Distribution: Occurring west of the Cascades crest along the marine coastline beaches in Washington; British Columbia, south along the coast, to California.
Habitat: Common on sandy beaches above high tide level.
Flowers: June-September
Origin: Native
Growth Duration: Perennial
Conservation Status: Not of concern
Pollination: Wind
Monoecious, succulent perennial 2-10 dm. tall, forming large, lax clumps, the stems much branched below the surface, the herbage silvery with appressed hairs.
Leaves mostly alternate, petiolate, the toothed to pinnately dissected blade 2-7 cm. long and 8-40 mm. wide.
Staminate heads sub-sessile, forming congested, leafless, terminal spikes; pistillate heads borne below, in the axils of bracts; fruiting involucre a bur, 6-11 mm. long, with 2-4 series of flattened prickles.
Achene
PNW Herbaria: Specimen records of Ambrosia chamissonis in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Ambrosia chamissonis checklist entry
OregonFlora: Ambrosia chamissonis information
E-Flora BC: Ambrosia chamissonis atlas page
CalPhotos: Ambrosia chamissonis photos