Description from Flora of China
Prostrate or climbing herbs. Leaves 1-foliolate; stipules very caducous; stipels persistent. Racemes axillary or in a few-branched terminal panicle. Flowers solitary, paired or clustered at nodes of rachis of inflorescence; bracts deciduous or persistent; bracteoles persistent. Calyx tube campanulate, 5-toothed; upper 2 teeth connate from middle downward. Corolla exserted; petals subequal in length, clawed; standard obovate, elliptic, or suborbicular, with 2 minute, inflexed basal auricles; wings falcate or obovate-oblong, slightly adherent to keel at base; keel falcate or narrowly oblong, incurved, without auricle or nearly so. Stamens diadelphous, vexillary stamen free; anthers uniform, dorsifixed. Ovary sessile or subsessile; ovules numerous; style incurved, glabrous; stigma small, capitate. Legumes narrowly oblong or linear, compressed, septate between seeds. Seeds orbicular or oblong, with a thick strophiole at small hilum.
About four species: China, India, Thailand; one species (endemic) in China.
(Authors: Chen Dezhao (陈德昭 Chen Te-chao), Zhang Dianxiang (张奠湘); Mats Thulin)