3. Lolium perenne Linnaeus, Sp. Pl. 1: 83. 1753.
黑麦草 hei mai cao
Perennial, turf-forming. Culms tufted, erect or spreading, sometimes prostrate and rooting from lower nodes, 30–90 cm tall, 3–4-noded. Leaf blades soft, 5–20 cm × 3–6 mm, glabrous, young blades folded; auricles to 3 mm; ligule 2–2.5 mm. Raceme stiffly erect, or rarely slightly curved, 10–30 cm; rachis glabrous, smooth, spikelets usually less than their own length apart. Spikelets 0.8–2 cm, florets 5–10, rachilla internodes ca. 1 mm, smooth, glabrous; glume lanceolate, 1/3 as long to subequaling spikelet, 3–9-veined, margins narrowly membranous, apex acute or obtuse; lemmas oblong, herbaceous, 5–9 mm, 5-veined, smooth, apex obtuse to subacute, awnless; palea ciliolate along keels. Caryopsis length more than 3 times width. Fl. and fr. May–Jul. 2n = 14, 28.
Meadows, grassy places, moist roadsides. Commonly cultivated in China [Russia; N Africa, Europe].
This species is extensively cultivated in temperate regions of the world as an excellent forage and lawn grass. It is a variable species, with many cultivars (Perennial Rye Grass).