Agaricus of North America Review by NYBG Press

of NORTH AMERICA

Agaricus of North America is the result of 45 years of work by Richard W. Kerrigan. This volume will serve as an authoritative yet accessible sourcebook for the specialist and interested amateur alike. Filled with nearly 300 color images to help identify 180+ species, Kerrigan provides “how” and “why” explanations with technical details in a simple layout that offers clear descriptions and notable features for each species treated. Kerrigan’s unique perspective combines an evaluation of Agaricus diversity in natural ecosystems, supported by modern and historical collections, with technical descriptions either from his own notes or from herbarium collections. According to Kerrigan, “…this presentation bridges a gap between the typical specialist literature and the typical field guide, in a way that will interest many readers.”

AGARICUS of NORTH AMERICA

AGARICUS

AGARICUS of NORTH AMERICA R IC HA R D W. K E R R IGA N

R IC HA R D W. KE R R I GAN

NYBG P RE SS.O R G

MEM 114

Agaricus of North America

Richard W. Kerrigan

Memoirs of The New York Botanical Garden,Volume 114

Bronx, New York, USA

Table of Contents Acknowledgments

xiii

Why This Book? Why Now? The author’s foreword

xvii

Agaricus in the World

Agaricus in Commerce

The Genus Agaricus: History and Nomenclature

The Literature of Agaricus: The State of Knowledge

To Study and Identify Agaricus What Is the Objective? Study and Identification Macroscopic Features Microscopic Features Ecological and Geograph ical Attributes Biochemical Characters Other Modern Characters Cultural Characters Summary

17 17 21 21 32 41 41 47 49 49

Further Notes on Formats and Conventions Used in This Book

“To eat wild mushrooms . . .” Special Note on Edibility and Responsibility

Note on Phylogenetic Analysis

Sequences Representing Sections (Also Subsections and Unnamed Major Lineages) of Agaricus in the Phylogenetic Trees

Typification of Published Taxa Agaricus abruptibulbus, A. agrinferus, A. amicosus, A. andrewii, A. campestris, A. crocodilinus, A. cuniculicola, A. haemorrhoidarius var. fumosus, A. variabilis, Polyplocium californicum

Keys to Agaricus of North America I. Dichotomous Key for the Placement of Agaricoid and Secotioid Specimens of Agaricus Subgenus Agaricus in North America to Sections or Groups II. Quasi-Synoptic Key for the Placement of Specimens of Agaricus Subgenus Agaricus in North America to Sections or Groups

Agaricus [Subgenus Agaricus] Agaricus Section Bivelares Agaricus Subsection Hortenses A. bisporus var. bisporus A. bisporus var. burnettii A. sipapuensis sp. nov. A. agrinferus A. subfloccosus

62 65 69 70 74 76 78 80 82

T able of C onte nt s A. devoniensis subsp. devoniensis A. devoniensis subsp. bridghamii A. bitorquis A. subsubensis A. sp. ‘RWK 1789’ A. subperonatus Agaricus Subsection Cupressorum A. cupressophilus A. tlaxcalensis Other Entities in Section Bivelares A. villaticus Brondeau sensu Isaacs A. ‘brevistipus’ (Isaacs nom. prov.) A. sterlingii A. brunnescens

84 86 88 90 92 94 96 98 100 102 102 102 102

Agaricus Section Chitonioides A. bernardi A. pilosporus A. vinaceovirens A. gennadii A. bernardiformis A. pequinii A. sp. ‘the Palmer collection’ A. sp. ‘GQ-3’

105 108 110 112 114 116 118 120 122

Agaricus Section Xanthodermatei Agaricus Subsection Xanthodermatei A. xanthodermus A. malangelus sp. nov. A. californicus A. arizonicus sp. nov. A. placomyces A. approximans A. cf. approximans A. hybrid ‘RWK 2023’ A. berryessae sp. nov. A. deardorffensis sp. nov. A. leptocaulis sp. nov. A. iodosmus A. endoxanthus A. pocillator A. tollocanensis A. sp. ‘RWK 1007’ [Group linked to A. pseudopratensis] A. buckmacadooi sp. nov. A. kriegeri sp. nov. Agaricus Subsection Hondenses subsect. nov. A. hondensis A. subrufescentoides

123 127 132 134 136 138 140 144 146 150 152 154 156 158 160 162 164 166 168 170 172 174 176

vii

viii

T able of C onte nt s Other Entities in Section Xanthodermatei A. glaber A. cervinifolius A. “praeclaresquamosus”: Concepts from Western North America A. sp. ‘RWK 741’ A. sp. ‘RWK 2125’ A. ‘crassistipus’ (Isaacs nom. prov.) Excluded Taxa A. placomyces var. microsporus A. placomyces var. flavescens Agaricus Section Sanguinolenti Agaricus Subsection Sylvatici A. rubronanus A. sp. ‘RWK 2013’ A. sp. ‘RWK 1335’ A. bivelatoides; A. collection RWK 1171 A. benesii sensu lato A. cf. benesii A. sylvaticus subsp. occidentalis subsp. nov. A. sylvaticus subsp. cf. occidentalis: California Variant A. cordillerensis sp. nov. A. hupohanae sp. nov. A. thujae sp. nov. [Possibly affi liated species] A. arorae A. sp. ‘RWK 1208’ Other Entities in Subsection Sylvatici A. albosanguineus A. haemorrhoidarius sensu Peck A. haemorrhoidarius var. fumosus A. collection Pg 317 #20 A. haemorrhoidarius sensu Murrill A. haemorrhoidarius sensu Smith A. sylvaticus sensu Hesler A. sylvaticus sensu Atkinson A. sp.: West Virginia collections Agaricus Subsection Bohusia A. brunneofibrillosus sp. nov. A. amicosus Agaricus Section Nigrobrunnescentes Agaricus Subsection Nigrobrunnescentes stat. nov. A. eludens (provisional placement) Agaricus Subsection Pattersonia subsect. nov. A. pattersoniae A. fuscovelatus A. sp. ‘RWK 1583’ A. lilaceps

178 178 180 181 181 182 183 183 183 185 188 192 194 196 198 200 202 204 206 208 210 212 214 216 218 219 219 221 223 223 223 224 224 226 228 230 233 234 236 238 242 244 246 248

T able of C onte nt s A. laparrae sp. nov. A. sp. ‘A.G.’

250 252

Other ‘sanguinolent’ Lineages: The ‘tennesseensis’ and ‘TRc’ Lineages A. tennesseensis sp. nov. A. sp. ‘ASM 13217’ A. sp. ‘NY 49276’

253 256 258 260

Agaricus Section Agaricus [Main lineage] A. cf. campestris A. gastronevadensis sp. nov. A. andrewii A. argenteus subsp. argenteus A. argenteus subsp. annetteae subsp. nov. A. pampeanus (A. solidipes Peck 1904, nom. illeg.) A. aristocratus A. incultorum sp. nov. A. sp. ‘RWK 807’ A. porphyrocephalus var. porphyrocephalus A. porphyrocephalus var. pallidus var. nov. A. moellerianus A. cf. altipes A. griseicephalus sp. nov. A. cf. cappellii A. cf. chionodermus A. sequoiae [Basal lineage(s)] A. rubribrunnescens A. erindalensis sp. nov. A. depauperatus A. argyropotamicus Other Entities in Section Agaricus A. projectellus A. praerimosus A. spp. ‘RWK 1923’ and ‘PBM 2580’ A. ‘pinyonensis’ (Isaacs nom. prov.)

263 270 272 274 278 280 282 284 286 288 290 292 294 296 298 300 302 304 306 308 310 312 314 314 318 319

Agaricus Section Spissicaules A. cf. litoralis A. bellanniae sp. nov. Other Entities Possibly in Section Spissicaules A. sp. ‘Isaacs 1298’ (as A. annae) A. placomyces var. microsporus

321 326 328

Agaricus Section Subrutilescentes sect. nov. A. subrutilescens A. vinosobrunneofumidus sp. nov. A. thiersii sp. nov.

333 336 338 340

330 331

T able of C onte nt s Other Entities in Section Subrutilescentes A. collection RWK 1320

342

Agaricus Section Rarolentes sect. nov. A. butyreburneus sp. nov.

343 346

Agaricus Section Minores A. comtulus A. micromegethus A. kerriganii (A. semotus sensu auct.) A. diminutivus A. comptuloides A. auricolor Krieger (nom. illeg.) A. sp. ‘RWK 2014’ A. stevensii sp. nov. Other Entities in Section Minores A. collection RWK 916 A. collection RWK 652 A. citrinidiscus A. collection RWK 1322 A. comtuliformis A. cylindriceps var. aureus A. sulphureiceps A. collection WRWV05-440 A. collection RWK 2022 A. sp. ‘RWK 2282’ A. sp. ‘CA636’ A. sp. ‘RWK 2118’ A. placomyces var. flavescens A. friesianus Taxon of Uncertain Placement A. placomyces var. microsporus

349 354 356 358 360 362 364 366 368

Agaricus Section Arvenses [The pigmented sylvan group] A. augustus A. nanaugustus sp. nov. A. julius sp. nov. A. perobscurus A. subrufescens A. flavitingens A. smithii A. cuniculicola A. rhoadsii [The pale, primarily pastoral (sometimes sylvan) group] A. crocodilinus A. arvensis A. fi ssuratus

379

370 370 371 372 372 373 373 374 374 375 375 375 376 377 378

390 392 394 396 398 400 402 404 406 408 412 416

T able of C onte nt s [The pale sylvan group] A. sylvicola A. cretacellus A. cruciquercorum sp. nov. A. abruptibulbus A. reducibulbus sp. nov. A. moronii sp. nov. A. sandianus sp. nov. A. sp. ‘RWK 2283’ A. summensis A. albolutescens A. didymus sp. nov. A. gemellatus sp. nov. A. inapertus A. mesocarpus sp. nov. A. diospyros sp. nov. A. hybrid ‘RWK 2021’ Other Entities in Section Arvenses A. fabaceus A. magniceps A. variabilis A. amygdalinus A. arvensis var. palustris A. sp. ‘RWK 2049’ A. cf. tenuivolvatus A. sp. ‘RWK 1978’ A. cf. macrocarpus A. sp. ‘RWK 2214’

420 422 426 428 434 436 438 440 442 446 448 452 454 456 458 460 462 463 463 465 467 469 469 470 471 472

Other Lineages Not Yet Named, Possibly Not Originating Within the Accepted Monophyletic Sections The ‘floridanus’ Lineage A. floridanus A. sp. ‘RMC 1256’ The ‘longuloid’ and ‘gyrophragmioid’ Lineages A. deserticola A. sp. ‘RWK 1048’ A. evertens sp. nov. A. zelleri nom. nov. Araneosa columellata The ‘martineziensis’ Lineage A. martineziensis

477 478 480 482 484 486 488 490 492 493 494

Other Species in the Literature The Agaricus (sensu strictu) Contributions of C. H. Peck The Agaricus Contributions of W. A. Murrill The Agaricus Contributions of A. H. Smith The Agaricus Contributions of B. F. Isaacs The Agaricus Contributions of A. E. Freeman

497 498 508 511 513

xii

T able of C onte nt s Literature Cited

517

Types Critically Examined

524

Vouchers Studied and/or Sequenced, and Accepted

525

Nomenclatural Citations: Species and Infraspecific Taxa Presented in This Work

536

Index to Scientific Names Now (or Formerly) Assigned to Agaricaceae, With Prior Homonyms

568

Agaricus bisporus, a member of section Bivelares, subsection Hortenses. Collection RWK 1964, from under planted Norway spruce, Armstrong Co., Pennsylvania, Ă&#x2014; ~1.0. The aspect is very similar to some authentic illustrations of A. brunnescens.

Agaricus sipapuensis Kerrigan sp. nov. HOLOTYPE: Specimen RMC 1272. Near Sipapu Ski Resort, Taos Co., New Mexico, USA, 26 August 2010. Leg. R. M. Chapman, deposited in SFSU herbarium. MB 802525

Affinities Section Bivelares subsection Hortenses; closest to A. bisporus.

N o ta b l e F e at u r e s Blunt-lapped to acute fibrillose brown scales on cap; narrow ochraceous bands may be present below top of stem; many white fibrillose zones below ring on lower stem.

D e sc r i p t ion PILEUS 8–11 cm diam., becoming broadly umbonate to subplane, the disc sometimes depressed, margin even at maturity; pileipellis medium-dark brown, about 9E5–6E6, formed of radially oriented hyphae, forming blunt-subimbricate to pointed appressed-fibrillose squamae, except disc subentire, background whitish, not obviously discoloring; context 10–15 mm thick, whitish to dingy, without distinct color changes when exposed, odor mild, unremarkable. Lamellae free, close (12/cm at 1 cm from stipe), to 6 mm broad, medium pinkish- brown after pileus expansion, later dark blackish-brown. STIPE semi-equal 5.5–7.5 cm long × 15–20 mm; surface white, generally glabrous above, or with a few narrow ochraceous bands, covered below the annulus with many ranks of short white semierect fibrils, no color changes recorded; interior stuffed-hollow, the pith white, context possibly whitish but dingy toward maturity, slightly orangish below after exposure; base unremarkable. VEILS forming a thickmargined, supramedian, intermediate whitish annulus, fl aring 5–10 mm, puff y and striate

A. sipapuensis: collection RMC 1272 [Type]. Leg. R. Chapman, above Sipapu Ski Resort, Taos Co., New Mexico. × ~0.6. Photo courtesy of and © Robert M. Chapman.

A gari c u s S e c ti on B ive lare s above, margin grooved to twolayered, the PV smooth, pale, and semi-entire underneath, the UV with some indistinct brown flaps near the stipe. SPORES dark brown at maturity, broadly ellipsoid, (6.1–) 6.6–6.8 (–7.8) × (5.1–) 5.5–5.8 (–6.5) μ m, mean = 6.7 × 5.6 μ m, L/W = 1.20 (N = 60, C = 2); hilar appendix prominent; apical pore not evident. BASIDIA predominantly tetrasporic, cylindro-clavate, 25–34 × 7–10.5 μm; sterigmata 3–4 μ m long. CHEILOCYSTIDIA about cylindrical to broadly clavate, clumped, semicontinuous, 19–25 × 6–13 μm.

RWK 2263. Taos Co., New Mexico. × ~0.65.

C h e m i s t ry KOH unchanging; A+A unchanging.

H a bi t, H a bi tat, D i s t r i bu t ion Solitary or in pairs, under Picea, very close (1–2 m) to bank of stream, ca. 2400–2500 m elev., Sangre de Cristo Range, New Mexico. August.

Et y mol o g y This species was found both at and near the Sipapu Ski Resort in New Mexico, site of the 2010 NMMS Foray.

D i sc u s s ion Agaricus sipapuensis, a rare species that is not yet well known, might be taken for a member of section Subrutilescentes; however, KOH placed on the pileipellis produces no color change. Odor of the fresh mushrooms was mild and unremarkable. The best clue to its relationships (in section Bivelares) comes from the annulus, which sheathes the stipe upward for only a short distance, and terminates in a sharp boundary, thus is technically of the “intermediate” type. The narrow ochraceous bands sometimes seen near the stipe apex (see photograph at left) are very unusual in Agaricus. Based on ITS DNA sequence analy sis, A. sipapuensis is most closely related to A. bisporus. Section Bivelares was thought to be reasonably well known prior to the discovery of this species in 2010. Both of the known New Mexico collections were made within 0–2 km of the Sipapu Lodge.

E di bi l i t y Unknown

Agaricus cordillerensis Kerrigan sp. nov. Holotype: Specimen RWK 1616. Banff Township, Alberta, Canada, 31 July 1990. Leg. R. W. Kerrigan, deposited in SFSU herbarium. MB 802541

Affinities Section Sanguinolenti, subsection Sylvatici; close to A. hupohanae.

N o ta b l e F e at u r e s Somewhat slender, erect stature; brown, appressed fibrillose-squamulose cap; mildly red-staining flesh.

D e sc r i p t ion PILEUS ca. 5–13 cm diam., convex or broadly conic-truncate; pileipellis medium brown (ca. 6C6–6D8), often darkening in maturity (to 7F6–8F7), formed of semiradially oriented hyphae, forming small, appressed-pointed squamules (or these obscure, the surface approaching innately fibrillose), except disc more entire, background whitish; context ca. 6–10 mm thick, whitish, becoming slightly pinkish-red when exposed, odor mild to fruity- spicy. Lamellae free, close, 4–7 mm broad, possibly obscurely marginate (paler). STIPE subequal or slightly tapered upward, with a very slight bulb, 7–12 cm long × 12 (–20) mm above, 25 (–35) mm below; surface glabrous above, with some fibrillose to scurfy velar remnants below, white, becoming pinkish-red when incised, or (RWK 2054) the surface becoming yellowish-buff, lustrous and

A. cordillerensis: collection RWK 1616 [Type, SFSU]. Banff, Alberta. × ~0.9.

208

A gari c u s se c ti on S ang ui nole nti fibrous in age); interior stuffed-hollow, context whitish, slightly to moderately rufescent, particularly at and near the apex, or (RWK 2054) pale salmon-colored throughout); base fairly shallowly rooted. VEILS initially forming a fl aring, subapical to supramedian pendent white annulus (no longer present in RWK 2054), with a blunt, 1 mm thick margin fringed below with small brown UV points, undersurface with many innate fibrils adhering to the stipe, also with a few scurfy to many fibrillose white velar remnants on the lower stipe. SPORES dark brown at maturity, ellipsoid, (4.3–4.9–) 5.6–6.4 (–7.2–7.7) × (3.7–3.8–) 4.1–4.5 (–4.9–5.1) μm, mean = 5.9 × 4.3 μm, L/W = 1.37 (N=120, C=4); hilar appendix generally prominent; apical pore not evident. BASIDIA predominantly tetrasporic, clavate, 19.5–28.5 × 6–7.5 μm; sterigmata ca. 2–2.5 μm long. CHEILOCYSTIDIA semicylindrical to slightly or occasionally clavate, frequently slightly and irregularly narrower centrally, (10–) 13.5–21 × 5–8 (–9) μm, continuous.

C h e m i s t ry Unavailable

H a bi t, H a bi tat, D i s t r i bu t ion Solitary, paired, or gregarious under spruce, at high elevations in mountains of the Laramide Belt of the Western North American Cordillera, in Colorado, New Mexico, Utah, and Alberta. July–August. Fairly common under mature spruce in Grand Co., Colorado.

Et y mol o g y A species of the interior western cordillera of North America.

D i sc u s s ion Agaricus cordillerensis appears to be the most common slender brown- capped Agaricus of the Rocky Mountains. In appearance it is something of a chameleon, as both the degree and nature of ornamentation on the pileus surface, and the color and uniformity of surface pigmentation, vary depending on circumstances. Older pilei can be quite dark, and specimens can be more slender than RWK 1616, especially in deep needle litter under spruce, for example above Fraser, Colorado, where several collections were made. The distinct ITS sequence places it in subsection Sylvatici, with several other species, close to A. hupohanae from New Mexico. Agaricus sylvaticus (all subspecies) has a considerably different ITS sequence.

E di bi l i t y Unknown

209

Agaricus sp. ‘NY 49276’ Unpublished

Affinities ‘TRc’ lineage (Zhao et al., 2011), close to A. sp. ‘ASM 13217.’

N o ta b l e F e at u r e s Moderate size and stature; brown appressed-squamulose cap; stipe surface lustrous, becoming yellowish-reddish-brown when handled; known from New York.

B r i e f D e sc r i p t ion (provided by R. E. Halling) “[Pileus] 3–8 cm broad, dark brown over disc, fi nely appressed squamulose toward margin. Stipe bruising reddish to orangish brown, equal, 7–8 cm long, 10–12 mm broad, with ample partial veil, appearing with a slight band on underside when still intact. Odor not phenolic, not almond. . . . KOH (- [no reaction]). Growing on lawn near Styrax, Prunus and pine. New York Botanical Garden, Bronx, New York. October.” My microscopic observations: SPORES dark brown, ellipsoid (5.1–) 5.3–5.4 (–5.7–6.3) × (3.2–) 3.5–3.6 (–4.0) μm, mean size 5.4 × 3.6 μm, L/W = 1.51 (N=30, C=1); hilar appendix prominent; apical pore not evident. BASIDIA clavate to broadly so, ca. 18.5–24 × 7.0–8.5 μm, sterigmata ca. 2.5–3 μm long. CHEILOCYSTIDIA abundant, continuous in a deep layer, most often broadly clavate, appearing subglobose, and potentially even catenulate, if not well separated and seen in profi le, 25–34 × 12–15.5 μm.

260

O th e r ‘ sang ui nole nt ’ L i neag e s

Agaricus sp. ‘NY 49276’ has an ITS sequence that is almost identical to that of ASM 13217; however, the microfeatures are very different, and they are separate species. They are both related to the ‘TRc’ lineage of Zhao et al. (2011) and to at least one Australian species (‘A’ of Lebel & Syme, 2012). NY 49276 has a fairly strong resemblance to A. rubribrunnescens as described, and was in fact collected at the type locality. However, based on the dimensions of the stipe, and the “slightly fibrillose” stipe character of A. rubribrunnescens, the species exemplified by collection RWK 2005 is a closer fit to Murrill’s description. All of these species appear to be rare and incompletely known. Edibility is unknown.

261

Agaricus moellerianus Bon Psalliota campestris var. floccipes F. H. Møller, Friesia 4(1–2): 57. 1950; Agaricus. floccipes (F. H. Møller) Bohus, Ann. Hist.-Nat. Mus. Nat. Hung. 70: 107. 1978, nom. illeg. [non A.(Hydropus) floccipes Fr., Epicr. Syst. Mycol.: 87. 1838.]; A. moellerianus Bon, Doc. Mycol. 15(60): 6. 1985 [as nom. nov. based on A. floccipes (F. H. Møller) Bohus].

Affinities Section Agaricus; close to A. porphyrocephalus.

N o ta b l e F e at u r e s Moderate size, sturdy stature; broad pallid cap, becoming yellow in age or when dried; equal stem; scant ring; short, broad spores; growing in lawns, or possibly under cypresses.

D e sc r i p t ion (from Møller 1950) “Pileus 3–6 cm, white, turning yellow (“Straw Yellow”) when touched, often very silky and naked, when dry breaking up into thick diamond-shaped scales. Gills rather narrow, bright red (“Vinaceous Pink”) in the expanding stage. Stem 3–4 cm × 10–20 mm, above the weak ring densely floccosesquamulose as in a Hebaloma species. Flesh thick, smelling of almonds. Spore powder dark brown (“Mars Brown”) . . . Spores 6–7 × 4–5 (–6) μ. Basidia 22– 36 × 6–9 (–12) μ. In old pastures and meadows, often in quantity. September– October.” This species is known in North Amer ica from two collections, with good photos, made by Gwyn Quillen at a site in Malibu, California, where it occurs regularly. Because detailed notes on these collections are not available, I have presented Møller’s original description of Psalliota campestris var. floccipes. The Malibu mushrooms are larger than what Møller knew. Gwyn provided the following information: Pileus diameter (3–) 8–9 (–11) cm, surface spontaneously beginning to turn yellow within hours of harvest; lamellae deep rosy pink when young; stipes 3–6 cm × 20–25 mm; fruiting for about two months after the first winter rains (December–January). The velar remnants on the stipe above the scant annulus were extremely obscure. The lamellae as photographed had a pronounced “flesh” (dull pink) tone without the “bright red” color reported by Møller. Other descriptions will be found in Bon (1985) and Parra (2008). My microscopic data on GQ-1: SPORES dark brown, broadly ellipsoid, ranging (5.5–) 6.1–6.2 (–6.8) × (4.5–) 4.9–5.2 (–5.5) μm, mean size 6.2 × 5.1 μm, L/W = 1.22 (N = 30, C = 1); hilar appendix moderate to An unnumbered Malibu collection. Height = 72 mm. prominent; spore apex occasionally thinLeg. (and photo courtesy of and ©) G. Quillen. × ~1.05. walled. BASIDIA cylindro- clavate, predom-

294

A gari c u s S e c ti on A gari c u s

Agaricus moellerianus: specimens GQ-1. Leg. (and photo courtesy of and © ) G. Quillen, Malibu, Los Angeles Co., California. Shown where collected. Per the collector, the mushrooms in the photo appear somewhat tan in color, whereas to the eye they appeared white.

inantly (?) tetrasporic, 18.5–21.5 x 6–7.5 μm, sterigmata ca. 2 μm long. Cells of the lamellar margin clavate, basidiole-like.

C h e m i s t ry Per Parra (2008), KOH faint yellow; A+A orange, but only on the yellowed parts of the pileus surface, while negative on the white parts.

D i sc u s s ion This mushroom grew in rings in a lawn in Malibu, on the California coast, where it occurs with regularity. It resembles A. campestris; however, the caps become a rich yellow color in age. The ITS DNA sequence matches those of A. moellerianus collections from France and eastern Europe. The dimensions observed by Gwyn are similar to those Parra (2008) reported for the species in Europe. It is a cousin of A. porphyrocephalus and a few other species on a branch at some distance from A. campestris. While clear photos are available, I have no comprehensive notes on any of the fresh specimens, so a full description based on North American material is not presently possible. The relatively small spores are distinctively broader than most others of section Agaricus (excluding the secotioid A. gastronevadensis).

E di bi l i t y According to Gwyn Quillen, it is regularly consumed by her and her dinner guests.

295

Agaricus martineziensis Heinem. Agaricus volvatus A. T. Martínez, Rev. Invest. Agr. Buenos Aires 11: 299. 1957, nom. illeg. [non A. (Amanita) volvatus Peck, Ann. Rep. New York State Mus. 24: 59. 1872]; A. martineziensis Heinem., Bull. Bot. Jard. Belg. 60: 339. 1990. [as nom. nov.].

Affinities Undetermined; ITS sequence suggests a possibly basally rooted lineage, or else a sequence with an unusual evolutionary history.

N o ta b l e F e at u r e s Young cap semispherical, brown fibrils developing into concentric zones, white margin ultimately projecting; thick, elongate saccate volva surrounding much of lower stipe, cheilocystidia multiseptate-fi lamentous.

D e sc r i p t ion (paraphrasing Martí nez [1957], Capelari et al. [2006], and Heinemann [1990, for microdata]) PILEUS 11–20 cm diam., semispherical, becoming broadly convex and finally plane, or slightly depressed centrally; pileipellis warm reddish-brown, “Cinnamon Brown” (of Ridgway, per Martínez), formed of radially oriented hyphae, disaggregating into uneven concentric zones of appressed fibrils, except disc remaining entire, background whitish, unchanging; white margin projecting; context white, unchanging, odor weakly fungal, flavor weakly of almonds. Lamellae free, relatively narrow, long remaining white, then chestnut color with paler margin. STIPE

A. martineziensis: collection U.C. Peixoto (SP307818). São Paulo, Brazil. × ~0.45. Photographs courtesy of and © Marina Capelari.

494

O th e r L i neag e s N ot Y et N am e d equal or slightly tapered upward, 13–15 cm long × 15–30 mm; surface white, unchanging, smooth above and fibrous- squam[ul]ose below the annulus; interior narrowly stuffed-hollow, context white, with light yellowish grayish-brown stains mostly in the base when sectioned; base deeply rooted, sometimes with a grayish rhizomorph. VEILS forming (1) a fairly stiff, fl aring subapical pendent white annulus, slightly obscurely striate above, unadorned, margin thick, and (2) a thick appressed to free cup-like to elongate saccate volva, 4–7 cm long. SPORES very dark brown at maturity, “short ellipsoid,” (5.3–) 5.94 (–6.7) × (4.3–) 4.76 (–5.3) μ m, mean = 5.9 × 4.8 μ m; apical pore not evident. BASIDIA tetrasporic. CHEILOCYSTIDIA few, multiseptate, fi lamentous-cylindrical, the terminal element sometimes broader, clavate to balloon-shaped, 15–33 × 8–13 μm. Data from type.

C h e m i s t ry

KOH negative; aniline + acid on dried material negative; H2SO4 rosy on pileus.

H a bi t, H a bi tat, D i s t r i bu t ion Solitary or paired on bare soil in forest or with buried wood in an enclosure for raising chickens. Described from Argentina, known from Brazil, reported from Jalisco State, Mexico. February, June, November, December in South Amer ica.

D i sc u s s ion Agaricus martineziensis is a very distinctive species. The volva makes this obvious, while the multiseptate-fi lamentous cheilocystidia, with the terminal elements sometimes enlarged, are also noteworthy. The chemical reactions and the ITS sequence support the idea that this southern species belongs to an ancient lineage for which a sectional name has not yet been proposed. Tree-building algorithms put the ITS sequence of this species on very long branches (see also Zhao et al., 2011); either we have found no close relatives of it, or else the ITS sequence has evolved in an unusual way, for example, hypothetically, by saltation. Heinemann’s paraphrase of Martínez is too abbreviated. The description of Capelari et al. notes only the terminal elements of the cheilocystidia, but apparently refers to the same species. I include the species in this work because Guzmán (1977) reported it from a xeric habitat in Mexico. Per Bandala- Muñoz et al. (1988), Guzmán and García Saucedo (1973) recorded it from Jalisco, in western central Mexico. More confirmatory information about the species in North Amer ica should be developed. I thank Luis Parra for providing me with several papers on this species. I would also like to thank Marina Capelari and collaborators for their paper, photographs, and a DNA sample from which I obtained the ITS sequence of the specimen in the previous photograph.

E di bi l i t y Edible, but hardly delicious, per Martínez (1957).

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