5. Arundinella hirta (Thunberg) Tanaka, Bull. Sci. Fak. Terk. Kjusu Imp. Univ. 1: 196, 208. 1925.
毛秆野古草 mao gan ye gu cao
Perennial, loosely tufted with stout scaly rhizomes. Culms erect, 60–150 cm tall, 2–5 mm in diam., glabrous or less often tuberculate-hispid or densely pilose, nodes glabrous or bearded. Leaf sheaths usually tuberculate-hispid on margins, often thinly hispid throughout, less often densely pilose or completely glabrous; leaf blades broadly linear, 10–50 cm × (4–)7–15 mm, tuberculate-setose on margins only, or thinly hispid to densely pilose on both surfaces, or glabrous, apex long-acuminate; ligule 0.2–0.7 mm. Panicle contracted, narrowly elliptic-oblong in outline, 8–45 cm; central axis scabrid to setose; branches 5–20 cm, ascending, lower often with branchlets, densely spiculate; pedicels scabrid. Spikelets 3–4.8 mm, plump; glumes glabrous or rarely hispid, scabrid along prominent veins; lower glume 2.5–4 mm, 3(–5)-veined; upper glume 5–7-veined; lower floret subequal to spikelet; upper floret 2.5–3.5 mm, lemma apex acute to shortly mucronate, callus hairs nearly 1/2 length of lemma. Fl. and fr. Jul–Oct. 2n = 28, 34, 36, 56.
Grassy mountain slopes, river banks, roadsides, field margins; 100–1500 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Shaanxi, Shandong, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, Korea, E Russia].
This polymorphic species exhibits much minor variation in the hairiness of culms, nodes, and leaves, and many infraspecific names have been applied. The name Arundinella anomala has been used in the past for plants with glabrous culms and glabrous to moderately hairy leaf sheaths, whereas plants with densely hairy culms and leaf sheaths have been referred to A. hirta. However, the protologue of A. hirta states that the culms are glabrous. In practice, the different combinations of hairiness of culms, nodes, and leaves make a subdivision into two entities impracticable on this character, even at infraspecific rank. Rarely variants occur with setose spikelets, and these can be recognized at varietal rank.