Burke: Bidens laevis vs. Bidens cernua

	Bidens laevis	Bidens cernua
		nodding beggar-ticks, bur-marigold
Habit		Annual, nearly glabrous throughout, 1-10 dm. tall.
Leaves		Leaves sessile, simple, lance-linear to lance-ovate, serrate to sub-entire, 4-20 cm. long and 5-45 mm. wide.
Flowers		Heads hemispheric, the disk 12-25 mm. wide, nodding in age; outer involucral bracts 5-8, lance-linear, leafy and spreading, inner bracts yellowish above; rays 6-8, yellow, up to 1.5 cm. long, or rarely wanting
Fruits		Achenes narrowly triangular, compressed-quadrangular, 5-8 mm. long, with persistent pappus of four retrorsly-barbed awns.

	Bidens laevis	Bidens cernua
Identification notes		The undivided leaves and large flowering heads with prominent ray flowers readily separates Bidens cernua from the other species of Bidens.
Flowering time		July-September
Habitat		Stream banks, pond and lake edges, and other wet places at low elevations.
Distribution	[WildflowerSearch map] [BONAP county map]	Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]
Origin		Native
Conservation status		Not of concern
Sibling taxa	B. amplissima, B. beckii, B. cernua, B. connata, B. frondosa, B. tripartita, B. vulgata	B. amplissima, B. beckii, B. connata, B. frondosa, B. tripartita, B. vulgata
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	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

Bidens laevis

Bidens cernua

nodding beggar-ticks, bur-marigold

Habit

Annual, nearly glabrous throughout, 1-10 dm. tall.

Leaves

Leaves sessile, simple, lance-linear to lance-ovate, serrate to sub-entire, 4-20 cm. long and 5-45 mm. wide.

Flowers

Heads hemispheric, the disk 12-25 mm. wide, nodding in age; outer involucral bracts 5-8, lance-linear, leafy and spreading, inner bracts yellowish above;

rays 6-8, yellow, up to 1.5 cm. long, or rarely wanting

Fruits

Achenes narrowly triangular, compressed-quadrangular, 5-8 mm. long, with persistent pappus of four retrorsly-barbed awns.