Book Review:
Iridaceae of Southern Africa. Peter Goldblatt & John Manning. Strelitzia 42. 2020. Available from SANBI.by Nick Helme
This is a monumental work: all 1210 species and 36 genera of southern Africa Iridaceae are described and reviewed in a single tome weighing 2.5kg and with 1160 pages. This sure is not a field guide but it is the go-to work for the family for the foreseeable future.
This is the first comprehensive treatment of the entire family for over a century, during which time the number of known species in the region has almost doubled. It covers South Africa, Namibia, Botswana, Lesotho and Eswatini. The authors have a combined experience of some 75 years and are the acknowledged gurus of Iridaceae in the region. Between them they have also produced perhaps the bulk of the useful literature on the southern African flora in the last forty years, in the form of field guides and revisions of other taxa, dwarfing the outputs of nearly all other southern African plant taxonomists.
Southern Africa is home to about half the genera and 60% of the species in this well-known and well-loved family and this is thus a very important publication in a global perspective. By far the majority of the species are restricted to the winter rainfall Greater Cape Floristic Region but the Drakensberg escarpment is the other clear hotspot of diversity and endemism (as it is for many other families and taxa as well). Paging through the book and its distribution maps, one of the striking things is just how diverse the family really is and secondly, how localized so many of the species are – probably a good 10% are known only from a handful of localities. And new species are being found every year – in fact just since publication two new Moraea species have been discovered in the Cape (in the Cederberg and near Worcester), taking this genus up to 211 known species, by far the biggest genus in the family. In some cases the propensity to flower well only in the first few years after fire is a factor in their late discovery and this is often combined with a very localised distribution (less than 10 x 10 km), short flowering duration and the fact that several taxa open up only in the late afternoon (4-8 pm). New species are popping up in the heavily impacted Cape lowlands and in the more intact mountain regions and many are of course severely threatened – not surprising given their very localized distributions. Indeed, quite a few recently discovered species remain known only from Type collections and may in fact already be extinct, or very close to extinction. About 25% of the South African Iridaceae (over 300 species) are listed as threatened in the Red List of South African Plants and the family has the dubious distinction of being the family with the largest number of threatened plants in the country. Understanding the taxonomy and distribution of the species is key if these species are to be conserved and this is perhaps the single greatest tangible benefit of a production like this.
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| An example of some of the plates from this book |
Keys to the genera are provided, along with generic descriptions, keys to all species in each genus, plus distribution maps for every species, full descriptions of every species, comprehensive references for each genus and diagnoses with key specific characters highlighted. There are photos of some of the species and line drawings of others but not all species are illustrated. There have been extensive taxonomic changes within the family over the last century and this is the definitive guide to the current situation.
Find space on your botanical bookshelves for this incredible production.
To order this book, contact Thembi at sanbibookshop@sanbi.org.za, call at +27 12 843 5099, or download the order form by accessing the link below.
http://biodiversityadvisor.
About the author: Nick Helme is a botanical consultant, based in Scarborough, Cape Town. After extensive biological survey work in Bolivia, Cameroon and Madagascar, in 1998 he started undertaking botanical and ecological assessments in the Western and Northern Cape (mostly in the Greater Cape Floristic Region) and to date has compiled almost 2000 surveys and impact assessments. Nick is a primary author of assessments for the SANBI Red List of South African Plants, and was co-author of the Fynbos Forum Ecosystem Guidelines and of the Fynbos chapter in the SA Vegetation Map publication. Nick has published over 20 peer reviewed scientific papers, more than 25 popular articles, has collected over 10 500 plant specimens, and has discovered more than 90 previously undescribed plant species in the Cape region alone (including at least 10 Iridaceae), some of which he has helped describe in taxonomic journals. There are very few parts of the Greater Cape Floristic Region with which Nick is not familiar and he is constantly on the hunt for rare and poorly known plants. He posts all his botanical observations (currently over 11 500) on the biodiversity website inaturalist.org.
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