Japan Flora: Rhizomes stout, extensively long-creeping; culms 20-60 cm. long, acutely angled, the angles scabrous in upper part; leaf-blades 3-5 mm. wide, rather firm, the basal sheaths (at least the lower ones) bladeless, brownish stramineous, sub- rigid, splitting somewhat into fibers; spikes 3 to 7, erect, the terminal staminate, the others pistillate, cylindric, contiguous to approximate, sessile, 2-6 cm. long, densely many-flowered, the bracts leaf-like; pistillate scales oblong, dark brown or dark purplish brown; perigynia slightly longer than the scales, 2.5-3 mm. long, nerveless, often with yellow resinous spots, smooth, abruptly contracted into a short minutely 2-toothed beak; stigmas 2. May-June. Wet places along streams in low mountains.

Hokkaido (sw. distr.), Honshu, Kyushu (n. distr.); rather common. Korea and n. China.