Japan Flora: Rhizomes densely tufted; culms erect, 30-60 cm. long, rather firm; leaf-blades flat, deep green, 5-10 mm. wide, the basal sheaths bladeless, dark reddish; spikes 3-6, contiguous except the lower ones, the terminal one staminate, pale, filiform, 2-3 cm. long, shorter than the pistillate, the pistillate cylindric, rather loosely to rather densely many­flowered, erect, 2-5 cm. long, the bracts leaflike, longer than the culm, long-sheathing; pistillate scales small, broadly ovate, obtuse, entire, pale; perigynia 3-4 times longer than the scales, narrowly ovoid, 3.5-5 mm. long, inflated, erect-patent, obso- letely 3-angled, glabrous, olive-colored, prominendy nerved, gradually rather long-beaked, obliquely truncate and hyaline at tip; stigmas 3, slender, short. Apr.-June. Wet places in lowlands and hills, especially along streams.

Hokkaido, Hon­shu, Shikoku, Kyushu; common.  Ryukyus, Korea, and China.