13. Arundinella nepalensis Trinius, Gram. Panic. 62. 1826.
石芒草 shi mang cao
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.
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.
Mountain grasslands, hill thickets; 500–1800 m. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hubei, SE Xizang, Yunnan [Bhutan, India, Myanmar, Nepal, Pakistan, Thailand, Vietnam; Africa, Australia].
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.