Swollen-stemmed tree, up to 3 m tall, stems 1-few, up to 300 mm diam., tapering towards tip, covered with spirally arranged tubercles, each tipped with 3 spines up to 70 mm long. Leaves in an apical rosette, ± lanceolate, 30-120 x 10-40 mm, stiffly pubescent, deciduous. Flowers in many, small cymes around apex. Corolla tubular, 25-50 x 6-10 mm, purple-brown around mouth, yellow below, lobes erect.
Succulent plant 1.5-2.5 m high; stem subcylindrical, simple or, rarely, branched, 10-30 cm in diameter at the base, tapering to 8-10 cm in diameter at the apex, closely tubercled throughout, each tubercle armed with a pair of long, straight, spreading persistent, stipular spines 3-7 cm long, subtending an abbreviated shoot with one or more short spines, up to 1.5 cm long. Leaves crowded at the apex, subsessile, obovate-oblong, oblong or oblanceolate, 8-12 cm long and 2-6 cm broad, grey-green, densely velvety on both sides with stellate hairs, apex obtuse to acute, base narrowly cuneate, margin crisped, petiole indistinct. Inflorescence a few-flowered, shortly peduncled cyme arising from the leaf axil and inflorescences clustered at the apex of the stem; bracts oblong, acute, 1-1.2 cm long; pedicels very short, villous; flowers yellow-green, suffused with deep red in the throat. Calyx 8-10 mm long, villous; lobes oblong, acute. Corolla tubular, 2.5-5 cm long, narrowly cylindrical at the base for 5-10 mm then expanding abruptly to 8-10 mm in diameter and increasing slightly towards the throat, loosely pubescent without and within; lobes oblong, rounded, 5-8 mm long. Stamens 5, lanceolate, sagittate, 6-7 mm long, united in a cone, subsessile, inserted at the apex of the narrow part of the tube. Disc cupular, obscurely lobed. Ovary of 2 free carpels; style filiform; stigma subcylindrical, with a basal rim, level with the centre of the anthers. Fruit of 2 follicular mericarps 2.5-4 cm long, tapering to the apex, densely grey pubescent. Seeds numerous, obovate, compressed, tuberced, 4 mm long with an apical coma of whitish hairs 8 mm long; cotyledons flat, shorter than the radicle; endosperm 0.