Perennial, tufted, old basal sheaths becoming fibrous. Culms wiry, 30–80 cm tall, 0.6–1.4 mm in diam. Leaf sheaths smooth; leaf blades usually rolled, 7–15 cm × 2–4(–6) mm, smooth, abaxial surface green, adaxial surface grayish green; ligule 0.7–1 mm, ca. 1.5 mm lobe on side opposite blade. Panicle linear, 10–25 cm; branches clustered at nodes, erect, flexuous, 1–2 cm, distant or slightly overlapping, bearing 1–5 spikelets. Spikelets ovate-oblong, 3.5–6.5 mm, purple or straw-colored, fertile florets 2 or 3, terminal sterile lemmas gathered into globular cluster; glumes unequal, much shorter than florets, lower glume ovate, 1.5–3.5 mm, 3–5-veined, upper glume broadly lanceolate, 2.5–4.2 mm, 5-veined, both acute; lemmas elliptic-oblong, lowest 3–5 mm, herbaceous, 7-veined, granular-scabrid, usually sparsely hirsute at middle back with stiff, 0.3–0.6 mm hairs along veins, rarely glabrous, apex obtuse or acute; palea as long as lemma, keels scaberulous. Anthers 1–1.8 mm. Fl. and fr. May–Jul.