Japan Flora: Rhizomes short; culms 30-50 cm. long, firm, acutely 4-angled, 1-2 mm. thick; sheaths often somewhat reddish; spikelets narrowly ovoid to broadly lanceolate, 8-17 mm. long, 3-5 mm. thick, often slightly bent, densely many-flowered, ferrugineous; scales ob­long, obtuse, dull, 3-4 mm. long; achenes obovate, 1.5-2 mm. long, compressed-trigonous, tawny, nearly smooth, the style base compressed, trigonous, spongy, rather large, the bristles 6, firm, erect, densely retrorsely spinulose, with spinulae 1 to 2 times as wide as the bristle. June-Oct. Honshu (Chugoku), Shikoku, Kyushu. Ryukyus, Formosa, China, India, Malaysia, and Australia.

Var. tsurumachii (Ohwi) Ohwi. Culms slighdy softer, the scales obtuse at apex. Honshu (Hitachi Prov.)