Tree to 15 m high; trunk to 0,6 m diam., often with persistent prickles up to 1,5 cm long arising from swollen bases (knobs); crown often somewhat flattened and spreadÂing. Bark pale to dark yellow or yellowish-brown, fissured, flaking or peeling off to reveal a whitish inner layer; young branch-lets creamy-white to light grey-brown, puberulous or pubescent, seldom subÂglabrous. Stipules not spinescent, in pairs, linear, 1,5-3,5 x 0,2-0,8 mm, soon deciduous. Prickles in pairs just below each node, occasionally absent, strongly recurved, usually broad-based, 3-15 mm long, straw-coloured to brown or blackish. Leaves: petiole 0,5-4 cm long, adaxial gland variable in position, often a short distance below the lowest pinna pair, usually slightly flattened, discoid or oblong, 1,5-4 x 1,5-3 mm; rhachis 5,6-20 cm long, puberulous or pubescent, rarely subglabrous, lower surface often with recurved prickles up to 3 mm long, a fairly large gland at the junction of the top 3-16 pinnae pairs; pinnae (6)14-35(45) pairs; rhachillae 1,2-5,5(7) cm long, puberulous or pubescent, rarely subglabrous; leaflets 20-60 (68) pairs per pinna, 2-5(6) x 0,4-0,9(1,25) mm, linear to linear-triangular, apex subÂacute to narrowly obtuse, usually pubescent on the margins only, the midrib and someÂtimes a few small basal nerves visible below. Inflorescences spicate, solitary or fascicled, usually produced with the new leaves. Flowers yellowish-white or cream, sessile or nearly so; spikes 3-12 cm long; peduncles 0,5-3 cm long, puberulous to densely tomentose, rarely subglabrous, often glanÂdular. Calyx puberulous or pubescent, rarely subglabrous or puberulous on the lobes only, tube 0,7-1,8 mm long, lobes 0,2-0,8 mm long. Corolla subglabrous or puberulous, often only the lobes puberulous, tube up to 2,5 mm long, lobes up to 1 mm long. Stamen-filaments free, up to 6 mm long; anthers ± 0,1 mm across, with a deciduous apical gland. Ovary up to 1,2 mm long, glabrous, shortly stipitate. Pods brown, 6,5-12(15) X 0,9-1,7(2) cm, oblong, straight or almost so, usually acuminate apically, longitudinally dehiscent, coriaceous, venose, glabrous or subglabrous, rarely puberulous. Seeds sub-circular to elliptic-lenticular, 7-9 X 6-8 mm, compressed; central areole 3-4 X 2,5-3,5 mm, horse-shoe shaped, not impressed.
