Spiny shrubs. Lvs 3-foliolate, petiolate; leaflets entire; lateral veins indistinct; stipules inconspicuous. Fls axillary and solitary, or in fascicles or ebracteate racemes; bracteoles usually 3-fid. Calyx tubular, with 5 short teeth; upper portion soon breaking away leaving a cup-like remnant. Corolla yellow. Stamens connate into a closed tube; alternate anthers long and basifixed or short and versatile. Style incurved, glabrous; stigma capitate or oblique. Pod flattened, ± straight or slightly curved, dehiscent, with upper suture somewhat thickened and usually winged, several-seeded; seeds estrophiolate.

Shrubs or small trees, not armed. Lvs 1- or 3-foliolate, petiolate or apetiolate; stipules small or 0. Fls yellow, white, reddish or tinged mauve, axillary or forming leafy, terminal racemes; bracts and bracteoles small, caducous. Calyx campanulate, bilabiate, usually < 5 mm long; upper lip shortly 2-fid or toothed; lower lip with 3, usually minute or indistinct teeth. 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.