Shrubs or small trees, usually not armed, rarely spinous. Lvs 3-foliolate, petiolate; stipules inconspicuous. Fls usually yellow, rarely white or purple, in leafy axillary racemes or fascicles, or terminal heads; bracts and bracteoles caducous. Calyx tubular, bilabiate, usually > 5 mm long; upper lip shortly 2-toothed; lower lip shortly 3-toothed. Stamens connate into a closed tube; alternate anthers long and basifixed or short and versatile. Style glabrous; stigma terminal. Pod 2-valved, ± straight, explosively dehiscent, few- to many-seeded; seeds strophiolate, smooth.