Distribution: Occurring chiefly west of the Cascades crest in Washington; Introduced from British Columbia to Oregon, and in Montana; native in central and eastern North America.
Habitat: Ponds, lakes and quiet streams
Origin: Introduced from eastern North America
Conservation Status: Not of concern
Submersed, dioecious, scapose perennials from rhizomes.
Leaves tufted, long, linear and submersed, thin, flat, 1-5 dm. long and 3-10 mm. broad.
Staminate flowers tiny, several hundred clustered in a sub-globose structure of 3 fused bracts, becoming deciduous and free-floating; pistillate flowers at the water surfaced, solitary on long, slender scapes, enclosed at the base in fused, tubular bracts on a peduncle 1-2 m. long, tending to coil; sepals 3, 2-3 cm. long; corolla white, 3-parted, 5 mm. wide; stigmas 3, 2-lobed.
Fruit 5-10 cm. long.