The diversity and multiple uses of southern African legumes

Abstract

Southern Africa has a rich legume flora comprising 133 indigenous genera and 1620 indigenous species, of which 1059 species (65%) are endemic to the flora of southern Africa region. An additional 128 non-indigenous species have become naturalised, of which 59 are invasive, resulting in 1748 species from 165 genera. There are 22 (17%) endemic genera, one endemic tribe (Hypocalyptieae) and one near-endemic tribe (Podalyrieae, with 122 of the 123 species endemic). The diversity of uses (given as total/indigenous spp.) include food and beverages (127/115 spp.), medicine (338/291 spp.), magic and charms (113/104 spp.), timber (59/55 spp.), firewood (43/31 spp.) and 10 more minor use categories. Regression analyses showed that the levels of endemism in subfamilies and tribes are directly related to the numbers of species but that the number of useful species is not related to species numbers, except for the non-papilionoid subfamilies (all uses) and non-genistoid papilionoids (medicinal uses only). The Phaseoleae and Millettieae showed high residual values in several analyses, indicating that they have been favoured in the selection of useful plants. Diversity in habit and chemistry seems to explain at least partly the use patterns.