A tufted, erect perennial, 30–80 cm tall, generally rather slender. Tufts never very large, generally 10–15 cm diameter and with a fairly weak root system. Culms are densely branched at the base and often from the upper nodes. The stems are smooth and hairless but the nodes bear a ring of long (1.5 mm) erect white hairs. Leaves are flat, 8–15 cm long, 2–4 mm wide, often bluish-purple, typically without hairs although some forms are hairy. Leaf sheaths are round, close to the stem and may be almost as long as the internodes. Short ligules are membranous and ragged.
The inflorescences generally have 2–4 stalkless erect racemes with paired spikelets crowded into 2 ranks. The upper pairs, with a fertile sessile spikelet and a sterile pedicellate one, are all densely hairy, giving a silky-hairy appearance to the inflorescence. The lemmas of the upper sterile florets have a brownish, twisted hydroscopic awn about 2.5 cm long. Old culms often bear a remnant white tuft of seed head on the tip.