Description from Flora of China
Perennials, densely tufted, not rhizomatous; shoots intravaginal. Culms 30–65 cm tall, ca. 1 mm in diam., smooth, nodes 2 or 3, 1–3 exserted, uppermost node to 1/3–1/2 way up culm. Leaf sheaths narrowly keeled, smooth or sparsely scabrid, glabrous, lowermost loose, short, moderately firm, becoming papery, 4.5–12 cm, 1.3–1.8 × as long as blade, uppermost closed for 3/7–4/7 of length; blades flat or folded with margins inrolled or not, thin to moderately thin, 3–11 cm × 1–2 mm wide, uppermost 3–7 cm, abaxially smooth except the upper keel scabrid, adaxial surface and margins scabrid, of tillers 4–20 cm, adaxially strigose in some; ligules 2–4.1 mm, abaxially smooth, apex obtuse to acute, of tillers ca. 0.5 mm, abaxially scabrid, apex truncate, scabrid, collars of lower and tiller leaves smooth, glabrous, or margins with a few ciliate hairs. Panicle open, lax, narrowly triangular, well exserted, diffuse, 5.5–14 × 3–8 cm, longest internodes 2–3.5 cm; branches spreading, flexuous, 2 per node, slender, round, smooth (or with a few hooks), longest 3–7.5 cm with 3–11 spikelets in distal 1/3; flowers female, perfect, or male. Spikelets elliptic, 3.5–6 mm, florets 2(or 3); vivipary absent; rachilla internodes to 1.2 mm, scabrid or densely hispidulous; glumes unequal, ovate to oblong, surfaces minutely punctate with purple papillae, membranous to very thinly papery, keels scabrid above, lower glume 2.3–3.5 mm, 1- to faintly 3-veined, upper glume 2.7–4.5 mm, faintly 3-veined, broadest above middle, 1.5–2 × broader than lower one, shorter than 1st lemma by 1–2 mm; lemmas thinly papery, 3.5–5.2 mm, apex narrowly membranous, acute, keel villous for 1/2 of length, marginal veins to 1/4, intermediate veins moderately prominent, area between veins proximally minutely bumpy, scabrid or crisply pilulose, distally smooth or sparsely scabrid, minutely bumpy; callus webbed; palea proximally densely scabrid to hispidulous between keel, keels scabrid. Anthers ca. 2 mm or vestigial. Fl. and fr. Jun–Aug.
The type of Poa nubigena differs from P. mairei in its longer ligules, smooth, glabrous collars, presence of numerous female flowers, and slightly thinner leaf blades, branches, and glumes. The species approaches P. pagophila, but is generally taller and occurs at lower elevations.
* Meadows on slopes, river bank rocky grassy places, ravines; 2200–3700 m. W Sichuan, E Xizang, NW Yunnan.