Agrostis stolonifera Linnaeus var. gigantea (Roth) Koch; A. stolonifera subsp. gigantea (Roth) Maire & Weiler; A. sto-lonifera var. ramosa (S. F. Gray) Veldkamp; Vilfa alba (Linnaeus) P. Beauvois var. ramosa S. F. Gray.

Perennial, rhizomatous; rhizomes tough, scaly, spreading. Culms loosely tufted, ascending to prostrate at base, rooting and branching from lower nodes, up to 130 cm tall. Leaf sheaths smooth or scaberulous; leaf blades linear, flat, 5–30 cm × 3–10 mm, scabrid, apex acuminate; ligule on tillers 1.5–6 mm, as long as or longer than wide, toothed. Panicle oblong or conical in outline, 8–25 cm, contracted at first, open after anthesis; branches 5 or more per node, spreading, very scabrous, bearing branchlets nearly to base, spikelets clustered at the branch apices. Spikelets 2–3 mm, yellowish green or purplish; glumes elliptic-lanceolate, subequal or lower glume slightly longer, scabrid or pilosulous along upper keel and margins, apex acute; callus hairs 0.2–0.4 mm; lemma 2/3–3/4 spikelet length, glabrous, usually awnless, apex obtuse; palea 1/2–3/4 length of lemma. Anthers 1–1.5 mm. Fl. and fr. summer and autumn.

This is a widespread and polymorphic species, introduced for pasture or adventive in Australia, North America, and elsewhere. The name Agrostis alba Linnaeus has sometimes been used for this species, but the correct application of that name is uncertain.

Agrostis gigantea, A. capillaris, and A. stolonifera are closely related, widespread weeds, which sometimes hybridize. While the lemma is usually awnless, a small awnlet from at or near the apex may be present in some spikelets.

Moist ground, rough grasslands, as a field weed. Anhui, Gansu, Hebei, Heilongjiang, Henan, Hubei, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan, Zhejiang [Afghanistan, NW India, Japan, Korea, Mongolia, Nepal, Pakistan, Russia; N Africa, SW Asia, Europe].