Japan Flora: Rhi­zomes elongate; culms 7分-150 cm. long, stout, 3-angled, leafy below, globosely thickened at base; leaves flat, 5-10 mm. wide, gradually narrowed upward; inflorescence terminal, usually simple, with 3-8 rays to 7 cm. long, the bracts 2-4, leaflike, elongate; spikelets oblong, 2 or 3 on each ray, 10-20 mm. long, 6-8 mm. across; scales oblong, hyaline, brownish, nerve­less, 5-6 mm. long, pubcrulent, emarginate, the midrib end­ing in a recurved awn 2-3 mm. long; achenes obovate, 3.5-4 mm. long, cuneate at base, 3-angled, at first whitish, finally dark brown, lustrous, with equal flat sides, the bristles 6, shorter than the scale, retrorsely scabrous. July-Oct Marshy places and shallow waters.

Hokkaido, Honshu, Shi­koku, Kyushu. e. Asia, Australia, and N. America.