Burke: Ambrosia chamissonis

	Ambrosia chamissonis
	silver beachweed, beach bur, cutleaf beach bur, silver bur-ragweed
Habit	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

	Ambrosia chamissonis
Flowering time	June-September
Habitat	Common on sandy beaches above high tide level.
Distribution	Occurring west of the Cascades crest along the marine coastline beaches in Washington; British Columbia, south along the coast, to California. [WildflowerSearch map] [BONAP county map]
Origin	Native
Conservation status	Not of concern
Sibling taxa	A. acanthicarpa, A. artemisiifolia, A. psilostachya, A. trifida
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Ambrosia chamissonis

silver beachweed, beach bur, cutleaf beach bur, silver bur-ragweed

Habit

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