Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; British Columbia to California, east to Montana, Wyoming, Utah, and Arizona, also in northeastern North America.

Habitat: Ponds and slow-moving streams.

Flowers: June-August

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind

Perennial, aquatic herbs, the stems simple or branched, 2-10 dm. long.

Leaves 1-2.5 cm. long, in whorls of 4-5, dissected into 13-21 filiform segments, appearing comb-like, gradually transitional to the bracts; bracts ovate-oblong, 7-10 mm. long, the lower comb-like, transitional to serrulate in the upper bracts.

Inflorescence simple to forked, submerged to emergent; flowers single, subtended by whitish, rough-edged bracteoles 1-2 mm. long; sepals 4, attached to the top of the inferior ovary, whitish, serrate; petals 4, about 2.5 mm. long, quickly deciduous; stamens 8 on the staminate flowers; stigmas plumose on the pistillate flowers.

Achene smooth, 2 mm. long.