23. Agrostis flaccida Hackel, Bull. Herb. Boissier. 7: 649. 1899.
柔软剪股颖 rou ruan jian gu ying
Perennial, tufted, shortly rhizomatous. Culms erect or geniculate at base, slender, 15–30(–50) cm tall, ca. 1 mm in diam., 3-noded. Leaf sheaths smooth; leaf blades narrowly linear, weakly rolled or infrequently flat, soft, 5–10 cm × 0.5–2 mm, smooth, uppermost culm blade elongate, widely divergent from culm; ligule 1–2 mm, apex obtuse. Panicle open, diffuse, narrowly ovate in outline, 4–8 cm; branches 2–5 per node, spreading, capillary, 5–7 cm, smooth or almost so, bare in lower half. Spikelets 2.5–3 mm, purple or purplish green; glumes lanceolate, slightly unequal, keel scabrid, apex acuminate; callus hairs 0.2–0.5 mm; lemma 2/3–3/4 spikelet length, indistinctly granular-scaberulous, awned from lower 1/4–1/3 of back, lateral veins sometimes minutely exserted, apex truncate-denticulate; awn weakly geniculate, 3–5 mm; palea ca. 0.25 mm. Anthers 1–1.6 mm. Fl. and fr. Jul–Aug. 2n = 14.
Rocky slopes, open forest; 1500–2300 m. E Jilin, Liaoning [Japan, Korea, Russia (Kamchatka, Kuril Islands, Sakhalin)].
Agrostis flaccida is distinguished from other members of the A. vinealis complex mainly by its smooth leaf blades and panicle branches (see the comment under the next species).