– lowland cudweed, western marsh cudweed
Distribution: Widely distributed on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Great Plains.
Habitat: Open areas at low elevations where moist at least in spring.
– marsh cudweed
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to Oregon, east across the northern Rocky Mountains and northern Great Plains to eastern North America.
Habitat: Lake and pond margins, ephemeral pools, and other wet areas, sometimes where disturbed, at low to middle elevations.