Japan Flora: Rhizomes creeping; culms 30-70 cm. long, loosely tufted in small clumps, 1-angled, somewhat scabrous; leaf-blades 3-4 mm. wide, flat, soft, somewhat glaucous beneath, the basal leaf-sheaths with blades, scarcely filamentous, stramineous, not keeled; spikes 5-S, contiguous or the upper ones sometimes overlapping, erect, the terminal staminate, 2-3 cm. long, the lateral pistil­late, cylindric, 3-5 cm. long, usually sessile; lowest bract leaf­like; pistillate scales narrowly oblong, dark reddish brown, acute; perigynia broader and shorter than the scales, elliptic, 2-2.5 mm. long, compressed-biconvex, often brown-spotted, nerveless, with a rather abrupt, long, sometimes scabrous beak minutely 2-toothed at the tip; stigmas 2, very long, slender, persistent, reddish brown. May-July. Abundant in wet places along mountain streams.

Hokkaido, Honshu (n. and centr. distr., and on Mount Daisen in Hoki Prov.). s. Sakhalin, and s. Kuriles.