Japan Flora: Annual; culms 10-50 cm. long, glabrous; leaf-blades flat, smooth, glabrous; spike 4-7 cm. long, pale green; glumes of fertile florets linear- lanceolate, 3-nerved, 2.5-3 cm. long, 0.3-1 mm. wide, ciliate below the middle. May-July. Naturalized in waste places and cultivated fields.