21b. Poa pratensis subsp. angustifolia (Linnaeus) Lejeun, Comp. Fl. Belg. 82. 1828.
细叶早熟禾 xi ye zao shu he
Poa angustifolia Linnaeus, Sp. Pl 1: 67. 1753; P. pratensis var. angustifolia (Linnaeus) Smith.
Plants pale green, sometimes purplish, forming tufts, not turf; shoots extra- and intravaginal, with fascicles of slender intravaginal shoots. Culms (15–)20–80 cm tall, several per tuft. Leaf sheaths longer than basal internodes, shorter than upper internodes, several times as long as blades; blades flat or folded with margins inrolled, thin to moderately thin, 3–9 cm × 1–2 mm, of tillers intravaginal ones setiform, folded with inrolled margins, papery to thickly papery, to 45 cm × 0.5–1 mm, surfaces smooth, often adaxially pubescent; ligule 0.5–2 mm, apex truncate, abaxially scabrid. Panicle open, oblong to narrowly pyramidal, 5–10(–15) × 2–4(–5) cm; branches ascending or spreading, 3–5 per node, scabrid, longest 2–5 cm with 6–18 spikelets in distal 1/2–2/3. Spikelets ovate, frequently purple tinged, 4–5 mm, florets 2–5; glumes subequal, apex acuminate, keel scabrid, lower glume 2.2–3 mm, 1-veined, upper glume 2.5–3.2 mm, 3-veined; lemmas 2.5–3.5(–4) mm, apex acute, narrowly membranous, keel villous for 2/3 of length, marginal veins for 1/2 length, intermediate veins glabrous; palea smooth to minutely bumpy between keels, keels scabrid. Anthers 1.3–2 mm. Fl. and fr. Jun–Jul, fr. Jul–Sep. 2n = 28, 46, 51, 56, 63, 66, 72.
Coniferous and Quercus forest margins, grasslands on slopes; 500–4400 m. Gansu, Guizhou, Hebei, Heilongjiang, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan [Afghanistan, Bhutan, India, Kazakhstan, Kyrgyzstan, Mongolia, Nepal, Pakistan, Russia, Tajikistan, Uzbekistan; SW Asia, Europe; introduced in North America].
This subspecies is probably introduced, at least in part, in China. It grades into subsp. pratensis.