A New Species of Vigna (Leguminosae: Papilionoideae) from Southern Africa

Abstract

On a plant collecting mission in the Eastern Highlands of Zimbabwe in January 1987, a plant community was found at the edge of Udu Dam, Nyanga containing Vigna oblongifolia A. Rich. and what appeared to be another Vigna species which, while superficially similar, was clearly distinct due to the darker and shorter leaves and the distinctly winged peduncles. Although the unknown species had small flower buds, no open flowers or pods were apparent. The site was revisited in April and flowering specimens and a few ripe pods were collected. After comparison with herbarium sheets and published descriptions (Wilczek 1954; Verdcourt 1970, Gillet et al. 1971; Mar&chal et al. 1978) it became apparent that this was a previously undescribed species belonging to subgenus Haydonia (Wilczek) Verdc. Two other specimens of this taxon, which had also been collected at Nyanga, were found in the National Herbarium, Harare. During examination of material at the herbarium of the Botanical Research Institute, Pretoria, a further sheet of this taxon was found, labelled Vigna venulosa (Huntley 3424). This specimen was collected in Angola and is distinct from the other material labelled V. venulosa which mainly has a West African distribution.