Introduction The genus Ferocactus is not as widely grown in cultivation as it might be, and does not often receive the attention from growers that the plants need for best results. In the climates of the kinder States of the USA with the advantage of little danger of frost, many can be grown outdoors, and in these circumstances these plants do well. In the UK they can with advantage be placed outdoors in the summer months, when they will not be so liable to be disfigured with sooty mould, and will develop their spines to best potential. There are a handful of species that are smaller growing than most, which will flower at 15cm diameter or less, notably F. fordii subsp. borealis, F. viridescens, F. macrodiscus, and F. alamosanus and subsp. reppenhagenii. F. latispinus at this size too will produce buds in cultivation in the UK in late August to early September, but usually needs coddling by removal to a sunny position indoors in the dwelling house with higher temperatures than normally maintained in the glasshouse, else the buds tend to abort with the lower night temperatures and shortening days. Many of the larger growing species will oblige when they get to small football size, and this has proved to be the case in the last few years in Derek's collection in Norfolk, where flowers have also been forthcoming on F. chrysacanthus, F. cylindraceus (and subsp. eastwoodiae), F. echidne, F. emoryi (and subsp. rectispinus), F. glaucescens, F. gracilis (and subsp. coloratus and subsp. gatesii), F. histrix, F. peninsulae (and subsp. santa-maria and subsp. townsendianus), F. pilosus, F. schwarzii and F. wislizeni.
British Cactus and Succulent Society. The authors have taken into account Lindsay's doctoral thesis on the genus of 1955, published with additional material by other Ferocactus enthusiasts, including research on the DNA analysis by J. Hugo Cota, when he was working at the Department of Botany, Iowa State University and the Centro de Educacion Ambiental e Investigacion Sierra de Huautla (CEAMISH) at the Universidad Autonoma del Estado de Morelos, Mexico. We have also been influenced to some extent by the treatment of the genus by Gottfried Unger in his massive book Die grossen Kugelkakteen Nordamerikas, some of whose theories we have some sympathy with. Franziska and Richard Wolf's lovely books Baja California und seine Inseln (1999) and Die Ferokakteen der Baja California (2004) have been enlightening too with many habitat photographs taken on the islands around Baja California, most of which they visited. The species of various other genera which have been assigned to this genus are covered in the chapter called 'Referred and other superfluous names', with an indication of the genus to which they are more generally considered to belong; also in this part of the book are those other Ferocactus names which have been applied to the accepted species of the genus, with their application indicated. So, if you do not find a name you seek in the first part of the book, in the 'Species commentary', look for it in the 'Referred' chapter. If you do not find it there either, it may mean that it is a catalogue name with no validity, has not been validly published, or has been published after the publication date of this book.
They undoubtedly benefit from being potted on every two or three years at least, to encourage them to grow to flowering size that much more quickly, although age has some relevance in this area, and there are underpotted plants in some people's collections which have been virtually dwarfed, producing flowers at what seems an unnaturally small size - but this is not to be advocated for best results. Recommendations for growing them successfully are included in the chapter on cultivation. The species included here are mostly those which are recognized by Nigel Taylor in his review of the genus published in 1984 in Bradleya, the yearbook of the
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Fig. 2 (opposite page): The tall columns of F. cylindraceus subsp. lecontei on a steep hillside in eastern Arizona, USA
