Description from Flora of China
Alopecurus agrestis Linnaeus.
Annual, tufted. Culms erect or geniculately ascending, up to 80 cm tall. Leaf sheaths smooth, glabrous, upper sheaths slightly inflated; leaf blades 3–16 cm, 2–9 mm wide, glabrous, abaxial surface smooth or scabrid, adaxial surface scabrid; ligule 2–5 mm. Panicle narrowly cylindrical, up to 10 cm, tapering toward apex, yellow-green, pale green, or purplish. Spikelets narrowly oblong, 4.5–7.5 mm; glumes leathery, punctate-scabrid, keels narrowly winged, wings shortly pilose below, scabrid above, lateral veins very shortly pilose near base, margins connate in lower 1/3–1/2, apices acute; lemma slightly longer than glumes, margins connate in lower 1/3–1/2, awned from near base, apex acute; awn exserted 4–8 mm from spikelet, geniculate. Anthers pale yellow, 2.5–4 mm. 2n = 14.
This species is adventive or introduced as a fodder grass in North America, Australia, and other temperate regions.
Fields, introduced. Taiwan (Taipei) [Kazakhstan, Kyrgyzstan, Pakistan, Russia, Tajikistan, Turkmenistan, Uzbekistan; SW Asia, Europe].