A taxonomic revision of Raphionacme (Apocynaceae: Periplocoideae)

Raphionacme comprises 36 species and with the exception of one Arabian species, the genus is restricted to Africa, occurring widespread over the continent from the southern fringes of the Sahara Desert to South Africa. Most of the species are found in grassland and savanna. Vegetatively the genus consists of prostrate, erect or climbing herbaceous geophytes, typified by a usually spindle-shaped taproot tuber. The flower is typified by a distinct corolla tube, corona lobes and stamens that are basally fused and inserted in the corolla mouth, pollen in tetrads and individual grains 8–16-porate. The anthers and style-head are, furthermore, fused into a gynostegium and spoonlike translators are secreted on the style-head. Nomenclature, generic and species descriptions, a key to the species, geographic distribution and ecology of the species are presented.