Similar in habit to A. ferox. Lvs pinnate (2-(3) pairs,) up to c. 8 dm. long; sheaths thick and coriac., c. 5 cm. wide at base, narrowing to 3 cm.; stipules simple, ± (10)-15-(25) cm. long, pungent. Petioles thick, coriac., ribbed; margins cartilaginous, serrulate; internodes short. Primary pinnae up to c. 4 dm. × 2-(3) cm., very coriac., finely striate, midrib obscure, us. strongly curved, lanceolate, margins serrulate, apex. pungent. Stems ± 1·5 m. tall, stout, strongly grooved, flowering through most of their length; infl. broad. Bracts ∞, the lower empty, or with ill-developed umbels. Bract-sheath ± 55 × 35 mm.; stipules up to 75 × 7 mm., distinctly ribbed; lamina simple, lanceolate, up to c. 185 × 15 mm., narrowing from widest part ± ⅔ way. Umbels ± = bract-sheaths; rays ∞, up to 3 cm. long. Umbellules of male plants on long slender rays, of females on shorter rays. Involucral bracts lanceolate. Fr. c. 4 mm. long; mericarps with 2 or 3 broad wings.

2n = 22