New species of Asclepias (Apocynaceae), Baphia (Leguminosae), Cochlospermum (Bixaceae) and Endostemon (Lamiaceae) from the Kalahari sands of Angola and NW Zambia, with one new combination in Vangueria (Rubiaceae)

Four new species are described from central and eastern Angola and adjacent NW Zambia. All occur in Kalahari sand savannas rich in endemic and more widely distributed geoxylic suffrutices. Despite being known from very few collections, the conservation status of one of these new species is assessed as Least Concern, as these grasslands are nutrient-poor, are in remote sparsely populated areas, and are not threatened with conversion to agriculture. The remaining three are treated as Data Deficient. In addition, one new combination is provided for Ancylanthos rubiginosus Desf. under Vangueria as V. rubiginosa (Desf.) Lantz is an illegitimate later homonym. We also make orthographic corrections to specific epithets commemorating Ilse von Nolde, a collector who made important collections from Quela in Malange in the 1930s.