Description from Flora of China
Agrostis infirma Buse var. fukuyamae (Ohwi) Veldkamp; A. rigidula Steudel subsp. fukuyamae (Ohwi) T. Koyama; A. rigidula var. fukuyamae (Ohwi) Veldkamp.
Perennial, tufted. Culms erect, 15–20 cm tall, 0.5–1 mm in diam., 2-noded. Leaf sheaths longer than internodes, smooth; leaf blades narrowly linear to setaceous, folded, 5–10 cm × 0.6–1 mm (when folded), abaxial surface smooth or scaberulous, adaxial surface scabrid; ligule 0.8–1.5 mm, apex rounded or truncate. Panicle contracted when young, later open, narrowly ovate in outline, 7–10 cm; branches 3–4 per node, ascending to spreading, longest 3.5–6 cm, almost smooth, bearing spikelets from near base. Spikelets 1.5–2 mm, purplish green; glumes lanceolate-oblong, equal, keel scaberulous toward apex, apex acute; callus hairs 0.2–0.3 mm; lemma more than 3/4 spikelet length, awnless, midvein terminating near middle of back, apex broadly obtuse; palea 0.6–0.8 mm, slightly less to slightly more than 1/2 lemma length. Anthers 0.7–1 mm. Fl. Jul.
This species is perhaps no more than a local, high-altitude variant of Agrostis infirma, differing by its smaller spikelets with a relatively longer lemma and longer palea.
* Exposed rocks near mountain summits. Taiwan.