Description from Flora of China
Herbs or climbing subshrubs, twining. Leaves pinnately 3-foliolate; stipules and stipels persistent. Inflorescence axillary, racemose; flowers medium-sized. Bracts and bracteoles small. Calyx tubular, mouth obliquely truncate, lobes inconspicuous or absent. Corolla yellow or light yellow, longer than calyx; petals all long clawed; standard usually obovate, rarely oblong or broadly elliptic, glabrous, with auricles; wings falcate-oblong, oblong, oblong-elliptic, or elliptic; keels usually slightly shorter than wings. Stamens diadelphous; vexillary stamen free; anthers uniform. Ovary shortly stipitate, linear; ovules 4 to many; style filiform, dilated and hollow near middle, apical part cylindric, not barbate; stigma terminal, capitate. Legume linear, dehiscent, compressed, constricted between seeds, not septate, with persistent, membranous, cylindric calyx at base. Seeds usually black or blue, subglobose; hilum short, central; aril not developed.
About ten species: S Africa, Asia; nine species (five endemic) in China.
(Authors: Sa Ren (萨仁); Michael G. Gilbert)