Shrub or small tree up to 7.5 m. high; trunk usually branching a short distance above ground; bark peeling off in large papery pieces, reddish- or greenish-yellow. Young branchlets glabrous except for minute sessile reddish glands which soon disappear, purplish at first, soon grey- to red-brown; bark of twigs not flaking off. Stipules spinescent, mostly short, 2.5–8 mm. long and downwardly hooked, but some (especially on older twigs) elongate, 2–5.8 cm. long and nearly straight; “ant-galls” and other prickles absent. Leaves: pinnae 1–2 pairs, a small gland between the top (or only) pair; rhachis 0–8 mm. long; leaflets 3–9 pairs, mostly 2–5 mm. long, 0.75–1.5 mm. wide, glabrous or margins very sparsely and inconspicuously ciliolate; lateral nerves invisible beneath. Flowers bright yellow, in axillary pedunculate heads; involucel about ⅓–⅔-way up the peduncle. Calyx (except for puberulous lobes) and corolla glabrous outside. Pods dehiscent, linear, falcate, slightly constricted between the seeds, finely longitudinally or somewhat obliquely veined, glabrous, 6–15 cm. long, 0.5–0.6 cm. wide. Seeds olive or olive-brown, smooth, elliptic or elliptic-oblong, 6–7 mm. long, 3–3.5 mm. wide; areole 4.5–5 mm. long, 1.5–2 mm. wide.
