Distribution: Occurring west of the Cascades crest in Washington; native to eastern North America.

Habitat: Lakeshores and marshes.

Flowers: June-August

Origin: Introduced from tidewaters in eastern North America

Growth Duration: Perennial

Conservation Status: Not of concern

Herbaceous stoloniferous perennials found on tidal mudflats, up to 40 cm, corms present.

Submersed, phyllodial, with lenticels, 5-40 cm long and 0.1-0.4 cm broad, rarely floating; petiole not angled, 2.4-4 cm; blade linear-lanceolate to ovate, 1-2.5 cm long and 0.3-1.5 cm broad, margins entire.

Inflorescences bracteate racemes with 2-7 whorls, floating, 2-11 cm long and 1.5-4.5 cm broad; peduncles 5-40 cm long; bracts connate greater than ¼ total length, slender and tapering to a point, 1.5-4.2 mm, delicate, not papillose; fruiting pedicels bending backward, cylindric to clavate, 0.2-1.1 cm; flowers imperfect, 0.4-1.2 cm in diameter; sepals 3, spreading to curving backward in staminate flowers, erect in pistillate flowers, enclosing the flower or fruiting head, persistent; petals 3, white, deciduous; filaments widened, longer than anthers, pubescence absent; anthers 2-chambered, splitting longitudinally; pistillate flowers pedicellate, sterile stamens occasionally present.

Fruiting heads 0.55-0.8 cm in diameter; achenes oblanceoloid with abaxial keel, 2 mm long and 1.5 mm broad, beaked; faces not tuberculate, wings 1 0r 2, crenate, glands 1 or absent; beak lateral and erect, 0.2-0.4 mm.