Shrub 0.5–1.5 m. high, very flat-topped, spreading to 3.6 m. Young branchlets densely hairy (hairs up to 0.5(–0.75) mm. long, yellowish when young), slowly glabrescent, going pale to deep brown later; epidermis not or scarcely flaking or peeling; lenticels pale, dot-like. Stipules spinescent, straight, on mature shoots (2–)3.5–6.5 cm. long (? more); “ant-galls” and other prickles absent. Leaves: rhachis (1.5–)4–7.5(–12) cm. long, densely pubescent; pinnae (4–)8–14(–23) pairs; leaflets 8–30 pairs, 2.5–5 mm. long, 0.5–1.25 mm. wide, ciliate, paler beneath than above. Flowers white, in heads on axillary, tomentose or densely pubescent, eglandular peduncles 1.5–3 cm. long; involucel basal or in lower half of peduncle. Calyx 3–3.75 mm. long. Corolla 4–5.5 mm. long, lobes densely white-tomentose outside. Pods straight or nearly so, about 10–22 cm. long and 0.9–1.6 cm. wide, attenuate at both ends, densely grey-velvety, cylindrical when ripe. Seeds large, blackish, ellipsoid, about 12 mm. long and 10 mm. wide; areole about 10 × 5 mm.
