Japan Flora: Rhizomes slender, elongate; culms 20-50 cm. long, slender, acutely angled, scab­rous; leaf-blades thin, 1-1.5 mm. wide; spikelets 3-5, androgyn­ous, distant, 2-3 mm. long, few-flowered, ebracteate or the lowest one with a setaceous bract; pistillate scales pale, ovate, acute; perigynia ovoid, slightly longer than the scales, 2.5-3 mm. long, pale yellowish, lustrous, biconvex, inflated, faintly nerved, subcoriaceous, abruptly attenuate and very short, smooth beaked, the mouth entire; achenes tightly inclosed; style bifid. June-July. Wet mossy places in woods.

Hok­kaido; rare. Subarctic regions of the N. Hemisphere.