Japanese Panicgrass

Annuals; culm weak, slender, 30-120 cm high, branching and prostrate. Blade 5-30 cm long, 4-10 mm wide, thin; sheath glabrous, margins ciliate; ligule truncate, membranaceous, ca. 0.5 mm long, irregularly fringed with hairs. Panicle open, ovate or deltoid, 12-40 cm in length and width. Spikelets acute, ca. 2 mm long, elliptic, faintly dark green, sometimes purplish; lower glume triangular, acuminate or acute, 1/3 as long as spikelet; upper glume and lower lemma similar, acute, finely 5-veined, membranaceous, elliptic, 15-18 mm long, obtuse, smooth, shiny, greyish brown when mature.

Annual. Culms erect or ascending, sometimes rooting at lower nodes, 30–180 cm tall, nodes glabrous. Leaves cauline; leaf sheaths striate, glabrous, ciliate on the margins, especially toward the throat; leaf blades linear, 5–20 × 0.5–1.5 cm, subglabrous, base rounded, apex acuminate; ligule ca. 0.5 mm, a ciliolate membrane. Panicle ovate or orbicular in outline, 10–40 cm, loose, much branched; branches slender, flexuous, scabrid, with the spikelets in pairs and clustered toward the ends of the branches. Spikelets elliptic, 2–2.5 mm, sparsely puberulous; lower glume ovate, 1/2 length of spikelet, 1–3-veined, acute or acuminate; upper as long as spikelet, 5-veined; lower lemma similar to upper glume, palea absent; upper floret as long as spikelet, pale yellow, smooth, shiny. Fl. and fr. Sep–Nov. 2n = 36.

India, Malesia, Australia, China and Japan. Taiwan, in lowland forest margin.

Moist places. Anhui, Fujian, Guangdong, Guizhou, Hainan, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Shandong, Sichuan, Taiwan, Yunnan, Zhejiang [India, Japan, Korea, Philippines; Australia, Pacific Islands].

Panicum acroanthum Steudel; P. acroanthum var. brevi-pedicellatum Hackel.