Japan Flora: Rhizomes long-creep­ing; stems stout, solid, 1-2 m. long; leaves glaucous, flat, smooth, 0.5-1.3 m. long, 1-2 cm. wide, narrowed into an obtuse apex, thickish and rather soft, the sheaths without ligules, their margins overlapping, not closed, rounded and scarious on both sides at mouth; spike terminal, erect, the bracts leafy and caducous; staminate portion of the spike shorter than the pistillate portion, the anthers linear, 2-3 mm. long, with a globose appendage at apex, the pistillate portion contiguous on the staminate, 10-20 cm. long; fruit lanceolate on a long bristly stipe; style elongate. July-Aug. Ponds and riversides in lowlands.

Hokkaido, Honshu, Shikoku, Ky­ushu.  Widely distributed in the temperate regions of the N. Hemisphere.