Shrub or small tree 1,5-9 m high, branching from near the base. Bark pale to dark grey- or reddish-brown to black, rough; young branchlets pale to dark grey- or reddish-brown, often as though whitewashed over a purplish background, sparingly to densely puberulous. Stipules spinescent, in pairs, up to 6 cm long, straight, slender, usually the same colour as the young branch-lets and sparingly to densely puberulous; other prickles absent. Leaves: petiole 0,3-1,4 cm long, adaxial gland often absent, when present usually just below the lowest pinna pair, slightly raised, round to oval, 0,6-1,4 x 0,5—1,2 mm; rhachis 5-21,5 cm long, sparingly to densely pubescent, with a gland at the junction of eacli of the top 1-3 pairs of pinnae; well-developed leaves with 15-36 pairs of pinnae (reduced leaves with as few as 9 pairs of pinnae sometimes also present); rhachillae 1,2-4,1 cm long; leaflets (11)18-26(32) pairs per pinna, 1,5-5 x 0,5-1,1 mm, linear to linear-oblong, apex rounded to subacute, margins glabrous or ciliate, glabrous abaxially. Inflorescences capi­tate, solitary or more usually fascicled, often crowded into an irregular terminal "raceme". Flowers white or pale pink, sessile; peduncles (0,6)1,1-2,2(2,9) cm long, sparingly to densely pubescent, usually glandular; invo-lucel at or above the middle or at the apex of the peduncle. Calyx cupular, white or pink, sparingly to densely pubescent, espe­cially at apices of lobes, tube 0,3-0,9 mm long, lobes up to 0,6 mm long. Corolla tubular, glabrous, tube up to 2,5 mm long, lobes up to 0,7 mm long, usually 2-4 times as long as the calyx. Stamen-filaments free, up to 5 mm long; anthers 0,2-0,25 mm across, with a deciduous apical gland. Ovary up to 1 mm long, glabrous. Pods pale to dark reddish-brown, 8-22 x 0,5-0,8 cm, arcuate, sometimes slightly constricted between the seeds, flat, longitudinally dehiscent; valves thin, glabrous to sparingly pubescent and glandular. Seeds olive-grey, 7-9 X 3-4,5 mm, oblong or quadrate, smooth, compressed; areole 3,5-4,5 x 1,5-2,25 mm.