Systematics of subtribe Anthosperminae and the generic affinities of Anthospermum and Nenax (Rubiaceae: Anthospermeae)

Abstract

The last taxonomic treatment of the subtribe Anthosperminae was in 1986 by Puff., nevertheless, few attempts have been made to resolve the phylogeny and the inter- and infrageneric relationships within the subtribe. The genera Anthospermum L. (39 species) and Nenax Gaertn. (11 species) are considered the most difficult groups to distinguish. Anthospermum species are widely distributed in Sub-Saharaan Africa and Madagascar with the highest concentration of taxa in southern Africa, while Nenax species are restricted in southern Africa, south-western Cape Floristic Region. The two genera share common morphological and anatomical characters.