Description from Flora of China
Perennial, densely tufted. Culms erect, slender, hard, 20–50 cm tall, 0.5–1.5 mm in diam., 7–13-noded, nodes glabrous. Leaf sheaths shorter than internodes, densely tuberculate-hispid, glabrescent; leaf blades linear, 3–12 cm × 1–2 mm, with tubercle-based hairs on both surfaces, glabrescent; ligule 0.3–0.5 mm. Panicle sparse, 4–8 cm; central axis and branches scaberulous; branches few, 2.5–5 cm, laxly ascending; pedicels with a few long stiff hairs at apex. Spikelets 4.5–5.5 mm, green tinged purple; glumes setose along veins; lower glume 3.5–5 mm, 3-veined; upper glume 5-veined; lower floret staminate or barren, shorter than glumes; upper floret ca. 2 mm, lemma apex awned, awn flanked by 2 slender erect bristles; bristles 1.5–1.8 mm; awn geniculate, 4.5–5.5 mm; callus hairs hairs 1/3 length of lemma. Fl. and fr. Aug–Dec.
This is a slender species close to Arundinella setosa, found in the same riverine habitats as A. fluviatilis and A. rupestris, but differing from the latter two by the lateral bristles flanking the geniculate awn on the upper lemma.
* River banks among rocks, floodlands; ca. 500 m. Yunnan (Jinghong).