Description from Flora of China
Herbs or shrublets. Vegetative and reproductive parts covered usually with viscid tubercular-based trichomes. Stems erect or creeping, often hollow. Stipules spurred below point of insertion, peltate or unilaterally auriculate, caducous. Leaves paripinnate, 20- to many foliolate, often sensitive; leaflets opposite, subsessile, with 1 midvein or 2 to several primary veins. Inflorescences usually axillary, usually racemose, with several flowers; bracts paired, stipule-shaped, not spurred, persistent or caducous, margin denticulate. Flower small to medium-sized. Bracteoles present. Hypanthium short. Calyx membranous, usually 2-lipped, abaxial lip 3-lobed, adaxial lip 2-lobed. Corolla usually yellow; standard orbicular, large; wings without an auricle; keels curved, with a small beak. Stamens diadelphous (5+5) or basally connate; anthers uniform. Ovary linear, with numerous ovules; style filiform, inflexed; stigma terminal. Legume a loment, compressed, stipitate, divided into 4-8 articles, surface often muricate. Seed 1 per article.
About 150 species: tropics and subtropics worldwide; two species (one introduced) in China.