Acaulescent perennial. Leaves 1-2 m × 15 cm in large basal rosette fleshy, triangular in section, rosette dying after flowering and replaced by several small lateral rosettes; lamina rigid, leathery, glaucous, lanceolate, ± concave, outer often recurved from above middle, tipped by a conical hard stout dark brown or grey spine 2.5 cm long, margins with coarse grey-brown teeth to 5 mm long borne on horny prominences c. 4 cm apart. Panicle large, 1-2 m long, candelabra-like, terminal on stout ± woody scape 7-10 m high (produced rapidly at maturity of plant after 10-15 years' vegetative growth). Flowers many, yellow. Capsule to 5 cm long, oblong. Seeds black.