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''Echinochloa crus-galli'' is a type of wild grass originating from tropical Asia that was formerly classified as a type of panicum grass. It is commonly known as cockspur (or cockspur grass), barnyard millet, Japanese millet, water grass, common barnyard grass, or simply "barnyard grass" (which may refer to any species of ''Echinochloa'' or the genus as a whole however). This plant can grow to 60" (1.5 m) in height and has long, flat leaves which are often purplish at the base. Most stems are upright, but some will spread out over the ground. Stems are flattened at the base. The seed heads are a distinctive feature, often purplish, with large millet-like seeds in crowded spikelets. Considered one of the world's worst weeds, it reduces crop yields and causes forage crops to fail by removing up to 80% of the available soil nitrogen. The high levels of nitrates it accumulates can poison livestock. It acts as a host for several mosaic virus diseases. Heavy infestations can interfere with mechanical harvesting. Individual plants can produce up to 40,000 seeds per year. Water, birds, insects, machinery, and animal feet disperse it, but contaminated seed is probably the most common dispersal method. == Description== Polymorphous coarse, tufted annual, tall and often weedy; culms erect to decumbent, 0.8-1.5 m tall, rather thick, branching at base. Leaves flat, glabrous, elongate, 30–50 cm long, 1–2 cm broad, scabrous, slightly thickened at margin; ligules absent; sheaths smooth, lower ones often reddish; panicle 8–30 cm long, green or purple, exerted, somewhat nodding, densely branched, the branches to 5 cm long, erect or ascending sessile; Spikelets 3–4 mm long, densely arranged on branches, ovoid, awnless, but move often long-awned, pale green to dull purple, short-bristly along veins; racemes spreading, ascending or appressed, the lower somewhat distant, as much as 10 cm long, sometimes branched; glumes and lower lemma minutely hairy on surface with longer more rigid hairs on veins; first glume about two-fifths as long as spikelet, deltoid, the second as long as the spikelet, short-awned; sterile lemma membranous, with a straight scabrous awn, 2–4 cm long or awnless; fertile lemma ovate-elliptic, acute, pale yellow, lustrous, smooth, 3-3.5 mm long. Fl. Aug.-Oct.; seed maturing Sept.-Oct., up to 40,000/plant. Var. crusgalli has long, somewhat spreading papillose cilia at the summits of the internodes and bases of the branches in the inflorescence and short, very thick papillose cilia along the lateral nerves of the 2nd glume, sterile lemma, and somewhat spreading spikes", and sterile lemmas with awns 0–10 mm long.〔http://www.hort.purdue.edu/newcrop/duke_energy/Echinochloa_crusgalli.html〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Echinochloa crus-galli」の詳細全文を読む スポンサード リンク
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