Japan Flora: Rhizomes slender, elongate, forming a tuber at apex in autumn; culms loose, solitary, terete, 7-30 cm. long, soft, naked, the basal sheaths 1 or 2，hyaline, bladeless, obliquely truncate at apex; spikelet solitary, pseudolateral, 7-10 mm. long, 3 mm. across, broadly lanceolate, acute, sessile, tawny to reddish brown, more or less lustrous; bract 1, terete, 1-4 cm, long, erect, continuous with the culm; scales obtuse, hyaline, 1-   5 mm. long, faintly nerved, oblong; stigmas 2; achenes broadly obovate, 2 mm. long, dark brown, lustrous, com­pressed, glabrous; bristles 4-5, twice as long as the achene, retrorsely scabrous; anthers 2.5 mm. long. July-Oct. Marshy places.

Hokkaido, Honshu, Shikoku, Kyushu. Formosa.