Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California; introduced in Illinois.

Habitat: Ponds and slow-moving streams.

Flowers: May-October

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind

Perennial, aquatic herbs, the stems freely branched, 1-6 dm. long.

Leaves 4-5 per whorl, the submersed ones 1.5-3 cm. long, pinnately dissected into 13-23 filiform segments, and gradually transitional to the linear-oblong, 10-15 mm. long, serrate bracts.

Inflorescence terminal, immersed to emersed, the flowers single in the axils of the bracts; sepals 4, attached to the top of the inferior ovary; petals 4, pale yellow, 1 mm. long; staminate flowers uppermost on the stem, stamens 4; stigmas very short, smooth.

Achene 1.5-2 mm. long.