Description from Flora of China
Calamagrostis pulchella Grisebach, Nachr. Königl. Ges. Wiss. Georg-Augusts-Univ. 3: 78. 1868, not Reichenbach (1830); C. lahulensis Singh; C. megalantha (Keng ex P. C. Keng) P. C. Keng; Deyeuxia gyirongensis P. C. Kuo & S. L. Lu; D. megalantha Keng ex P. C. Keng; D. pulchella var. laxa P. C. Kuo & S. L. Lu.
Perennial, densely tufted, rhizomatous; rhizomes elongate, slender. Culms erect, 10–40 cm tall, 1–1.5 mm in diam., scabrid below panicle, 2–3-noded. Leaf sheaths scabrid; leaf blades flat or involute when dry, 2–13 cm, 1–4 mm wide, scabrid, apex acute; ligule 2–4 mm, lacerate. Panicle dense, spikelike, lanceolate-oblong in outline, or sometimes laxer, 3–7(–13) × 0.8–1.5(–5) cm; branches 1–5 cm, scabrid. Spikelets 3–5(–6) mm, dark purple; glumes lanceolate, subequal or lower glume slightly shorter than upper, lower glume 1-veined, upper glume 3-veined, scabrid, apex acuminate; callus hairs ca. 1/3 length of lemma; lemma 3–4.5 mm, papery, hyaline at margins and apex, sometimes scabrid; apex irregularly 4-toothed; awn arising from upper 1/3 of lemma back or above, 1–2.5(–6) mm, straight or slightly curved; palea ca. 2/3 as long as lemma; rachilla conspicuously penicillate, 1.5–2 mm, including hairs up to 5 mm. Anthers 1.4–2.3 mm. Fl. Jul–Aug.
This is a polymorphic species, varying especially in the compactness of the panicle and the length and position of the awn on the lemma back. Looser-panicled forms (var. laxa) are somewhat intermediate with Deyeuxia scabrescens. These two species are closely related, and hybridization is possibly occurring.
The spikelets in the type of Deyeuxia megalantha are enlarged due to nematode infection.
Alpine meadows, in woodlands, among bushes; 2700–5200 m. Sichuan, Xizang, Yunnan [Bhutan, N India, Kashmir, Nepal].