Description from Flora of China
Perennial herbs or subshrubs, twining. Leaves pinnately 3-7-foliolate; stipules and stipels persistent. Inflorescence axillary, 1- or 2-flowered. Flowers large and beautiful; bracts paired, stipulelike, persistent; bracteoles similar to bracts or slightly larger, or sometimes leaflike. Calyx membranous, tubular, 5-lobed; lobes lanceolate or triangular, equal to or shorter than tube. Corolla longer than calyx; standard large, almost applanate or sometimes cucullate, abaxially minutely hairy, base clawed, without auricles; wings and keels much shorter. Stamens diadelphous; vexillary stamen free, or ± connate; anthers uniform. Ovary with stipe, with sheathing disk at base; ovules many; style complanate, long, curved, interior with beard. Legume stipitate, linear or linear-oblong, dehiscent, compressed or inflated, filled with soft tissue but not septate. Seeds subglobose or ellipsoid, compressed; hilum small, central or subcentral, strophiole absent.
About 70 species: tropics and subtropics of the world; five species (one introduced) in China.
(Authors: Sa Ren (萨仁); Michael G. Gilbert)