Derris Lour.

Woody climbers, less commonly trees or erect shrubs. Leaves imparipinnate, sometimes only pinnately 3-foliolate; stipules mostly small and caducous; stipels present or absent; leaflets opposite. Flowers in terminal and axillary well-developed or contracted and subracemose panicles, but always with flowers crowded on the short ultimate branches or clustered at the nodes; bracts and bracteoles small. Calyx usually cupulate and sub-truncate or with only very short teeth of which the upper 2 are practically united. Corolla much longer than calyx, white, pink or purplish, usually glabrous; standard ovate to obovate or suborbicular, sometimes with auricles or calluses at base of the blade; wings adhering to keel-petals, usually with a conspicuous fold or pocket on basal part of the blade; keel-petals little curved, lightly coherent on the lower side towards tips. Stamens united into a tube closed above but with openings at base either side of the vexillary stamen (the latter may be free in young bud); anthers dorsifixed. Ovary often subsessile, few-ovulate; style curved and tapered to a very small terminal stigma, glabrous or the lower part covered with hairs like those of the ovary. Fruit flattened, indehiscent, elliptic to linear-oblong with wings along upper or both edges (sometimes and not in East Africa the wings little developed), usually subsessile, papery to coriaceous, 1–few-seeded. Seeds oblong-reniform to broadly reniform, smooth or wrinkled, with a small hilum; rim-aril small, sometimes detaching with the rather persistent funicle.