Psophocarpus Neck. ex DC.

Legumes of the World. Edited by G. Lewis, B. Schrire, B. MacKinder & M. Lock. Royal Botanic Gardens, Kew. (2005)

Note

Previous accounts of the Phaseoleae by Baudet (1978) and Lackey (1981) recognised 90 and 84 genera and c. 1540 and 1480 species respectively in the tribe. In an equivalent, i.e. traditionally held view of Phaseoleae, 89 genera and (1554)–1567–(1580) species are treated here (Table 9; Fig. 47). Changes between Baudet (1978) and this treatment are that eleven genera are now in synonymy or have subsequently been placed in Millettieae, two genera have been transferred from Desmodieae and eight new genera have been added. Vigna has traditionally been thought to comprise some 150–200 species, but Vigna sens. strict. may contain fewer than 100.

Recent molecular analyses of the tribe, however, have emphasised both the polyphyletic and paraphyletic nature of Phaseoleae as traditionally circumscribed (Bruneau & Doyle, 1990; Doyle & Doyle, 1993; Delgado Salinas et al., 1993; Bruneau et al., 1995; Doyle et al., 1997, 2000; Kajita et al., 2001; Goel et al., 2001; Lee & Hymowitz, 2001). This has required a radical realignment of elements of the phaseoloids (Table 9; Fig. 47), with at least two major clades being evident: Phaseoleae subtribes Diocleinae and Ophrestiinae which together with tribe Abreae are allied to the core-Millettieae (Fig. 45), and the remaining groups comprising a Phaseoleae sens. lat. clade. The rbcL phylogeny of Kajita et al. (2001) and the ITS analysis of Hu et al. (2002) are equivocal as to which clade subtribe Clitoriinae belongs. Phaseoleae sens. lat. also includes two traditionally independent tribes, the Desmodieae and Psoraleeae. Delimiting a recircumscribed Phaseoleae sens. strict is thus very problematic. A solution may be to recognise a broad tribe Phaseoleae, comprising the subtribes Kennediinae, Cajaninae, Phaseolinae and Glycininae, assorted basally branching genera, and tribes Desmodieae and Psoraleeae (both treated at subtribal level).

Psophocarpus is basally branching in subtribe Phaseolinae (Bruneau et al., 1995), and placed further down the tree in a clade with Erythrina, sister to the combined Phaseolinae, Glycininae and Psoraleeae (Doyle et al., 2000)

Habit

Climbing herbs or subshrubs

Ecology

Seasonally dry tropical forest and forest margins, secondary vegetation, thicket, swamp, moist wooded grassland and grassland

Distribution

Africa and Madagascar, one widespread cultivated sp. (unknown in the wild), possibly Asian in origin; a further sp. introduced in the Mascarenes, Comoro Islands, Caribbean and S America

Leguminosae, B. Mackinder, R. Pasquet, R. Polhill & B. Verdcourt. Flora Zambesiaca 3:5. 2001

Morphology General Habit

Herbs or subshrubs, prostrate or climbing, rarely erect.

Morphology Leaves

Leaves pinnately 3-foliolate; stipules appendaged below the point of insertion; stipels present.

Morphology Reproductive morphology Inflorescences

Inflorescence an axillary pseudoraceme, subumbel or umbel; bracts and bracteoles present.

Morphology Reproductive morphology Flowers Calyx

Calyx 5-lobed, the upper pair of lobes fused for all or part of their length; lower lobes various.

Morphology Reproductive morphology Flowers Corolla

Corolla mostly blue or mauve, rarely yellow; standard auriculate, appendaged.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 10, 9 with filaments fused, 1 free to the base or connate in the middle.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary stipitate; ovules 3–many; style thickened above the ovary, bent, flattened towards the apex, bearded longitudinally or with a ring of hairs below the stigma; stigma terminal or subterminal, penicillate or not.

Morphology Reproductive morphology Fruits

Fruit narrowly cylindrical, 4-winged, septate, dehiscent.

Morphology Reproductive morphology Seeds

Seeds ovoid, oblong or square, brown to black or deep purple, with or without an aril.