Japan Flora: Steins erect, 40-80 cm. long; leaves erect, longer than the stem, 4-8 mm. wide, keeled beneath; spikes erect, the lower bracts about as long as the spike, the pistillate heads 4-6, relatively wide apart, usually sessile, 2-2.5 cm. in diameter in fruit, the staminate 4-7, interrupted; fruit rhombic-ovoid or fusiform, 6-7 mm. long, about 2 mm. wide, the pedicels 2-3 nun. long.  Aug. Shallow ponds in low­lands.

Honshu (Kanto Distr. and westw.), Kyushu. Burma and India.