Lasiagrostis tremula Ruprecht; Ptilagrostis purpurea (Grisebach) Roshevitz; Stipa purpurea subsp. arenosa (Tzvelev) D. F. Cui; S. purpurea var. arenosa Tzvelev; S. pilgeriana K. S. Hao.

Perennial, densely tufted. Culms 20–45 cm tall, 1–2-noded. Basal leaves 1/2 length of culms; leaf sheaths smooth, longer than internodes; leaf blades acicular, convolute, outer surface smooth or scabrid; ligule of basal leaves ca. 1 mm, obtuse, ciliate, of culm leaves lanceolate, 3–6 mm, decurrent and adnate to margins of leaf sheath. Panicle open, up to 15 cm, base enclosed in elongate purple uppermost leaf sheath, spikelets few; branches 3–6 cm, capillary, flexuous. Spikelets purple; glumes lanceolate, 1.3–2.5 cm, apex acuminate into 2–3 mm awn point; callus pungent, 1.5–2.2 mm; lemma 8–12 mm, back softly pubescent, apex without ring of hairs; awn deciduous, 6–9 cm, plumose throughout, hairs 2–3 mm, 2-geniculate, column 1.5–1.8 cm to first bend, 0.7–1 cm to second bend, bristle 4.5–7 cm. Fl. and fr. Jun–Oct.

This species provides forage in mountain areas. At high altitudes it often occurs in Kobresia pygmaea turf.

Stony slopes, valley silt, sand or gravel flats; 1900–5200 m. Gansu, Qinghai, Sichuan, Xinjiang, Xizang [Kashmir, Kyrgyzstan (Pamirs), Tajikistan (Tian Shan)].