River Grass

This is a widespread species showing much variation in height and vigor, hairiness of the vegetative parts, and compactness of the panicle. The many-noded culms are characteristic, with silky-pubescent nodes and a banded effect from green internodes alternating with yellowish leaf sheaths, together with a panicle of numerous whorled branches.

Arundinella pilaxilis is based on a variant with tuberculate-hispid culms. Arundinella pilomarginata is based on a specimen from Yunnan with the lower glume ciliate on one or both margins in some of the spikelets.

Perennial, tufted with short scaly rhizomes. Culms erect, slender to stout, 0.9–2(–3) m tall, 2–7 mm in diam., simple or branched, internodes usually glabrous, 6–8-noded, nodes appressed silky pubescent. Leaf sheaths usually glabrous, occasionally tuberculate-pilose, usually bearded at mouth; leaf blades linear-lanceolate, stiff, flat or convolute, 10–50 cm × 5–18 mm, glabrous or thinly to densely tuberculate-pilose, apex long acuminate; ligule 0.3–0.5 mm. Panicle open or loosely contracted, 10–50 cm; central axis scaberulous or almost smooth; branches numerous, slender, 7–20 cm, subverticillate, simple or lowest branched, loosely spiculate; pedicels smooth or scabrid. Spikelets (3.5–)4–5.5 mm; pale green to dark purple; glumes usually glabrous; lower glume 3–3.5 mm, strongly 3-veined; upper glume 4.5–5.5 mm, faintly 5-veined; lower floret staminate or barren, equaling or longer than lower glume; upper floret 2–2.5 mm, lemma awned; awn geniculate with brown twisted column, 3.5–5 mm; callus hairs 1/4–1/3 length of lemma. Fl. and fr. Aug–Nov.

Tufted perennial with scaly rhizomes; culms 60-180 cm high, erect. Leaf-blades linear or convolute, 8-30 cm long, 3-10 mm wide, stiff, scaberulous, glabrous or hirsute. Panicle oblong, open or contracted, 10-40 cm long, the branches subsecund and densely spiculate. Spikelets lanceolate, 4-6 mm long, glabrous; lower glume ovate 3-5 mm long, acutely or setaceously acuminate; upper glume narrowly ovate, acuminate with an obtuse tip; lower lemma 34 mm long, obtuse; upper lemma ovate, 2-2.5 mm long, emarginate with a geniculate awn 4-6 mm long; callus bearded with hairs 0.5-1 mm long; palea with door-like flaps.

E. Himalaya (Nepal, Sikkim), India, S.E. Asia, China.

Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hubei, SE Xizang, Yunnan [Bhutan, India, Myanmar, Nepal, Pakistan, Thailand, Vietnam; Africa, Australia].

Distribution: Pakistan (Punjab, N.W.F.P. & Kashmir); tropical and South Africa; Madagascar; India to China and Australia.

500-2500 m

Mountain grasslands, hill thickets; 500–1800 m.

Acratherum miliaceum Link; Arundinella glabra Nees ex Hooker & Arnott; A. miliacea (Link) Nees; A. pilaxilis B. S. Sun & Z. H. Hu; A. pilomarginata B. S. Sun; A. virgata Janowski.