Japan Flora: Perennial; leaves floating, slenderly petiolate, linear to oblong, 5-10 cm. long, obtuse at base or with obtuse auricles, 3-nerved; scapes elongate, usually to 60 cm. long; racemes simple, 1- or 2-nodcd; pistillate flowers 1-3, below the staminate, shortpedice lied, the staminate flowers 2-6, pedicellate; petals white; anthers yellow. Ponds.
Hokkaido; rare. Korea, Sakhalin, Siberia, and Europe.