Japan Flora: Rhizomes elongate; culms 40-100 cm. long, 3-angled, without nodes except at base, more or less thickened at base; leaves elongate, flat, 2-5 nun. wide; inflorescence capitate or with 1 or 2 short rays, the bracts 1-3, much longer than the inflorescence, leafiike; spikelets 1-6, sessile, ovoid, 8-15 mm. long, 6-8 mm. wide, lus­trous, reddish or yellowish brown; scales 3-6 nun. long, ellip­tic, hyaline, nerveless on both sides, pubescent, emarginate, the midrib prolonged into a slightly recurved awn 1-2 mm. long; achenes flattened, broadly obovate, 3 mm. long, tawny and lustrous, obtusely angled, the faces more or less concave, bristles none.  July-Oct Swampy places especially near seashores.

Hokkaido, Honshu, Shikoku, Kyushu. Sakhalin, Northeast China, Korea, and Ryukyus.