Japan Flora: culms 30-50 cm. long, densely tufted, ribbed, about 1 mm. thick; spikelets scarcely proliferous, ovoid to narrowly so, densely many-flowered, 4-12 mm. long, 2.5-4 mm, thick; scales membranous, elliptic or oblong, about 2 mm. long, rounded at apex, pale and reddish ferrugineous; achenes obovate, 1.2 mm. long, tawny, lustrous, smooth, obtusely 3-angled, the style base depressed, 2/3 to nearly as wide as the body of the achene, rather acute on the basal angles, the bristles 6, smooth, about as long as the body of the achene. July-Oct Wet places; Honshu (Shinano Prov.; Kutsukake); rare. Korea.

var. attenuata. Brisdes retrorsely scabrous, usually slightly longer than the body of the achene. Wet places; Honshu, Shikoku, Kyushu. Ryukyus.