Trees, to 10 m high, sparsely armed with short straight or recurved prickles. Leaves bipinnate, alternate; stipules spiniform, to 3-5 mm long; rachis 20-40 cm long, slender, pubescent, pulvinate; pinnae 10-14 pairs, 2.5-10 cm long, slender; a spine present at the junction between pinnae pairs on the upper side; leaflets20-40, opposite, subsessile; lamina 1-2.5 x 0.5-1 cm, oblong, base oblique, obtuse, apex obtuse, emarginate, margin entire, glabrous, coriaceous; lateral nerves 5-15 pairs, pinnate, faint, intercostae obscure. Flowers bisexual, yellow, in supra-axillary and terminal racemes; pedicels 1-2 cm long; sepals 5, unequal; petals 5, orbicular, subequal, with red spot at the base; stamens 10, declinate, densely woolly at base; ovary half inferior, grey-velvety. Fruit a pod, 7-10 x 3-4 cm, obliquely oblong, black, glabrous; seeds black, oblong or ellipsoid.