Distribution: Occurring chiefly west of the Cascades crest in Washington; Washington and California; also in eastern North America.
Habitat: Roadsides, fields, waste ground.
Flowers: June-September
Growth Duration: Biennial, Perennial
Conservation Status: Not of concern
Pollination: Bees, flies, beetles, wasps
Usually glabrous perennials, the 1-5 stems 10-50 cm. tall, usually procumbent and branched above.
Leaves basal and cauline, the blades 2-8 cm. long, oblong, 1-3 pinnately lobed, the ultimate lobes cylindric and fleshy.
Heads 10-50 in flat-topped inflorescences; involucre bracts oblong to narrowly triangular, unequal, dark greenish to brownish with pale to dark brown scarious margins, 0.2-1 mm. wide; ray flowers strap-shaped, white, 10-34, 10-16 mm. long; disk corollas yellow, 2.5 mm. long; pappus none.
Achenes pale to dark blackish-brown, with resin glands over twice as long as wide.
PNW Herbaria: Specimen records of Tripleurospermum maritimum in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Tripleurospermum maritimum checklist entry
OregonFlora: Tripleurospermum maritimum information
E-Flora BC: Tripleurospermum maritimum atlas page
CalPhotos: Tripleurospermum maritimum photos