Distribution: Occurring west of the Cascades crest in Washington; southwestern British Columbia to southwestern Washington.

Habitat: Freshwater intertidal marshes, floating logs, and damp gravel.

Flowers: July-September

Origin: Introduced from Europe

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Bumblebees, bees, flies, wasps

Perennial, the stems 4-winged, erect, 4-10 dm. tall.

Leaves opposite, sessile, somewhat clasping, ovate-lanceolate to oblong-ovate, with translucent dots.

Inflorescence of leafy-bracteate cymes; sepals 5, pointed, not black-dotted; petals 5, pale yellow; flowers about 10 mm. wide; stamens numerous, styles 3.

Capsule 3-celled.