Japan Flora: Rhizomes short, tufted; culms 20-60 cm. long, scabrous on the angles; leaf-blades 2-3 mm. wide, rather firm, deep green, sometimes slightly curved upward, gradually long-attenuate; inflorescence a terminal spike 3-5 cm. long, dense, ovate-oblong, the bracts all scalelike, or the lower 1-3 nearly foliaceous; spikes numerous, andro­gynous; globular-ovoid, 5-8 mm. long; pistillate scales ovate, acute, midrib green; perigynia longer than the scales, 4-4.5 mm. long, ovate-lanceolate, nerved, planoconvex, the margins acute, slightly winged above the middle, scabrous toward tip, gradually long-beaked, the beak flat, 2-toothed; achenes small; stigmas rather long, slender.  May-July. Wet places in mountains.

sw. Hokkaido, Honshu (ne. part s. to centr. distr.); rather common.