Japan Flora: Stems more or less tufted, 20—40 cm. tall, compressed, narrowly 2-winged, about 2 mm. wide, few-leaved; leaves all cauline, 10-20 cm. long, 2-3 mm. wide, strongly compressed, pluritubulose, ensiform; inflorescence a compound cyme of usually numerous heads, large or rather small, the lowest bract leaflike，shorter than the inflorescence; flowers 4-5 mm. long including the capsule; perianth-segments narrowly lanceolate, cuspidate; stamens 3, 1/3-1/2 as long as the perianth-segments, the anthers shorter than the filaments; capsule 3-angled, lanceolate to elongate-ovoid，acute, brownish, slightly exceeding the perianth, rather membranous; seeds obovoid, about 0.6 mm. long.  Aug.-Nov. Wet places.

Hokkaido, Honshu, Shikoku, Kyushu; very common. Kamchatka, Korea, Formosa, China, and India; highly vari­able.