Japan Flora: Annual; culms many, tufted, filiform, 5-40 cm. long; leaves aggregated at the base of the culm, glabrous, much shorter than the culm, the sheaths glabrous, with few long white hairs on the mouth; inflo­rescence with few to rather many spikelets, and 1-5 slender smooth rays 2-5 cm. long, the bracts setaceous or scaly, short; spikele任 oblong, 3-5 mm. long, angled, chestnut-brown, the lateral peduncled, the terminal sessile; scales ovate, about 2 mm. long, subacute, keeled; achenes pale, obovate-orbicular, 0.8 mm. long, 3-angled, inconspicuously undulate-corrugate and puncticulate; style-base bulbose.  Aug.-Oct. Waste grounds and cultivated fields; Hokkaido, Honshu, Shikoku, Kyushu. Korea, Formosa, China, and India.

var. capitata (Miq.) Ohwi. Spike­ lets or nearly all of them sessile, in a head. Aug.-Oct. Honshu (centr. distr. and westw.), Shikoku, Kyushu. Ryukyus.