Description from Flora of China
Poa flavida Keng ex L. Liu; P. mongolica (Rendle) Keng ex Shan Chen; P. nemoralis Linnaeus var. mongolica Rendle; P. pseudonemoralis Skvortsov (1954), not Schur (1866); P. pseudopalustris Keng ex Shan Chen, nom. illeg. superfl.; P. skvortzovii Probatova; P. vaginans Keng.
Culms tufted, (40–)60–110(–120) cm tall, usually robust, erect, scabrid, nodes 3; upper internode elongated, to ca. 80 cm, ca. 2.5 mm thick. Leaf sheath scabrid, slightly longer than leaf blade; leaf blade flat, scabrid, 2–4 mm wide, ligule membranous, (0.2–)0.5–3.5 mm. Panicle narrow, 10–23 × (1–)2–4(–6) cm; branches straight, lower part naked, upper part with 4–6 spikelets. Spikelets 3.5–8 mm, florets 2–5(–6); rachilla pubescent, prickled, warty or glabrous; glumes subequal, lanceolate, apex slightly acuminate, 2.5–3.5(–5) mm; lemma broadly lanceolate, 3–4 mm; keel scabrid, lower half and lower 1/3 of marginal veins villous; callus sparsely villous; palea keels, scabrid or shortly pubescent, area between glabrous. Anthers 1.4–2 mm. Fl. Aug. 2n = 28, 35, 42.
The types of Poa flavida and, probably, P. nemoralis var. mongolica show these taxa to be less robust forms of P. alta. The type of P. skvortsovii (P. pseudonemoralis Skvortsov, not Schur; P. pseudopalustris) looks like the most common form of P. alta. According to the protologue, P. vaginans differs from P. flavida in having culms with 4 or 5 nodes, in having a panicle with 2 or 3 branches at the lowest node, in spikelet size, and in the lemma being pubescent proximally between the veins; however, the type of P. vaginans has the lemma smooth between the veins and culms with only 2 or 3 nodes, and it does not differ in the number of panicle branches or in spikelet size. All the species of this group should be treated as P. alta.
Mountain tops, open grassy slopes; ca. 2500 m. Heilongjiang, Jilin, Liaoning, Nei Mongol, Shaanxi, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan [Japan, Mongolia, Russia].