, 170 Ipomoea, 7, 146, 213, 219, 250, 251, 260, 285 I . aquatica, 260 I . bataras, 260 I . mimttiflara, 176 l . muricara, 132 l . pes·caprae, 142, 143, 163, 182, 183, 213 I . stolonifera, 143 l resine, 146 I. celosioides, 143, 144 / .nigra, 115 l riantltera panamensis, 264 lriartea, 224,231,235,237,239,251,253,285-

288 I . cometo, 198, 235, 251 I . exorrltiza, 195, 196,251,253 I . gigantea, 251, 253 I. ventricosa, 2"53 lsclmosiplwn, 24 Iserlia, 30 I . haenkeana, 177- 179 lsidorea , 26 Isla Verde (Veracruz, Mexico), 143, 144 Isle of Pines (province, Cuba), 9, 31-33 lsocarpa, 22 .->':"~:-::-':...-____ Isthmus deTehuantepec, 1 51, 16Q,.)~ ~· ::. C,'v"---l va asperifolia, 143 / _.,· ,.. -\ lxora, 28 . ,\ ,' . ,. i; , ,

\\ \ ' . ; (, i

\~.~~3/ f f

'. '.

376

INDEX

Jacaima, 26 Jacamnda , 9, 26 J. copaia, 195, 196, 214 Jacaratia do/idwula, 109 J;~ckso n (f), 40 Jacquemontia tamnifo/ia, 184- 186 Jacquinia, 7, 21, 182 J. aw·antiaca, 143, 160 J. axillal'/·s, 126 J. ptmgens, 143 Jalapa (Veracruz, Mexico), 85, 96, 124 Jalisco (Mexico), 69, 307 Jamaica, 4, 6, 10- 14, 16, 19-21, 26- 29, 31, 32, 34, 36 Jatropha, 8, 36, 67, 146 J. pseudocurcas, 124 J ohn Crow Mountains (Jamaica), 12 Juglans, 22, 28, 301, 302, 304, 308, 309, 310 , 3 11 J. py riformis, 104, 302, 307 ) 11/tCUS, 29, 146, 163 Juniperus, 26, 69, 136 J. deppeaua, 98 J. aff.f/accida, 137 Jussiaea, 176, 190,213, 221,224, 247,249,264, 287, 288 J. /1(/((1/IS, 189, 190, 221, 247, 264 J . sujji'uticosa, 189 Justicia, 222, 224, 252, 255, 285 J . comata, 193 J . pectomlis, 176, 178, 193, 194

Kallstroemia, 146 Kalmia, 12, 30, 33 Karwittskia, 26 K. ca/deranii, 159 K. humboldtiana, 137 Kegeliella, 31 Kitchen middens Antilles, 16 Panama, 210 Klugia azureLJ, I 04 Kniglttiopltyl/um wilcoxianum (f), 42 Koeberlinia spinosa, 65, 68 Koelmeola, 25 Koltleria tubif/ora, 184, 186, 189 Koste/etzkya, 23, 29, 36 K. pentasperma, 190 K. sagillata, 190 Krameria, 27 Krugiodendron, 23 Kyllinga brevifolia, 132 K. odorala, 176 K. peruviana, 183 K. pungens, 183

La Boca (f; Oligo-Miocene, Panama), 310, 311 U trftiWIIIfw.v, 30 Laduwtaulon , 12, 30 Litci.1tema, 3 1 Laet ia, 22, 23, 29 Lit[oensia, 226, 235, 285-288 L . ptmictfolia, 158, 192, 239, 248, 263 Lagascea lteliwitltifolia, 96 Lagetttt, 29 Laguna Madre (Mexico), 272, 273 Laguna Tortuguero (Puerto Rico), 9 Laguncu/aria, 8, 35, 139, 213,283 L. 1'1/CCillU.m, 139, 143, 162, 182, 187- )89 Lake Enriq uillo (Hispaniola), 6 Lake l'ctcnxil (Guatemala), 207 La Meseta Central de Ch iapas, 152 Lantana, 1, 146, 179, 213 L. camara, 175, 177, 179, 192 L. hirta, 164 L. hispida, 96, 164 L. trifolia, 175, 177 Lantmwpsis, 26 Lllplacea, 22;-JG L. fruticosa , 198 , Larix, 303, 304 · Larrea, 65, 68 L. tridentata, 65 Las Cascadas (f; Oligo-Miocene, Pa nama), 311 Las Choapas (Veracruz, Mexico), 131 Las Villas (province, Cuba), 9, 10, 31, 32 Lasiatis, 146 Lasiantlws, 24, 36, 37 Lasiocroton, 29 Late secondary fores t (Panama), 175, 179- 181 Leaf-margin analysis, 48-50 Leaf-size analysis, 50-53 Leaf-size classes, 48 Leandro diclwtoma, 175, 177,192, 194, 197 Lebetina, 30 Lechea, 12, 30 Lecythis, 195 Leersia, 163 Leeward Islands (Lesser Antilles), 14, 19, 20 Leiphamos, 21 Lemna cyclostasa, 190 Lepecltina, 30 Lepidesmia, 30 Leptoch/oa dubio, 68 L. fi!iformia, 186 Leptogonum, 25 Lescail/ea, 25 Leucaena multicapitu/a, 224, 235, 262, 285, 287 Leucothoe mexicana , 96, 99, 306 L. populifolia, 306

IN I.) EX Leuc·oCI'oton, 29 Leucuphylhmt, 62 L. amhiguum, 65 Liabum, 22, 23, 29 L. g/almmt var. hypo/eucwn, 161 Licauia, 14, 24, II 0 L. arborea, 158, 223, 235, 265 L. hypaleuca, 109, 193 L. p/Mypus, 156, 191, 195 Licaria, 2 2 L . peckii, 109, 118, 155 Linmoclwris, 26 L. flam, 145, 191 Linaritt, 30, 146 Lindenia ril•a/is, 192 Linodera. 21, 36 Linudendron, 25 Lippia chiapensis, 16 1 L. hypo/eia, 96, 146, 164 Liquidambar, 30 I, 302, 308- 311 L. macrophyl/a, 99, 103- 105, 302, 306 L. styracif/ua, 43, 160, 306 var. nzexicmw, 307 Liquidambar forest (Veracruz, Mexico), 97, 102, 11 7, 124 Liriodendron, 30 I, 31 1 Liriosma, 223, 224, 233, 24 1, 264 L. adlwerens, 264 L. macrophyl/a, 264 Lisiamlws jefensis, 199 Litsea, 119 L. g/aucescens, 96, 307 L. neesian'ii, 161 Littoral forest (Pana ma), 175, t 82, 183 Litto ral hedge, 4 Littoral thicket , 4 Littoral woodla nd, 4 Llanos Orientales (Colombia), 206 Loasa, 30 · L. tripl!ylla, 104 Lobelia, 9, 15 L. nona, 163 Loese/ia glandulosa, 136 Loma Pela do (pla nt list ; Panama), 199 Loncltocarpus, 13, I 14, 146 L. cruentus, I ll L . guatema lensis, Ill L. pentaphy llus, 182 L. santarosanus, Il l Lopezia Jangmaniae, 152 Lophocereus, 62 Lophosoria quadripinnata, 96 Lopltotocarpus, 190 Los Cuervos (f ; Eocene, Colombia), 31 1 Los Naranjos (Veracruz, Mexico; vegetation profile), 101

377

Lo s Santos (province, Panama), 167 Lo s Tux lias (sec also Sierra de los Tuxtlas), 88, 11 8 Lower montn ne r~ i n forest (Chiapas, Mexico), 151, 153, 154,1 56- 158 Lower montn nc wet forest (Panama), t 72 Lowland formations (vegetation, Antilles), 5, 8- 12 Lowl~nd tropical rain forest (Panama), I 72 Lo w trees, shrubs (Panama), 173, 174 L udwigia, 176, 190, 193 L. helmimhorrhiza, 189, 190 L. octowtvis ssp. sessilif/ora, 189 L. peruviana , 163 Lueltea, 30, 146, 233 L. candida, 159, 183- 185 L. seemmmii, 179, 191, 192, 194, 195, 197,21 5, 226,227,239,241,26 7, 285-288 L. speciosa, 124, 177, 179 Lwwnia, 22, 23, 29 Lupimtf'"e/egans, 94 L. 11101/((111/t.\', 94 L . •·aginaltts, 94 Luquillo Mountains (Puerto Rico), 9, II , 14 Luzula racemo~·a, 163 Lycium, 67 Lycopodium, 15, 285- 288 L . cermwm, 104, 189 Lyco>uis latifolia, 179 Lycurus ph/eaides, 137 Lygodium, 146 Lyonia, 22, 23 Lysi/oma, 70 L. aurita, 159 Lyt ln·um acinifolium, 96 L . vulneraria, 163

Maba verae-crucis, 124 M abea, 239, 285, 287 M. ocddenta/is, 192, 194, 195, 197, 240, 26 1 M ac!taerium, 8, 35 M. capot e, 194 M. purpurascens, 178, 181 Maclwerocereus, 62 Maclwonia, 22 Macrocarpaea, 22, 26 Macrocnemum, 31 M. glabrescens, 194, 195 Macro/obiwn, 237 Madden Dam (Panama), 212 Mag nolia, 22, 28 M. dea/bata, 306 M. grandif/ora, 306

378

INDEX

Mognolia macrophy/la, 306 M. , ·cJriedemw, 104, 302, 306 M. ,,ftarpii, 152, 157 Maltonia pmticulata, 158 · M. vu/cania, 161 Malac!te, 147 Malacotltrix, 68 Mallmea, 24 Ma/axi.1· soulei, 96 Ma/mea depressa, Ill Malouetia, 35, 36, 223, 249 M . guatemalensis, 256 Malpighia g /abra, 214 M . pwricifolia, 126 Malvaviscus, 147, 213 M. arboreus, 164 Mammillaria, 62 M. camptotricha , 137 M. ce/ciana, 137 M. dea/bata, 137 M. elcgattr, 137 M andevilla, 31

Mandinga, Laguna de Mandinga (Veracruz, Mexico), 133, 138, 139 Manellia , 21 Manglar (swamp vegetation, Chiapas, Mexico).~ 161, 162 Mangrove, mangrove forest, swamp Antilles, 5, & Chiapas (Mexico), 151, 154, 162 Veracruz, 97, 137-139 Manicaria, 191, 192 M. saccifera, 191 Maniltot, 222, 261 M. esculenta, 175, 177, 179, 203, 239, 247, 26 1 Mani/kara ac/11·as, 155 M . clticle, 181 M appia, 22, 23 M aranta, 146 M . arundinacea, 184, 186 Marantltrum, 30 Marcgravia, 21 Margarantlws, 30 Margaritaria nobilis, 179 Marila, 26 M . macropltylla, 195 Maripa, 222, 251,. 260 M. panamensis, 194, 260 Mariscus jamaicetrsis, 190 Mar Muerto (Chiapas, Mexico), 162 Marsdenia, 22, 146 M . macrophylla, 104 M. margaritaria , 183 Marsi/ea, 190 Marsypianthus, 28

INDEX M . clwmaedrys, 186

Martinez de Ia Torre (Veracruz, Mex~o), 85, 112, 113 Martinique, 3, 4, 9 M asm gnia, 23, 29 Mason River (savanna, Jamaica), 9 Massif de Ia Hotte (Haiti), 33 Massif de .Ia Salle (Haiti), 33 Massif du Nord (Haiti), 33 Masticltodendron, 23 M. capari var. tempisque, 116 Matanzas (province, Cuba), 31, 32 M atayba , 22 M. glaberrima, 183, 185 M . oppasirifo/ia, 109 Matisia sreuopetala, 245, 258 Matorral rosetofilo, rosetulifolio, 136 Mattfeldia, 25 Matrulea lriuenia, 157 Mature forest (Panama), 173, 174 Mauritius, 16 M ayaca, 26, 35 M . aubletii, 190 Mayan-swidden agriculturalists, 152 Mayo River (Sonora, Mexico), 69 M aytenus, 67 Megalopanax, 25 Megastigma, 152 Melampadium, 146 Me/auantlms, 30 Me/am hera aspera, 182 Me/iosma, 28, 36 M.alba, 104 M. matudae, 157 Melocactus, 7 Me/ocltia, 147 M. ltirsllla, 132 M . melissifolia, 190 Meudoucia, 222, 226, 25 1, 255, 289 M. retusa, 255 Meuodora, 61 Merceuaria campecltiensis, 272 Meriauia, 22 Merremia, 223 M. discoidesperma, 143 M. ruberosa, 250, 260 Merycocltoerus, 209 Mesecltites, 26 Mesophytic (forest type, Lesser Ant illes), 5 Metopium, 23 M. toxiferum, 7 Mezquital Valley (Hidalgo, Mexico), 65, 66,71 M iconia, 15, 17, 21, 147,263 M. argentea, I ll , 178-18 1, 190, 194,215 M . borealis, 194, 197, 198 M. hyperprasina, 178

M _impel io/aris, 117 M. iusularis, 178 M. /accra, 177, 179 M. /auriformis·, 157 M. oinochrupltylkl, 197, 198 M. pteropoda, 178 M. rat•enii, 152, 158 M . triner via, 117 M icroclt/oa k unthii, 132 Microcycas, 12, 25 Microplto/is, 28 Microtea, 35 Mid-American Channel, 208 Mikania, 147 M . guaco, 115, 177, 180, 193 M. micrantlw, 171, 180 Milleria, 30 Mimosa, 67, 147 M. pigra, 126, 192 M. pucida, 132 M . pusilla, 186

Miocene floras Panama, 3 10, 311 Venezuela, 311 Veracruz, 308-311 Mirador (f; Eocene, Colombia), 311 Mirandaceltis monoica, 11 5, 11 6, 118 Misa/1/eca capitata, 116 Misant la (Veracruz, Mexico), 101 , 103, 113, 116 Mitracarpus brevif/orus, 184, 186 Mitreola,J6

Moa (Cuba), 14 Mogote (limestone cliffs), 6, 12, 13 Mohave, 64 Mollinedia guatemalemi.r, 157 Mollugo, 222, 233 M. verticil/ata, 255 Mommsenia, 25. Momordica, 147 M . clrarantia, 115, 177, 193 Mannina, 70, 119 M. xalnpense, 161 Monoclraetum f/oribtmdum, 96 Monsoon forest (Panama), 172, 175, 193-197 Montagnes du Nord Ouest (Haiti), 33 Montane, lower montane rain forest Chiapas, 151- 154, 156, 157 Panama, 172 Montane formation (vegetation, Ant illes), 5, 12-16 Montane thicket, 5, 15 Montane wet forest (Panama), 172 Montanoa ltexagona , 160 Monte (Argentina), 65-67, 71 Montric/1ardia, 15

379

M. arbores..ens, 187- 189 Montserrat (island, Ant illes), 4, II Mora ole1[era, 187, 188, 191 Morinda pilll(llllensis, 182 Morrisonia, 27 M. americana, 126 Mortonitt, 62 Morloniodendron, 109, 242 M . guaremalense, 111 Morus, 302 Mosquitoxy/ou, 31 M. j amaireme, 99, 157 Mossy forest (see also elfin) , 5, 15, 11 9 Mount Hope (Panama), 210 Mourit'i, 23 !yf. parvifo/ia, 193 Mt. Orizaba ( Mexico, see also Pico de Orizaba), 73, 75, 94 Mucuna, 147, 222, 224, 236, 263 M. bracteata, 177, 180, 192 - M. mutisiana, 182 M. s/oanei, 182 Muelt/enberkia tamnifo/ia , 164, 265 Mult/enbergia, 139 M . gigantea, 163 M. macroura, 163 M. robusta, 163 Mwrtingia, 147 M. ca/abura, 175, 177 Myrcia, 198 M . ~p/endens, 192, 194 Myrciaria /loribrmda, 180, 181 M. oneil/ii, 180, 181 Myrica, 21, 101, 232, 243, 245, 264, 285-288, 290, 301' 302, 304, 308- JII M. cerifera, 99, 119, 132, 161,306 M. mexicana, 266 M. pring/ei, 306 M. tomentosa, 182 Myriocarpa, 147 M. bifurca, 11 5 Myroxy lon balsamum, li S var. pereire, 197 Myrtillocactus, 62, 152 M. geometrizans, 137

Najas guada/upensis, 145 Nama, 22 N. spinosa, 190 N. undu/atum, 68 Naolinco, 116 Narva/ina, 30

Nassau, 3 Nautilocalyx, 24

Nautla (Veracruz, Mexico), 97, 121

380

Nectandra, 44, 185 N. coriacea, 142, 143 N. gent/ei, 171 N. globosa, 191 N. reticulata, 151 N. salicifo/ia, 11 8 N. sanguinea, 115 N. sbumta, 156 Neea, 22 N. amplifolia, 194 N. /aetMrens, 194 Ne/umbo, 36 Nemastylis temtis, 132 Neobracea, 27 Neobuchia , 25 Neomacfadya, 30 Neomazea, 26 Neoregnellia, 26 Neothymopsis, 27 Nephelea mexicana, 99, 104, 117 Nephrolepis biserraw, 189 Nepsera, 15, 25 Nerium o/eandet·, 143 Neurolaena, 22, 23, 29, 147 N. Iobato, 115, 177, 179, 192 Nicoticma, 67 Nodocarpeo, 25 No/ina, 70, 135, 136 N. parvi/fora, 91, 136 Napa/eo, 123, 137 N. cochenil/ifera, 126 N. dejecta, 124 Norantea, 24 Nortes (cool, wet periods), 84 Northern highla nds (Chiapas, Mexico), 149, 150, 153, 156, 158, 160

Notholaeua, 61 N. Ol/1'1!0, 68 N. sinuata, 137 Notoptera, 31 Nuclear Central America, 208 Nueva Galicia (Mexico), 69, 11 7 Nuevo Leon (Mexico), 307, 308

Nuphar, 9 Nymphaea, 9, 190 N. amp/a, 145, 190 N. blanda, 145, 191 Nymphoides, 23 N. humboldtiana, 190 Nyssa, 55, 56, 301, 304, 310, 311 N. sy/vatica, 160, 306

Oak forest (Veracruz, Mexico), 97, 99, 101 , 102, 119, 124, 130 Soil profile, 101

INDEX

IND EX

OaKaca (Mexico), 66, 69, 7 1, 11 6, 301, 307 Oaxacania, 66 Ochroma, 147,215, 226,233,246, 247, 258, 285-287, 289 0. limonensis, 179 0. pyramidale, 171, 179, 258 Ocimum nricnmthum, 176, 178 Ocotea, 15, 21, 44 0 . rubraf/ora, 156 0. r11brittervis, 180, 181 0. veraguensis, 118 Odoll/ocarya nitida, 183 Odontonema longifolirmt, 193 O. strict11m, 192

Oryctautlw.\· £'111'llrfoliu.\·, 233, 263, 285, 287 Oryza sotil•a. 176 Osmwrt!rus americauus, 306 Ossaea, 21 , 22 Ostrylt, 304 0. guatemaleusis, 161 0. virginiana, 105, 306 Othake lindenii, 143 01/osc/rmidtia, 27 Ollosclrulzia, 28 Ouratea: 22, 198, 290 0. cocleensis, 199 O. guatema/ensis, 180, 181,226,243 ,247, 264, 285, 286, 288

Oecopetal11m mexican11m, 151 Oenocarpus, 183 0. pmtamensis, 191, 198 Oenothera, 30 0. drummondii, 142, 143 Okenia hypogaea , 124, 143

0 . /uceus, 180, 181, 194, 197, 198 Oxa/is, 132, 147 0 . comiculaw, 96 0. decapltylla, 96 Oxaudra, 13, 22 Oxylobus arbutifolius, 94 Oxypetaltml, 22

Old forest (Panama), 173, 174

0/eiocarfJ0/1 panameme, 196,197 0/igomeris, 67 Oligo-Miocene floras Cucaracha (Panama), 310 Culebra (Panama), 310, 31 1 La Boca (Panama), 31 0, 311 Las Cascadas (Panama), 3 11 Simojovel (Mexico), 310, 311 0/media aspera, 18 1, 192, 215 0/medie/la betschleriana, 105, 157 0/neya, 62 01)'1'0, 147 0 . /atifolia, 132 Omp!ra/ea, 29, 34 0. diandra, 182, 183 0. panamensis, 182 Oocarpon, 22, 23, 29 Operculina tuberosa, 260 Ophioglossum , 132 Oplismenus burmatwii, 176, 184-186 Opuntia, 8, 70, 137 0. dillenii, 143 0. elatior, 183 0 . pubemla, 124 Oreopanax, 15,27

0 . capita/us, 151 0. g11atemalensis, 157 0 . liebmanni, 104, 157 0. sanderianus, 157 0. xa/apense, 11 9, 157 Oriente (province, Cuba), 14, 31-33 Orizaba (Mexico), 95, 105, 132 Ormosia, 14, 28 0. ist!rmensis, 109, I ll Orthi011 subsessile, 155

Paclrira, 285- 288 P. aquatica, 139, 162, 188, 190-192,243 , 245, 258

Pocltyanthus, 26 Pacltycormus, 62

·I·I !

Pacific Coastal Plain (Mexico), 149-151, 153, 160, 162, 163 Pacourina, 26, 260 P. edulis, 241, 253, 259, 285, 287 Padiua variegaw, 144 Paepa/antlrus, 26, 35 Pa/afoxia texaua, 143 Pa/icourea, 157 P. galeolliana, 105, 119, 147 P. guianensis, 192, 194, 198 P. triplty/la, 192, 194 Palmar (palm forest), 162 Palm fores t (C hiapas, Mexico), 15 1-154, 162 Panama Climates, 169, 170, 211- 212 Ko ppen macroclima tes, 171, 172 Climatic change, 228-247 Ho ldridge life zones, 172 Map, 173 Late Quaternary and Recent (geologic) history, 209- 21 1 Late Quaternary and Recent (vegetational) history, 233-247 35,500 B.P., 233-235 11,300-9,600 B.P., 235-237 9,600-7,300 , 239-24 1 7,300-4,200 , 241-245 4,20 0- Present, 245- 247

381

Man (innucncc on vegetation), 170, 173, 174, 247 Maps Climatic, 171 Eleva tions, 168 Phytophysiognomic, 174 Political, 167 Modern pollen rain, 225-228 Physiography, 167-169, 211 Pollen d iagrams, 219-224, 285-289 Pre-Quaternary history Cucaracha (Oligo-Miooene), 310,311 Cu lebra (Oligo-Miocene), 310, 311 Gatun.(Mioccne), 310,3 11 Gatuncillo (Eocene), 310, 3 11 La Boca (Oligo-M iocene), 310, 311 Las Cascadas (Oligo-Miocene), 31 1 Present vegetation, 167-201,212- 216 Province, 167, 169 Sea-level changes, 268-293 Soils, 170 Vegetation maps, 171, 174 Vegetation types, plant commu nities, 167201, 2 12- 216 _ Brackish riparian forest, 175 , 189 Brack ish swamp forest, 175, 187, 188 Cloud forest, 175, 198, 199 Coastal beaches and swamps, 213 Deciduous seasonal forest, 175, 184, 185 Early secondary forest, 175, 177- 179 E lfin forest, 175, 199 Evergreen seasonal forest, 175, 197 F reshwater marsh, 175, 189, 190 Freshwater ri parian fores t, 175, 192, 193 Freshwater swamp forest, 175, 190192 Highlands, 213 Incipient forest, 175-177 1nland pond, river, lake areas, 2 13 Late secondary forest, 175, 179-181 Littoral forest, 175, 182, 183 Lowlands, 213,214 Monsoon forest, 175, 193- 197 Premontane rain forest, 175, 197, 198 Saltwater riparian forest, 175, 187 Saltwater swamp forest, 175, 187 Savanna, 175, 185, 186 Sub-alpine, 213 T horn forest, 175, 183, 184 Panama spur, 208, 209 Pancratium lillorale, 182, 183 Pandanus, 143 Panicun1, 17, 147 P. maximum, 176, 178, 180, 185, 19 1, 192

II 382

Panicum mo/le, 184, 186 P. pi/m·um, 176, 178 P. repens, 143 P. mdgei, 176 Panuco (Mexico), 125 Papaloapan River (Mexico ), 69 Papamla de O larte (Veracruz, Mexico), 113 Paraiso (Pana ma ; pla nt list), 196 Paraje Solo format ion (f; Miocene, Mexico), 308-3 11 Paramo, 5, 15, 94, 139,205,207 Chiapas (Mexico), t54, 163 · Veracruz (Mexico; soil profile), 140, 141 Paraino de 'Palacio (Colombia), 205 J>aramos de A ltu ra, 163 Pamtlteria, 26 Parmhe.>i.1·, 28, 30 P. breed/01•ei, 152 P. chiapensis, 161 P. microcalyx, 157 P. serrulata, 96 Parkinsonia, 35 P. actt!eata, 126 Parmentiera edulis, 124 Parthenium, 62, 147 Paspalum, 17, 147, 163 P. clavu/iferum, 186 P. ntulticaule, 176 P. pertinatnm, 99 P. p/icaut!um, 99, 176, 178, 180 P. vaginatwn, 143 P. virgatum, 176, 178, 180 Passiflara, 9, 147, 213 P. viti/alia, 194, 197, 198 Paullinia, 35, 2 26, 241, 266, 285, 286, 287, 288

Paurotis, 131 P. wrightii, 127, 129, 132 Pavonia paniculata, I 64 P. scabra, 188 P. spica/a, 188 Pectis, 7 P. elongata, 184, 186 Pedilanthus, 35, 70 Pedinopeta/um, 25 Peganum, 67 Pe/liceira rhizopltorae, !87 Pe/tostigma, 26 Penelopeia, 25 Penstemon, 70 P. genitanoides, 94 Pentac/ethra macro/oba, 191 , 192, 195 Pentagonia, 197 P. bl'acltyotis, I 97, 198 P. macrophyl/a, 197, !98 Pentarrhaphis scabra, 186 Peperomia, 11, 34, 213,215

IN DEX

P. deppeana, 104 P. Jdabel/a, I04 J>. obtusifo/ia, 104 J>. pellucida, 184 Pera, 26 P. arborea, 180, 181, 196 Peratantlte, 25 Pereskia, 30 Pcrlas Archipelago, 256

Pemellya tomasii, 163 Perote (Pucbla, Mexico; see o/so Cofre de Perote, Va lley of Perote), 88, 97, 98, 133, 134, 135 Perrottetia , 147 P. /ongistylis, 104, 11 5 Pcrsea americana, 307 P. cltamissonis, 307 P. cinerascens, I 04, 307 P. tlonne/1-smitltii, 157 P. scltiedeana, 118, 157, 198, 307 Peru , 66, 67 Pcten region (G uatemala), 153 Petiveria, 147 Petrea, 24 Plweosp!taerion, 22, 28 Phaseo/us, 147 P. adenantltus, 182 P. /ongipetlunwlatus, 176, 184, 186 P. steuo/obus, 186 Phenax mexicanus, 161 Phialcmthus, 23 Phidiasia, 25 Pltilotlendrou, 15, 43, 44 P. er/ansouii, 178, 181, 195

P. gigauteum, II P. guatemalense, 181 P. guttiferum, 194 P. !tarlowii, 195 Pltiloxeris vermicularis, 182, I 83, 187 Pltinaea, 26 Phoebe acuminatissima, 104 P. gentlei, 105 P. jolmstonii, 177, 180, 181 P. mexicana, 116 Pltotinia matudai, 157 Pltragmites com!llllllis, 163, 189 P!tryganocydia corymbosa, 177- 181, 193 Pity/a, 147 P. nodi/fora, 143 P!tyllacanthus, 25 Pltyllanthus, 7, 8, 17,261, 285,287,288 P. acwninatus, 239, 261 P. brasiliensis, 215 P. carolinensis, 186 P. diffusus, 184, 186, 190 P. gmndifolius, 124

j .i

·I

P. micrandrus, 126 P. nimri, 189 P. nobilis, 124 P. stipu/atus, 184, 186, !90 P. urinaria, !76 Pltyllomelia, 25 Pltylostylon, 7, 22, 23, 26, 29 PltJ•.wlis, 147 Pltytelepltas, 197, 422, 231, 235, 253, 286, 287 P. seematmii, 192 Pltytolacca, 147 Piaropus azureus, 189, 190 Picardea, 26 Picea, 301, 303, 304, 308-3 11 P. cftilwalmana, 308 P. mexicana, 308 P. mbens, 304 Pico de Orizaba (Mexico; see also Mt. Orizaba), 86, I 40, 142

Picranwia, 22, 147 P. amidesma, Il l, 198 P. dwyeri, 198 P. telrmnera, Ill Picrasma, 30 Picrodendron, 29 Pictctia, 8 Pieri.1·, 12, 30, 33 Pi/eo, 17, 34, 147 P. pubescens, 118 Pilocarpus, 28 Pimento dioica, I l l , 117 Pinar d el Rio (p rovince, Cuba), 9, 12, 31-33 Pinares and Encinares, 161 Pine-oak forest (Chiapas, Mexico), 151, 152, 154, 161 , 163 Pine-oak-Liquidambar fo rest (Chiapas, Mexico), 151-154, 160, 16 1, 163 Pinguicula caudata, 96 Pinillosa, 26 Pinosia, 25 Pill/IS, 14, 26, 28, 55, 56, 101 P. ayacahuite, 99, 157 P. banksiana, 303, 304 P. cembroides, 97, 98 P. cltiapensis, 161 P. har/wegii, 86, 94, 306 P. /eiopltylla, 99 P. micltoacana, 161 P. momezumae, 94, 99, 161, 306 P. oocarpa, 15, 99, 161 P. patula, 99 P.pseudostrobus, 95, 96, 161, 306 P. rudis, 96, 306 P. strobus, 91, 306 var. cltiapensis, 97-99, 306 P. teocote, 96, 306

383

Piper, 17, 18, 147,2 13, 265 P. adtmcum, 175, 177, 179 P. auritum, 179, 215 P. darieneme, 194, 197, !98 P. nwrginatum, 177, 179. I 98 P. mi;·amlem·e, 115 P. nitidwn, 139 P. pinoganense, 194 P. retimlatum, 194, 198 P. sanctum, !58 Piperantltera, 25 • Piptadettia /fava, 160 Piptocm11a, 3 I Piptocoma, 2-7 Piranopappus roseus, 132 Piriqucta, 3 5 Piscidia, 8 P. piscipu/a, 123, 160 Pisonia, 147 P. aculeata, 184 Pistia, 213 P. stratiotcs, 145, 189, 190 Pitcaimca, 15 , 36 Pithecellol!imn, 8, 12-14, 126, 147 -p, arborewn, Ill , l 17, 156 P. ra/ostachys, 124 P. di.rcifemm, 139 P. dulce, !60 P. erytltrocarpmn, 124, 139 P. /fexicaule, 137 P. imigne, 115 P. kmceolatum, 129 P. lmrgtfolitmt, 192, 196 P. recortlii, 129 P. mfesrens, 178, 180, 192, 194 P.

S0/11011,

!84, 191

P. vah/ianum, 196 P. vulcanorttm, 105 Pityrogramma calome/anos, 189 Plantago niveo, 133 Platanus, 304 P. chiapensis, 157, 162, 307 P. /indeniana, 307 P/atymiscium dimorphandrum, I 58 P. pinnatum, 184 P. po/ystachyum, 184 P. yucatanum, 115 Platypodium e/egans, 193, 196 P. maxonianum, 196, 2 14 P/eodendron, 27 Plethadenia, 26 Pleurantlrodendron, 147 P. mexiCilnum, I I I, 117, 126 Pleurothallis, 17, 18 Plocosperma, 152 .Piuchea purpurascens, 190

384

INDEX IN DEX

Plflmhaf!O, 126 Plflmeria acutifa/ia, 124, 143 P. rubra, 182, 183, 187 Podocmpus, 22, 36, 41, 44, 46, I0 I, 233, 23 7, 255,268,285-288 P. guatemalensis, 110, 199 var. pinetonmr, 109 P. matudai, 104 Pogonopus .1peciosu.\', 197, 198 Poitaea, 25 Pollen analysis, Panama Climatic change, 228-247 Gatun Basin diagrams, 222- 224, 285-288 General discussion, 2 19-221 Identification, nomenclature (fossil polle n) 229-23 1 Modern pollen rain, 225-228 Vegetational history, 233- 247 Polyga/a, 132, 147, 213 P. an·. adenoplrora, 132 P. bryzoides, 186 P.jefensis, 199 P. /ongicau/is, 184, 186 P. panicu/aw, 176 P. wurdackimra, 199 Polygommr, 9, 213, 233, 243, 247, 260, 265. 285-288 P. acrmrinatum, 260 P. (JI/1/C((I(JI/11, 190, 265 Polyumia maculata, 164 Polypodium kulmii, 184 Polypremum, 30 Pontederia, 213, 255 P. cordata, 190 P. /ancifo/ia, 145 P. sagitalla, 138, 145 Papal (herbaceous swamp), 163 Popales, popoay (Thalia swamps, Veracruz, Mexico), 138 Populus, 69, 301, 308- 311 P. mexicana, 307 Por/ieria, 68 Porophyl/um, 147 P. rudera/e, 176, 178 Portlandia, 22 Portulaca, 1, P. oleracea, 176, 233, 265 Posoqueria /atifolia, 109, 187, 188, 191, 194, 197, 198 . Potentilla, 9 P. heterosepala, 163 P. riclrardii, 94, 307 Potltomorphe peltata, 175, 177, 180 Poulsenia armata, Ill, 118, 155, 181, 196 Pourouma scobina, 197, 198 Pouteria, 14, 28

P. cttmtreclriana, 109, 181 P. durlmulii, 143 1'. stipitala, I ~5 Poza Rica (Veracruz, Mexico), 101, 115 Premontane rain forest(Panama), 175, 197,198 Presloea montana, 11, 14 Pre;·Jonia, 24 Pl'ingleoclrloa, 66 Pl'ioria, 31, 226 P. copai[era, 170, 188, 190- 192, 196, 214, 227, 237 Pristimeria, 30 Pril'a, 36 P. /appu/acea, 178, 180, 193 Prockia, 28 Proserpinaca, 30 Prosopis, 6, 65, 183 P. chilensis, 184 P.juli/fora, 137, 183, 184 ProJium, 26, 36, 181, 196, 2 16 P. copt{l, 115, 11 7 P. mc/eodii, 178, 180, 18 1 P. panamense, 194 P. tenuifo/ium, 177, 180 ssp. mcleodii, 181 Prow·Jia, 28 Prunus brachybolrya, 105, 307 P. capu/i, 307 P. rlttmmoidcs, 307 P. samytloides, 307 P. serolina, 302 subsp. capuli, 307. subsp. serotina, 306 P. tetrademia, 104, 307 Pseudohombax, 226, 227, 243, 285, 286, 287 P. el/ipticum, 159 _ P. septenallrm, 191 , 193, 258 Pseudocarpidium, 26 Pseudocentrum, 31 Pseudoe/epltantopus spica/us, 176, 178 Pseudo/media, 22 P. oxyphyllaria, I09, Ill P. spuria, 156 Pseudosamanea guachapele, 184 Psidium, 14, 147 P. guajava, 121, 132, 177, 179, 185 P. guineense, 183 P. mol/e, 132 P. oers/edeanum, 186 P. saluJare, 186 Psillacanthus, 31 Psychotria, 8, 15, 17, 34, Ill , 147, 157, 197,215 P. ropilata, 194, 197, 198 P. erylhrocarpa, 159 P. grandicarpa, 199 P. horizon/a/is, 192

P. im•o/ucmta, 198 P. llutOII>', 142, 143

P. algae, 199 P. piJ/recobia , 198, 199 P. triclro/Oma, 104 P. va/eria11a, 198 Pterichis, 31 Pteridium, 15 P. aqui/inum, 96, 102 Pterocarpus, 8, 223, 224 P. /wyesii, Ill, 190 ('.officina/is, 188, 190- 192, 214 237, 243, 263, 285 Plerocissns, 25 Pterolepis, 24 P. pumi/a, 176, 184, 186 Pueb1a (Mexico), 66, 71, 88, 98, 132, 134, 135, 301 , 302 Puente Henriquez (Veracruz, Mexico), 98 Puente Nacional, 121 Puerto Armucllcs (Panama), 2 10 Puerto Rican Trench, I Puerto Rico, 3, 4, 6, 11- 14, 19, 20, 21, 24, 2629, 31 , 32, 34 Punta Maisi (Cuba), 7 Purdiaea, 30 ~ Puryear (f), 40, 52

Quararibea, 27, 19 1,226,245, 258, 2R5, 286, 287-289 Q. as/ero/epis, 191, 194, 195 Q. bracleolo.m , 191, 194 Q. do/iclropoda, 199 Q./unehris, Il l , 156 Q. p/erocalyx, 191 Quassia, 35, 36, 222, 224, 237 Q. amara, 194, 197, 198, 267 Quercus, 12, 30, 33, ~9. 101-104, 199, 304, 307-309 Q. acatenage11sis, 157, 161 Q. affinis, I04 Q. condicans, 96, 161, 307 Q. COS/{11/CO, 96, 307 Q. copeyensis, 198 Q. cormgata, 105, 118, 161 Q. crassi/olia, 96, 161, 307 Q. eduardi, 137 Q. excelsa, 99 Q. aff. gracilior, 118 Q. mexicana, 96, 307 Q. microphylla, 98 Q. ocoteafolia, 104 Q. o/eoides, 100-102, 110, 156, 307 Q. oororpa, 161 Q. ovandei!Sis, 151

385

Q. (1/IX/O{en.l'i.l', 151 Q. pcdunculari.r, !_32, 157 Q. pilariu.l', 105 Q. po/ymorplw, 161 Q. rugosa, 161 Q ..wputaefolia, 161 Q. ,\'CKO 1•icmis, 16 1 Q. skinneri, 104, 118, 156, 161 Q. xa/apensis, 96, 307 Queretaro (Mexico), 66 Quiina, 27 Rachicallis, 1, 22 Ra in forest D ry, 4 Lower montane, 5 Montane (cloud forest), 5 Randia, 1, 67, 126, 137, 223, 224,253, 266 R. acu/eata, 124, 129, 139, 142, 143, 160 R. albonervia, 124 R. armata, 194 R. laetel•iren.l·, 143, 144 Rangia cuniala, 272 Ranwrculus, 22, 23, 29 R. diclrotomus, 96 R. hookeri, 132 Rapanea juergenl'enii, 11 9, 158 R. myricoides, 96 Raphia, 2 14 R. taedigera, 189, 190, 192 Rauvof/ia, 8, 147, 241, 249, 256, 285, 286, 287 Ra••erria, 22 Reinhardtiagracilis, Il l Relbrmium hypocarpium, 96 Renea/mia, 35 R. cemua, 177, 180, 191, 192, 194, 197, 198 Re)'IIOsia, 1, 24 Rhabadade11ia bif/ora, 139 R. pa/udosa, 188 Rftamnidium, 27 Rhamtws betulifolia, 306 R. capraefo/ia, 307 R. caroliniana, 302 R. discolor, 164 R. microphylla, 307 R. nelsonii, 164 Rheedia, 35 R. edulis, 109 Rftexia, 28 Rftipocepftalus phoenix, 144 Rhipsalis, 36 Rhizophora, 8, 139, 188, 206, 213, 221, 223, 224,226, 233,235,239, 241, 243, 249,251, 265, 283-291 R. brevistyla, 187, 188

392 Medium semi-ever green, liS Low selvas: Low deciduous, 121- 124 Low evergreen, 119 Low semi-everg reen, 119- 121 Low thorn, 124-126, 137 Swamp, 90, 93, 137- 139 Inland, 137, 138 Mangrove , 138, 139 Veraguas (province, Panama), 167, 169 Verbena canescens, 133 V. ('(lrolina, 104 V. ciliata, 133 V. teucrifolia, 132 Verbesina, 147 V. olil'(ICCl/, 143 V. pcrymenioides, 161 Verheullia, 26 Vemonia, 147 V. canescens, 115, 177 V. deppeana, 96 V. leiocarpa, 164 V. patens, 115, 177, 307 Viburnum , 27, 37 V. acllli[olium , 307 V. lwr/lllegii, 161 V.jucundu m, 161 V.lautum , 164 V. microcarpum, 307 V. microphyllum, 307 v. monta/111111, 119 V. tiliaifolium, 104, 307 Vicia, 9 Victorino, 1, 26 Vigna luteola, 182, 183 V. repens, 183 V. vexillata, 189 Viguiera, 10 Vinales (Cuba), 12 Viola, 9, 30, 196 V. guatemalensis, 118 V. nOll/lei, 163 Virgin Islands, 19, 20 Virola, 195, 234, 235, 264, 285, 286, 287, 288 V. elongata, 264 V. guatemalensis, 264 V. kosclmyi, 264 V. nobilis, 264 V. panamensis, 196, 214 V. ·sebi/era, 196, 264 Viscainoa, 62 Vismia, 147, 179, 192 V. baccifera, !17, 179 V. /atifolia, 177, 179,215 Vitex cymbosa, 193 V. masoniana, 193

INDEX Vochy.,ia, 224, 239, 268 V. lwndurem is, 109, Ill, 155 V. jefensis, 199 Volcan de Chiriqui ( Panama), 211, 213 Volcano of San Martin (Mexico), 118, 11 9 Volcan Tacana (Mexico), 151, 163 Voyria, 35

Wall£•nia, 20, 24 Wa/tlll!ria americmw , 184- 186 W. brevitJCS, I 02 W. indica, 116, 178, 184-1S6 Warszcwicizia coccinea, 192, 195, 197, 198 Websteria, 25 Wedelin trilobnta, 182 Weinmmmia, 15, 22, 205, 213 W. pimW/a, 104, 157, 198 We/denio candida, 163 Wemeria nubigena, 163 Wigandia, 26 _ Wilcox (f; Eocene, Gulf Coastal U.S.), 39, 40, 55,301,31 1 Wimmeria acuminata, 152 W. bartlettii, 156 W. chiapensis, 158 Windward Islands (Lesser Antilles), 19 Wissadula, 147 Willmacki a, 24 Woeh/eria, 25 Wuffiabac cata, 175, 177, 180, 193,194 Wunsclmumnia. 25

X(mtlwceplwlum, 70 Xalllhosoma, 147 Xerophyti c (forest type, Lesser Antilles), 5 Xilitla (Mexico), 302 Ximwia, 8, 22, 36 X. americana , 182 Xiphidium caeruleum, 18 1, 194, 197, 198 Xylopia, 27, 185, 192 X. aromatica, 185, 194 X. bocatorena, 194 X.frutesce ns, 109, 178, 180, 181, 184, 185, 194, 198 Xylosma, 36 X.jfexuos um, 102, 104 X. panamensis, 182, 183 X. quichense, I 05 Xyris, 9 X. ambigua, 132

Yuca {Manihot ), 261 Yucatan, Yucatan Peninsula (Mexico), 2, 152

INDEX Yucca, 62 Y. treculeana, 137

Zacatcpec (Mexico), 135 Zacatonal (bunch grassland) , 163 Zaluzania, 62 Zamia, 22 Z.fw}itrac ea, 143 Z. loddigesii, 99 · Zanthoxyl um, 13, 181, 192, 196,2 16,266, 285 Z. belizense, I l l Z. caribaenu m, 129, 307 Z. eleganth·simum, 307 Z.fagara, 124, 137 Z. kel/ermanii, 104, 307 Z. limnocello, 226 Z. fJOJili/IW/ISe, 177, 179, 196, 214,226,2 27, 237, 239, 266, 285-287, 288

Z. fl/'OC'ei'IIIJI, 307 Z ..retulosum , 177, 179, 226, 227, 23 7, 266, 285, 286 Zea, 203, 286 Z. 1112ys, 175, 251 Zexmeuia aw·cw, 132 Zinnia, 70 Zinowiewia imegerrim a, 101 Z. matud~1i, 151 Zambia, 25 Zona ;irida h idalgucns e, poblana, 136 Zontmtlms , 25 Ztjmia, 147 Z. diphyl/a, 186 Zue/ania, 23, 27: 29 Z. guidonia, 102, 109, Il l , 115,1 17, 124, 156, 178, 181 Zyzyp/111.\' .wmorensis, 126

393