Description from Flora of China
Festuca sylvatica Hudson, Fl. Angl. 1: 38. 1762; Agropyron sylvaticum (Hudson) Chevallier; Brachypodium formosanum Hayata; B. hayatanum Honda; B. kelungense Honda; B. manshuricum Kitagawa; B. sylvaticum var. breviglume Keng ex P. C. Keng; B. sylvaticum var. gracile (Weigel) Keng; B. sylvaticum var. kelungense (Honda) C. C. Hsu; B. sylvaticum subsp. luzoniense Hackel; B. sylvaticum var. luzoniense (Hackel) H. Hara; Brevipodium sylvaticum (Hudson) A. Löve & D. Löve; Bromus gracilis Weigel; B. sylvaticus (Hudson) Lyons; Triticum sylvaticum (Hudson) Moench.
Perennial. Culms loosely tufted, erect, slender, (20–)40–90 cm tall, 3–7-noded. Leaf sheaths sparsely to densely pilose, or sometimes glabrous; leaf blades linear, usually flat, mid or dark green, 8–35 cm, 3–9 mm wide, glabrous to pilose on one or both surfaces, or hispid along veins; ligule 0.5–2 mm. Raceme 8–12 cm, suberect or nodding, spikelets 3–9; pedicels less than 2 mm. Spikelets 1.5–3 cm, subterete, florets 5–12; glumes lanceolate, glabrous, pubescent or scabrous on veins, apex acuminate or midvein extended into awn-point, lower glume 3–10 mm, 3–7-veined, upper glume 5–14 mm, 5–9-veined; lemmas 7–14 mm, pilose or hispid on margins and upper back, sometimes sparsely, or glabrous throughout; awn 5–14 mm. Anthers 2.5–5 mm. Fl. and fr. Jul–Sep.
This species is the most widespread in the genus and is extremely polymorphic throughout its range. This has resulted in the description of many infraspecific variants. These are usually based on differences in pubescence of the vegetative parts and spikelets, but these characters are extremely plastic. The relative size of the spikelet parts is also variable and of doubtful taxonomic significance.
The name Brachypodium sylvaticum var. kelungense is based on specimens from Taiwan with mucronate glumes, but these are found throughout the range of the species. Spikelets with acute and mucronate glumes may even occur in the same raceme. The name B. sylvaticum var. gracile has been applied to small forms in China, but it is based on a type from Germany, and such specimens are probably only depauperate. Thus, while phenotypic variants may appear very different, the characters on which they are based occur in all combinations throughout the range of the species, making the recognition of infraspecific taxa very uncertain. No detailed comparison has ever been made between the European and E Asian populations.
In tropical SE Asia Brachypodium sylvaticum occurs only on mountains.
Mountain slopes, understory of forests. Anhui, Gansu, Guizhou, Jiangsu, Liaoning, Qinghai, Shaanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang [Bhutan, N India, Indonesia, Japan, Kyrgyzstan, Nepal, Pakistan, Philippines, Russia, Tajikistan, Turkmenistan, Uzbekistan; N Africa, SW Asia, Europe].