Description from Flora of China
Annual or perennial herbs. Stem erect, spreading or prostrate, much branched. Leaves pinnately 3-foliolate; stipules adnate to petiole, conspicuously veined; terminal leaflet usually larger, margin ± serrulate or incised, lateral veins running out into teeth. Inflorescence axillary, shortly racemose, capitate, subumbellate, or flower solitary; peduncles elongate in fruit. Pedicels short, often less than 5 mm, thickened after flowering; bracts minute; bracteoles absent. Calyx teeth ± equal. Petals yellow, blue, purple, or white, free from staminal tube; standard obovate or oblong, broad at base, sometimes broadly clawed; wings elliptical; keel obtuse, shorter than wings. Stamens diadelphous or nearly monadelphous; filaments not dilated; anthers uniform. Legume straight, falcate, or arcuate, compressed or terete, tapering at both ends, with reticulate coat. Seeds 1 to many, scabrous, warty or pitted.
About 55 species: mostly in Africa, Asia, Europe, Mediterranean region, and Oceania; eight species (two introduced) in China.