Distribution: East of the Cascades in Washington; British Columbia south to California, east to Minnesota and Wisconsin.
Habitat: Marshy areas, often in standing water.
Conservation Status: Not of concern
Aquatic, scapose perennials, the scapes 0.5-3 dm. tall, often exceeded by the leaves.
Leaves all basal, long-petiolate, the blades from narrowly linear to linear-lanceolate or narrowly elliptic, up to 2 cm. broad, often floating when linear.
Flowers in compound, bracteate, terminal panicles, the panicles branches in 2-4 whorles along the axis, the branches with one whorl of pedicles, the upper whorl reduced, the flowers on pedicles from the axis; sepals 3, 2.5 mm. long, greenish, purple-margined, persistent; petals 3, slightly larger than the sepals, reddish- or purplish-tinged; stamens 6, opposite the petals; pistils 10-20 in a single whorl, the sub-terminal style short, persistent.
Achenes sub-orbicular, 2 mm. broad, the style somewhat curled.