Cladistic analysis of Psophocarpus Neck. ex DC. (Leguminosae, Papilionoideae) based on morphological characters

Psophocarpus Neck. ex DC. (Leguminosae; Papilionoideae) is a genus of eight tropical African legume species and with a single cultivated Asian species P. tetragonolobus or the winged bean. Current increasing interest in the use of wild relatives as a source of adaptive traits for breeding has lead to an attempt to clarify the phylogenetic relationships within the genus. To test the monophyly of Psophorcarpus, a cladistics analysis was undertaken based on morphological characters recorded from herbarium specimens representing the nine species of Psophocapus with species of three related genera, Vigna, Otoptera and Dysolobium, as outgroups. The results indicated that the genus Psophocarpus is monophyletic and the nine species resolved into four subclades: subgen. Psophocarpus sect. Psophocarpus (P. palustris, P. tetragonolobus and P. scandens); subgen. Psophocarpus sect. Vignopsis (P. lancifolius and P. lukafuensis); subgen. Lophostigma (P. obovalis, P. monophyllus and P. lecomtei); and a new subgen. Longipedunculares (P. grandiflorus) which is herein proposed.

► This is the first attempt to suggest a phylogeny of the genus Psophocarpus.
► The results indicated that the genus Psophocarpus is monophyletic.
► The nine species of Psophocarpus are resolved into four subclades.
► A new monospecific subgen. Longipedunculares is herein formalised.