A revision of the genus Bolusia (Fabaceae, Crotalarieae)

A taxonomic revision of Bolusia Benth. is presented. Diagnostic characters at generic level are the dentate stipules, the helically coiled keel of the flowers, the glabrous style and the chromosome number of 2n = 18. The five species recognised in this revision are all endemic to tropical Africa south of the equator. They are B. amboensis (Schinz) Harms, B. resupinata Milne-Redhead, B. ervoides (Welw. ex Baker) Torre, B. acuminata (DC.) Polhill and B. grandis B.-E. Van Wyk. One species from Tanzania is insufficiently known and no material is available for study. Bolusia is morphologically rather uniform, so that morphological characters do not allow for a meaningful analysis of phylogenetic relationships within the genus. ITS, rbcL and morphological data confirmed the sister relationship between Crotalaria and Bolusia. The revision includes a brief discussion of morphological characters, phylogenetic relationships, a key to the species, a distribution map, descriptions and synonymies, together with the correct nomenclature and typification of the genus and the species.