Description from Flora of China
Trisetum sibiricum Ruprecht var. umbratile Kitagawa, Rep. Inst. Sci. Res. Manchoukuo 4: 77. 1940; T. sibiricum subsp. umbratile (Kitagawa) Tzvelev.
Culms erect, slender, 70–90 cm tall, glabrous. Leaf sheaths equaling or shorter than internodes, glabrous, outer margin ciliate at mouth, margins closed near base; leaf blades linear, 8–30 cm, 2–7 mm wide, scabrid; ligule 1–2 mm. Panicle lax, broadly lanceolate in outline, up to 22 cm, green; branches capillary, smooth in lower part, upper part scabrid. Spikelets 4–5(–6) mm, florets 1 or 2; rachilla hairs ca. 1.4 mm; glumes unequal, lower glume oblong-lanceolate, 2.5–4 mm, upper glume oblong, 4–5 mm; lemmas 4.5–5.5 mm, scabrid-papillose, awned from above middle, apex 2-toothed, teeth ca. 1.5 mm, acute; awn up to 6.5 mm, straight or almost so, not twisted; palea keels indistinctly scaberulous. Anthers ca. 2 mm. Fl. and fr. Jul–Sep.
This is a locally distributed variant of Trisetum sibiricum with small spikelets and almost straight awns.
Marshy meadows and in forest. Heilongjiang, Jilin, Liaoning, Nei Mongol (Yakeshi) [Korea, Russia (Ussuri)].