Description from Flora of China
Avena altior Hitchcock, Proc. Biol. Soc. Washington 43: 96. 1930; Avenastrum trisetoides Kitagawa.
Perennial, shortly rhizomatous. Culms erect from shortly decumbent base, solitary or few, 1–1.2 m tall, 3–4-noded, nodes pubescent. Leaf sheaths usually shorter than internodes, densely puberulous or basal sheaths glabrous; leaf blades broadly linear, flat, ca. 15 cm, 3–8 mm wide, abaxial surface pubescent, scabrid, adaxial surface pilose, or sometimes glabrous; ligule truncate or erose, 1–2 mm, margin ciliolate. Panicle loose, lanceolate to oblong in outline, 10–20 cm; branches 4–6 per node, ascending, slender, often flexuous, up to 7 cm, scabrid, lower part bare, upper part bearing 1–3 spikelets. Spikelets 0.8–1.4 cm, yellowish green or purplish green, florets 3–4(–5); rachilla hairs 2–3 mm; glumes thinly membranous, lower glume 4–7 mm, 1-veined, upper glume 8–11 mm, 3-veined; lemmas leathery, lowest ca. 9 mm, 5–7-veined, smooth; awn 1–1.5 cm, geniculate, column twisted, terete; palea keels ciliolate. Anthers 4–5 mm. Fl. and fr. Jul–Aug.
This is an element of the Helictotrichon junghuhnii complex, mainly distinguished by the hairy culm nodes.
* Moist grassy slopes, under shrubs, Picea forests; 2000–4000 m. Gansu, Heilongjiang, Ningxia, Qinghai, Sichuan.