Robust rhizomatous perennial to 6 m high, emergent aquatic.
Leaves with ligule a densely ciliate, membranous rim with hairs c. 1 mm long, sometimes scattered with hairs to 10 mm long on upper leaves; blade to 3.5 cm wide, glabrous.
Inflorescence 15–30 cm long, 5–20 cm wide, hairy, green to purplish brown and silvery white at maturity; axils of branchlets with hairs to 7 mm long. Spikelets of 4–8 florets, the lowest 1 or 2 male, the others bisexual; rachilla with hairs c. 12 mm long. Glumes mucronate or aristate, glabrous, lower 3–5 mm long, upper 6–8 mm long. Male lemmas c. 12 mm long, glabrous; palea 3–4 mm long. Bisexual lemmas acuminate, glabrous, 10–16 mm long, upper lemmas successively smaller; callus with hairs 10–12 mm long; palea 3–4 mm long.