Ambrosia chamissonis
silver beachweed, beach bur, cutleaf beach bur, silver burr-ragweed
WTU specimens
Other herbaria

Distribution: Maritime shoreline from British Columbia to california

Habitat: Common on sandy beaches above high tide level

Flowers: June-September

Origin: Native

Conservation Status: Not of concern

Description:
General:

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:

Leaves mostly alternate, petiolate, the toothed to pinnately dissected blade 2-7 cm. long and 8-40 mm. wide.

Flowers:

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.

Fruits:

Achene

Accepted Name:
Ambrosia chamissonis (Less.) Greene
Publication: Man. Bot. San Francisco. 188. 1894. 1894.

Synonyms & Misapplications:
Ambrosia chamissonis (Less.) Greene var. bipinnatisecta (Less.) J.T. Howell [HC]
Ambrosia chamissonis (Less.) Greene var. chamissonis [HC]
Franseria chamissonis Less. ssp. bipinnatisecta (Less.) Wiggins & Stockw.
Franseria chamissonis Less. ssp. chamissonis
Franseria chamissonis Less. var. bipinnatisecta Less.
Franseria chamissonis Less. var. chamissonis
Additional Resources:

PNW Herbaria: Specimen records of Ambrosia chamissonis in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Ambrosia chamissonis checklist entry.

E-Flora BC: Ambrosia chamissonis atlas page.

CalPhotos: Ambrosia chamissonis photos.

USDA Plants: Ambrosia chamissonis information.

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