Japan Flora: Rhi­zomes elongate; stems terete, 20-30 cm. long, 2- or 3-leaved; leaves all cauline, slightly compressed, unitubulose, shorter than the stem, 1-2 mm. wide, perfectly septate; inflorescence rather large, terminal, with many loosely disposed small 2- or 3- flowered heads; flowers 4-5 mm. long including the capsule, the perianth-segments narrowly lanceolate, cuspidate, greenish, the inner longer than the outer; stamens 3, 2/3 as long as the outer perianth-segments, the anthers much shorter than the filaments; capsules lanceolate, mucronate, much longer than the perianth, brown，thin; seeds obovoid, about 0.6 mm. long. Aug.-Sept. Swampy places.

Hokkaido, Honshu, Shi­koku, Kyushu.  China, Korea, Manchuria to e. Siberia.