Liede, S. & Nicholas, A. (1992) A Revision of the Genus Pentarrhinum E. Meyer (Asclepiadaceae) Kew Bulletin 47(3) 475-490
Perennial, twining and climbing herbs. Leaves cordate. Inflorescences lateral, umbel-like cymes. Corolla deeply 5-lobed. Corona 5-lobed; lobes in side view obconic, trumpet or slipper-shaped forming a narrow cavity within. Pollinia pendent. Follicles lanceolate, ± beaked, echinate. Seeds narrowly winged.
Worldwide: 3 species in tropical and South Africa
Botswana: 1 taxon.