Erect or ascending annual or perennial herb or subshrub to 1 m tall; stems glabrous or grey-pubescent. Leaves pinnately trifoliolate, to c. 10 cm long; leaflets ovate or elliptic, 1–5 cm long, 5–30 mm wide, both surfaces usually minutely hoary and dotted with glands, apices obtuse, mucronate, margins irregularly toothed; terminal petiolule 5–15 mm long; stipules triangular, acuminate, to c. 4 mm long. Inflorescence rachis 5–15 cm long; peduncles 4–30 cm long, longer than subtending leaves; flowers mostly in 3s along rachis; pedicels c. 1 mm long; bract ovate-acuminate, to c. 2 mm long, hairy. Calyx campanulate, 2–3 mm long, tomentose, teeth unequal, upper 4 shorter than calyx tube, lower one larger and longer than others, as long as calyx tube; corolla 3–4 mm long, blue or pink-purple. Pod reniform, c. 3 mm long, slightly exserted, strigose-pubescent, warty, brown; seed 1, to c. 3 mm long, yellow. Flowers mainly Oct.–May.