Description from Flora of China
Calamagrostis scabrescens Grisebach, Nachr. Königl. Ges. Wiss. Georg-Augusts-Univ. 3: 79. 1868; C. scabrescens var. humilis Grisebach; Deyeuxia scabrescens var. humilis (Grisebach) J. D. Hooker; D. sikangensis Keng.
Perennial, tufted, shortly rhizomatous. Culms erect, 60–150 cm tall, 1–4 mm in diam., scabrid or almost smooth below panicle, 2–4-noded. Leaf sheaths smooth or scabrid; leaf blades erect, convolute or flat, stiff, 10–45 cm, 2–8 mm wide, scabrid; ligule 2–6 mm, obtuse. Panicle loosely contracted, narrowly lanceolate in outline, 6–25 × 1.5–4 cm; branches several per node, erect or ascending, scabrid; pedicels very scabrid. Spikelets 4–6 mm, yellowish green or purple; glumes oblong-lanceolate, subequal or lower glume slightly longer than upper, densely scabrid, lower glume ciliolate along margin, 1-veined, upper glume 3-veined at base, apex sharply acuminate; callus hairs ca. 1/3 lemma length; lemma 3.5–5 mm, scabrid, apex denticulate; awn arising from or above middle of lemma, 5–9 mm, weakly geniculate; palea 2/3–3/4 as long as lemma; rachilla conspicuously penicillate, 1.5–2 mm, including hairs 3–4 mm. Anthers 2–3 mm. Fl. and fr. Jul–Oct.
This is one of the more common species of Deyeuxia in China, occurring mainly at higher altitudes in the southwest. Deyeuxia pyramidalis is a closely related species with a similarly robust habit, but this occurs mainly at lower altitudes in eastern and northern areas. Deyeuxia scabrescens is very variable, but recognizable by its very scabrid panicle and spikelets, conspicuously penicillate rachilla, but short callus hairs, and awn arising from the upper part of the lemma back.
Deyeuxia scabrescens intergrades with D. pulchella, and intermediates occur causing problems for identification. Deyeuxia scabres-cens var. humilis is based on a short plant with an almost straight awn, which is probably an introgression product of these two species.
The name "Deyeuxia dispar L. Liou" (Vasc. Pl. Hengduan Mts. 2: 2237. 1994) belongs here, but was not validly published because no Latin description was provided. The specimen indicated as the holotype has some enlarged spikelets, typical of nematode infection.
Grassy slopes, among shrubs, in woods; 2000–4600 m. Gansu, Hubei, Qinghai, Shaanxi, Sichuan, Xizang, Yunnan [Bhutan, India, Kashmir, Myanmar, Nepal, Pakistan].