Description from Flora of China
Alopecurus monspeliensis Linnaeus, Sp. Pl. 1: 61. 1753.
Annual, tufted. Culms erect or geniculate, up to 60 cm tall. Leaf blades narrowly to broadly linear, 2–13 cm, 2–9 mm wide, adaxial surface and margins scabrid, abaxial surface smooth, apex acute; ligule 2–8 mm. Panicle narrowly oblong in outline, dense, spikelike, sometimes slightly lobed, 1–10 cm, pale green, thickly clothed in yellow bristles. Spikelets narrowly oblong, 1.5–2.5 mm; glumes narrowly obovate-oblong, puberulous, vein scabrid-aculeate, margins ciliate, apex emarginate, apex of lobes slightly acute, awned from sinus; awn 2.5–4 times as long as glume body; lemma obovate, 1–1.2 mm, apex slightly 4-toothed, midvein extended into a fine, straight, readily deciduous, 1.5–2 mm awn; palea as long as lemma. Stamens 3, anthers ca. 0.8 mm. Caryopsis obovate-oblong, ca. 1 mm. Fl. and fr. May–Oct.
This is a widely introduced weed naturalized in most warm-temperate regions.
Moist places, streamsides; below 3000 m. Anhui, Fujian, Gansu, Guangdong, Hebei, Henan, Jiangsu, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang [India, Kazakhstan, Kyrgyzstan, Mongolia, Pakistan, Russia, Tajikistan, Turkmenistan, Uzbekistan; N and S Africa, SW Asia (Caucasus), Europe].