Shrub to c. 2 m high with stout, soft-wooded, hollow stems and suckering root system. Lvs to 50-(100) cm long, glaucous below. Stipules fused and sheathing, 7-15 cm long, ovate, cuspidate. Rachis winged. Leaflets 11-21, sessile, 8-15 × 3.5-7.5 cm, gradually tapering towards apex, ± folded, regularly and deeply serrate with teeth c. 1 cm long; basal pair smaller. Racemes dense, to c. 40 cm long, puberulent. Pedicels 1-2.5 cm long, dark red, with short glandular hairs. Bracts ovate or narrow-ovate, to 4 cm long, reddish brown, short-acuminate. Fls foetid, dark reddish brown. Anterior calyx segment much < others, gibbous, with short glandular hairs. Posterior calyx segments 2-3 cm long, ovate, with short glandular hairs. Petals much < calyx. Stamens c. 2 cm long. Style 1.5-2 cm long. Capsule 2.5-5 cm long, papery, acutely angled. Seeds 5-6 mm long, ± broad-ellipsoid, keeled, shining black.