African Wildlife & Environment Issue 80

FAUNA, FLORA & WILDLIFE

Using Acacia karroo (now Vachellia karroo ) as the example, let me tell you a little more about what is almost certainly South Africa’s most numerous and widespread tree. Some notes on taxonomy I am sure many readers will be aware that at the July 2011 XVIII International Botanical Congress in Melbourne 'we' lost the name Acacia for our beloved African thorn trees forever, all 134 species! Thereafter those that were once Acacias , that had pom-pom inflorescences and paired, straight (or straightish) stipular spines, became Vachellia spp., and those with spicate, hairy caterpillar-like inflorescences and hooked spines and/or prickles belonged to the genus Senegalia . The outcry from the 'stealing' of 'our' name still reverberates among many. But the war was lost quite legitimately, the rules were obeyed to the letter (to me the blame for losing the war can be attributed to the silence of the African taxonomists who knew what was afoot but did nothing. [there is a name for such folk!]). Thus, the vast majority of the 1,000 Australian wattles retained the name Acacia (what has transpired since then is that the Australian species arguably belong to some five genera, so all their names will have to be changed too (he writes while smiling wickedly!). What irked many is that the wattles, almost without exception, are without spines and the name 'acacia' means ' a sharp point ' in Greek (referring to the spines on Acacia nilotica that was the first named Acacia by Linnaeus; the father of modern plant taxonomy from a specimen collected in Egypt in the early 1800s).The fuss made of losing the name of what are iconic African savanna trees was enormous, generated many scientific papers and articles, and caused huge angst that still exists today. However, when Acacia albida was changed to Faidherbia albida in 1934 there was little or no fuss (maybe because we in South Africa did not officially recognise this name change until the 1980s. By then the name had been widely accepted by knowledgeable tree amateurs! In the past, 'Pretoria', where the National Herbarium is located, used to rule on whether we could or could not implement taxonomic plant name changes, even though they were accepted internationally!. Another name change that went unnoticed was when all our species of Rhus became Searsia in 2007 – that seamless change still baffles me!

Figure 6. An iconic African thorn tree - A. tortilis (now V achellia tortilis )

Figure 7. Springbuck sheltering from the mid-day sun under an A. erioloba (now Vachellia eriolob a - Camel thorn)

Figure 8. A. sieberiana (Paper-bark thorn) woodland - another species that can have a very flat top.

Figure 9. Faidherbia albida that was once in the genus Acacia. This large tree was photographed in a dry river bed in northern Namibia

18 | African Wildlife & Environment | Issue 80 (2021)