Virgately branched shrub or tree up to 6 m high, armed with stout spines which are modified lateral shoots and which are often branched and bear leaves and inflor­escences; young branchlets pale greenish-yellow or yellowish-brown, becoming greyish- brown to grey or brown with age, subglabrous or occasionally finely pubescent when young. Leaves reduced to green pinnae-rhachillae (2)4-15 cm long, terete or subterete, slightly grooved on the upper surface, with up to 15 nodes but no leaflets or occasionally with minute inconspicuous scale-like linear or oblanceolate opposite leaflets up to 1,5 x 0,5 mm. Stipules inconspicuous, not spine-scent. Racemes lax, up to 18 cm long; bracts up to 1,5 mm long, ± ovate, soon deciduous. Flowers yellow, on pedicels 3-10 mm long (excluding the elongate lower part of the hypanthium). Receptacle consisting of a disc up to 3 mm in diameter and a lower elongate part up to 10 mm long which simulates the pedicel; the disc usually remaining in fruit to form a small collar. Sepals 5-8 mm long, narrowly-ovate to + oblong, narrowly imbricate, becoming reflexed in flower, subglabrous or with short scattered hairs. Petals 7-12 mm long, the upper one larger than the others, with a distinct claw and a ± reniform lamina; the other petals ovate-lanceolate. Stamens up to 12 mm long, filaments densely pubescent below; anthers 1-1,7 mm long. Ovary glabrous or with few scattered hairs, especially on the margins. Pods brown, (3,5)5-13 cm long, 0,6-0,95 cm wide, linear, straight or curved and sometimes ± falcate, attenuate at both ends, flattened, often somewhat constricted between the seeds, glabrous, longitudinally venose, indehiscent or perhaps very tardily dehiscent. Seeds 7-9,5 X 5-6 x 2-3 mm, oblong, elongated longitudinally in the pods, mottled, light brown with dark brown markings, smooth. Fig. 21.