Description from Flora of China
Herbs, twining, with root tubers. Leaves pinnately (3 or)5- or 7(or 9)-foliolate; stipels small. Inflorescence axillary or subterminal and grouped into terminal panicle, racemelike; nodes swollen. Bracts and bracteoles small, caducous. Calyx campanulate; lobes shorter than tube, upper 2 connate, lowest 1 linear and other 2 much shorter. Standard ovate or circular, reflexed; wings obliquely obovate, shorter than standard; keels longest and inflexed or coiled. Stamens diadelphous; vexillary stamen free; anthers uniform. Ovary subsessile; ovules many, upper part reflexed, usually thickened, glabrous; stigma terminal. Legume linear, almost falcate, dehiscent, compressed, 2-cleft. Seeds without strophiole.
About eight species: mostly in E Asia, two species in E North America; six species (four endemic) in China.
(Authors: Sa Ren (萨仁); Michael G. Gilbert)