Plants female or bisexual. Culms to 4 m high, normally less than twice the height of basal leaves, nodes glabrous, mostly concealed by leaf-sheaths; leaves dull bluish- or grey-green, glabrous; sheath usually glabrous; blade turned from shortly above the sheath (so that the scabrous lower surface is uppermost), flat, narrowly tapered toward the tips, coarsely scabrous on margins and nerves on lower surface, midrib prominently thickened, to 1.8 m long and 2 cm wide; ligule a dense row of fine, silky hairs to 4 mm long. Inflorescence a dense, plume-like panicle 25–100 cm long, white, yellowish or purplish. Spikelets 10–17 mm long, veins of glume and rachilla segments unpigmented, spikelets 5–7-flowered; glumes hyaline, narrow-acuminate, 10–15 mm long, subequal; florets narrow-acuminate, about equal to glumes or slightly shorter; lemma narrowly tapered with fine, awn-like apices, 7–13 mm long overall, hyaline, smooth, glabrous or with a few long hairs in bisexual flowers, plumose in female flowers; palea 3–5 mm long, hyaline, glabrous. Flowers Mar.–May.