Shrub or tree up to 12 m. high; bark grey, scaly, rough. Young branchlets densely to sparsely pubescent, soon glabrescent. Stipules not spinescent. Prickles just below nodes, either in threes, up to 7 mm. long, the central one hooked downwards, the laterals ± curved upwards, or else solitary, the laterals being absent. Leaves: petiole glandular or not (gland about 0.5–0.75 mm. in diameter); rhachis ± pubescent, glandular between the top 1–5 pairs of pinnae, prickly or not; pinnae (2–)3–6 pairs, 0.5–1.5 (–2.4, very rarely to 4) cm. long; leaflets 8–18 pairs, 1–4(–7) mm. long, 0.5–1.75 mm. wide; linear- to elliptic-oblong, ciliate on margins only or ± hairy on surface, or wholly subglabrous, lateral nerves not visible or sometimes somewhat prominent beneath, apex obtuse to subacute. Flowers white or cream, fragrant, sessile, in spikes 2–10 cm. long on peduncles 0.7–2 cm. long, normally produced with the leaves; axis pubescent to glabrous. Calyx 2–2.75(–3.5) mm. long, glabrous to somewhat pubescent. Corolla 2.75–4 mm. long, exceeding the calyx, 5-lobed, glabrous outside. Stamen-filaments 4.5–7 mm. long, free; anthers 0.2–0.25 mm. across, with a caducous gland. Ovary glabrous, very shortly stipitate. Pods (Fig. 14/17, p. 52) usually grey-brown, sometimes pale or dark brown, dehiscent, densely to sparsely appressed-pubescent to -puberulous, oblong, straight, venose, rounded to acuminate at apex, (3–)4–14 cm. long, (1.3–)2–3.3 cm. wide. Seeds ± subcircular-lenticular, 8–12 mm. diam.; central areole small to medium, 2.5–6 × 2.5–5 mm., markedly impressed.