Japan Flora: Rhizomes very short; steins terete or slightly compressed, not winged, 10-50 cm. long, 2- or 3-leaved; leaves all cauline, shorter than the stem, linear-subulate, unitubulose, perfectly septate; in­florescence terminal, cymose, the heads usually many, the lowest bract leaflike, short; flowers 4-5 mm. long including the capsule; perianth-segments lanceolate to narrowly lanceo­late, cuspidate; stamens 3, about half as long as the outer perianth-segments, the anthers much shorter than the fila­ments; capsules narrowly oblong, 3-angled, gradually acumi­nate at apex, exceeding the perianth, thin; seeds obovoid, 0.6 mm. long.- Aug.-Sept Swampy places.

Hokkaido, Hon­shu, Shikoku, Kyushu; common. Sakhalin, Ussuri, Ryukyus, Formosa, China to India.