Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia south to California; also in Illinois.
Habitat: Ponds and slow-moving streams.
Conservation Status: Not of concern
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.