Rhizome stout, short. Leaves up to 250 x 12 cm, suberect, the basal part keeled on outer and canaliculate on inner surface; midrib, margins and base often reddish. Stem, including panicle, up to 400 cm. Flowers erect; pedicels 1-4 cm. Perianth 3-5 cm; outer lobes dark brownish-red, the inner yellow, somewhat recurved at apex. Stamens exceeding perianth; filaments red. Ovary acuminate. Capsule 7-9 x 2 cm, fusiform, trigonous, often curved, dark brown. Seeds 9 x 4 mm, compressed, elliptical, black.