Perennial reed, with creeping rhizomes. Culms erect, 1.5-3(6) m high. Leaf-blades 20-60 cm (or more) long and 8-32 mm wide, glabrous, smooth beneath, the tips filiform and flexuous (sometimes stiff and pungent, see below). Panicle 20-30(-50) cm long and 6-10(-15) cm wide, the lowest node usually few-branched, some of the branches bearing spikelets nearly to their base. Spikelets 12-18 mm long, the rhachilla-hairs 6-10 mm long, copious, silky; lower glume 3-4.5 mm long; upper glume lanceolate, 5-9 mm long, sharply acute, usually apiculate; lowest lemma linear lanceolate to linear-oblong, 8-15 mm long; fertile lemmas very narrowly lanceolate, 9-13 mm long.