Medium to tall perennial shrubs; stems well-branched, spinescent. Leaves usually alternate, initially trifoliolate, reduced to scales or spine-like phyllodes on mature plants, sessile; stipules absent. Flowers axillary, borne singly or rarely clustered in racemes or umbels; bracteoles 2, broad; bracts small. Calyx 2-lipped to the base, 5-toothed, membranous, persistent, upper lip 2-toothed, lower lip 3-toothed; petals clawed, yellow; standard ovate; wings obtuse, narrow; keel obtuse, lower margin pilose; stamens monadelphous, anthers alternately long and short; ovary sessile, style incurved, glabrous, stigma subcapitate, terminal, ovules many. Pod ovoid to linear-oblong, compressed or turgid, densely hairy, barely exserted from calyx, explosively dehiscent; seeds 1–6, arillate.
