The grass family, Poaceae (Gramineae) is considered the most valuable plant family in food production worldwide. In addition to its importance as a grain crop (e.g. maize, wheat and rice), its tolerance to grazing, fire and drought, makes grasses a significant component of livestock feed, mainly sourced from rangeland and/or planted pastures. Soreng et al. (2017) recognised at least 11 506 grass species worldwide of which approximately 685 species are indigenous to southern Africa (Trytsman et al. 2020).Considering that in southern Africa only eight indigenous grass species were extensively researched in the past century (Truter et al. 2015), the wealth of grass genetic resources, indigenous to the subcontinent, still needs to be prioritised, conserved and developed for forage production.The classification and distribution of southern African grasses that included Botswana, Namibia, South Africa, Lesotho and Swaziland were described by Gibbs Russell et al. (1990) and was updated by Fish et al. (2015). Studies on the biogeographical patterns of grasses in relation to southern African vegetation types are, however, limited. Then again, there are numerous phytogeographical studies on the southern African flora, which include those by