Japan Flora: Tufted in small clumps, often forming a large colony; culms slender, 30-100 cm. long, few-leaved; radical leaves linear, 1-1.5 mm. wide; corymbs 4-5, interrupted, dense, with a few spikelets; spikelets lanceolate, 5-6 mm. long, dark reddish brown; achenes broadly obovate, 2 mm. long, faintly transversely wrinkled, the beak slightly shorter than the achene; bristles 6, slightly longer than the achene, smooth.    Wet places in lowlands; Hokkaido, Honshu, Shikoku, Kyushu; common.

The following are based on variations of the bristles: f. scabriseta (Makino) T. Koyama. Bristles an­trorsely scabrous. f. retrososcabra (Takeda) T. Ko­yama. Bristles re­trorsely scabrous. Korea.