Distribution: Occurring on both sides of the Cascades in Washington; Vancouver Island, British Columbia south to central California; primary distribution in central and eastern North America.
Habitat: Ditches, ponds, lakes, swampy areas.
Conservation Status: Not of concern
Aquatic, scapose, tuber-bearing perennials from strong rhizomes, the scapes up to 5 dm. long.
Leaves mostly emersed, but often submerged and the blades floating; blades sagittate or hastate, up to 2.5 dm. long and nearly as broad; submerged leaves sometimes bladeless and greatly elongate, 4-10 mm. broad.
Flowers in 2-8 whorles of 3 in bracteate racemes, the bracts 5-10 mm. long, blunt, hooded; pedicles 1-5 cm. long, ascending, in both the pistillate flowers (lower whorles) and staminate flowers.(upper whorles), or the plants sometimes monoecious; sepals 3, 5-10 mm. long, persistent; petals 3, white, twice as long as the sepals; stamens more than 20; pistils many on a globose receptacle.
Achenes 2.5-4 mm. long, winged, with a stylar beak strongly up-turned, 0.5-1.5 mm. long.