Japan Flora: Rhizome short; culms tufted, soft, 30-60 cm. long, scabrous on the prominent, acute angles; leaf-blades 3-7 mm. wide, flaccid, bright green; inflorescence rather dense, ovoid-cylindric, 3-6 cm. long, the bracts scalelike or the lower elongate, to 3 cm. long; spikes numerous, androgynous, ovoid-globular, 6-10 mm. long; scales pale, 1-nerved, acuminate; perigynia longer than the scales, spaading, broadly lanceolate，5 mm. long, thick, planoconvex, pale green, nerved, spongy and prominently thickened at the base, gradually long-beaked, the margins scabrous except at base. June-July. Moors; Hokkaido, Honshu (centr. distr. nordiw.). N. America.