4. Agrostis stolonifera Linnaeus, Sp. Pl. 1: 62. 1753.
西伯利亚剪股颖 xi bo li ya jian gu ying
Agrostis palustris Hudson; A. sibirica V. A. Petrov.
Perennial, tufted, stoloniferous; stolons slender, leafy, widely spreading, developing after anthesis. Culms erect or geniculate and rooting at base, 30–50(–100) cm tall. Leaf sheaths smooth; leaf blades linear, flat or inrolled, 4–10 cm × 2–5 mm, scaberulous, apex acute to acuminate; ligule on non-flowering shoots 2–3.5 mm, rounded to truncate, often lacerate. Panicle narrow, linear to lanceolate in outline, 5–20 cm, open only at anthesis, otherwise contracted, often dense; branches several per node, closely divided, ascending, scabrous, main branch at a node often bare in lower 1/3, but accompanied by shorter branches bearing spikelets to base. Spikelets 1.8–3 mm, yellowish green; glumes lanceolate, subequal or lower glume slightly longer, lower glume scabrous along keel distally, upper glume often smooth, apex acute; callus minutely hairy; lemma 3/4 as long to subequaling spikelet, usually awnless, apex rounded; palea 1/2–3/4 length of lemma. Anthers 0.8–1.5 mm. Fl. Aug.
Moist places along roadsides. Anhui, Gansu, Guizhou, Heilongjiang, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi, Xinjiang, Xizang, Yunnan [Bhutan, India, Japan, Mongolia, Nepal, Russia; C and SW Asia, Europe].
This is a widespread and polymorphic species, adventive in many temperate countries.