Arundinella setosa Trin.

This is a variable species with a bent awn flanked by two bristles on its lemma. The pedicels of the spikelets are most usually decorated with well-defined bristles or setae.

This is a variable species. The culms are slender or stout, and the leaves are occasionally hairy. The nodes are almost always glabrous, but can be bearded in very hairy specimens. The stiff bristles at the tips of the pedicels are usually obvious, but may sometimes be scanty or even absent. The length of the lateral bristles at the lemma tip is very variable. The bristles are frequently about as long as the column of the awn, but may be considerably shorter and in extreme cases almost absent. Forms without obvious bristles may be separated at varietal rank.

Rhizome short, hard; culms erect, tufted, 20-120 cm high, 1.5-5 mm across. Blade 10-40 cm long by 3-10 mm wide, usually covered with tubercle hairs; ligule membranous, about 0.5 mm long; sheath usually tubercle hairy, margin ciliated, shorter than the internode. Panicle slightly contracted, 10-30 cm long. Spikelets lanceolate, 5-7 mm long, hispid hairy at the basal part. Glumes ovate-lanceolate, subulate-lanceolate at the apex, nerves scabrous; lower glume 3-5-nerved, 3-5 mm long, about 3/5 as long as the spikelet; upper glume nearly as long as the spikelet, 5-nerved; lower lemma slightly shorter than the lower glume, glabrous, 5-nerved, staminate; anthers about 1.5 mm long; upper lemma about 2.5 mm long, scabrous, the midrib prolonged into a geniculate long awn; lateral nerves also prolonged into short awns; callus with soft hairs of about 0.7 mm long.

Perennial, tufted from a short rhizome with scaly buds. Culms erect or base geniculate, hard, (35–)60–180 cm tall, 1.5–4 mm in diam., sometimes branched, 3–7(–9)-noded, nodes glabrous. Leaf sheaths shorter than internodes, glabrous or infrequently tuberculate-hispid; leaf blades linear, 10–40(–70) cm × 3–9 mm, usually glabrous, sometimes tuberculate-hispid; ligule ca. 0.5 mm. Panicle open or somewhat contracted, 10–45 cm; central axis and branches scabrid; branches 5–20 cm, stiffly ascending or spreading, solitary or fasciculate, loosely spiculate; pedicels scabrid, apex usually with long stiff hairs. Spikelets 5–6.5 mm, green tinged purple; glumes glabrous or rarely setose, scaberulous along veins; lower glume 4.5–5.5 mm, 3 (–5)-veined; upper glume 5-veined; lower floret staminate or barren, shorter than glumes or equaling lower glume; upper floret 2.5–3 mm, lemma apex awned, awn flanked by 2 slender erect bristles; bristles mostly 1–2.5 mm; awn geniculate with brown twisted column, 6–10 mm; callus hairs 1/4–1/3 length of lemma. Fl. and fr. Aug–Dec.

Widely distributed in South-east Asia.

Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang [Bhutan, India, Indonesia, Malaysia, Myanmar, Nepal, New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; Australia].

Open forests, forest margins, grassy hillsides; 200–2300 m.