15. Agrostis infirma Buse, Pl. Jungh., Gramineae, preprint. 2. 1854.
玉山剪股颖 yu shan jian gu ying
Agrostis flaccida Hackel var. morrisonensis (Hayata) Honda; A. macilenta Keng; A. morrisonensis Hayata; A. rigidula Steudel; A. shandongensis F. Z. Li; A. sozanensis Hayata var. exaristata Handel-Mazzetti; A. wulingensis Honda.
Perennial, densely tufted. Culms slender, erect or geniculate at base, 20–100 cm tall, 0.5–2.5 mm in diam., 2–3-noded. Leaves mainly basal, leaf sheaths smooth; leaf blades often involute and acicular or narrowly linear and flat, 4–14 cm × 0.3–5 mm, smooth or slightly scaberulous; ligule of culm blades 2.25–2.75 mm, apex rounded. Panicle open or slightly contracted, elliptic in outline, 8–14(–25) cm; branches 4–6 per node, laxly ascending, 3–8(–10) cm, smooth, lower part bare. Spikelets 2–2.8 mm, purplish green; glumes lanceolate, unequal with lower longer, keel scabrid, apex acute; callus glabrous or almost so; lemma 3/4 spikelet length, awnless or rarely mucronate above middle, apex obtuse; palea 0.15–0.35 mm, less than 0.2 lemma length. Anthers 0.5–1 mm. Fr. Nov.
Mountains; 2600–4000 m. Heilongjiang, Hunan, Shandong, Taiwan, Yunnan [Indonesia, New Guinea, Philippines].
Agrostis infirma is a variable species widespread in SE Asia. Agrostis sozanensis is very similar, but has awned spikelets.