Abstract
M.Sc.
A taxonomic revision of the genus Rafnia Thunb. (= Oedmannia Thunb., Vascoa DC.,
Pelecynthis E. Mey), a relatively poorly known papilionoid legume genus, is presented.
Rafnia (family Fabaceae, tribe Crotalarieae) is subendemic to the fynbos region of the
Western and Eastern Cape Provinces of South Africa, with one species having a
distribution area reaching into KwaZulu-Natal. The species delimitation has been
unsatisfactory, and the relationships among the taxa uncertain. Rafnia is divided into two sections and 19 species are recognized, compared with the 22 species previously distinguished by Harvey (1862). There are five new species and four species are subdivided into subspecies, eight of which are described for the first time. There are eight changes of status and one new combination is made. Rafnia constitutes a total of 31 taxa.
Morphological data used to investigate relationships among the species of Rafnia are
analyzed phenetically and cladistically and keys to the sections, species and subspecies, complete nomenclature, typification, descriptions as well as the geographical distribution for each of the taxa are presented. Proposals are made to resolve troublesome uncertainties regarding the nomenclature and typification of some species. The scope of this study did not permit detailed investigation into chemical or molecular evidence, although preliminary studies showed that such data would improve the understanding of the infrageneric relationships within the genus. Characters and character states show much variation, but an hypothesis of the phylogenetic relationships amongst the taxa is nevertheless presented. An in-depth study of morphological characters in particular has resulted in a better understanding of taxonomic relationships at the generic and infrageneric levels in Rafnia.