Bidens cernua is a species of flowering plant in the aster family, Asteraceae. It is commonly called nodding beggarticks or nodding bur-marigold. Bidens cernua is distributed throughout much of Eurasia and North America.Flora of North America, Bidens cernua Linnaeus, Sp. Pl. 2: 832. 1753. Flora of China, 柳叶鬼针草 liu ye gui zhen cao, Bidens cernua Linnaeus, Sp. Pl. 2: 832. 1753Biota of North America Program 2014 county distribution mapAltervista Flora Italiana, Forbicina intera, Bidens cernua L. includes photos and European distribution map
Description Bidens cernua is an annual species growing roughly 1m tall, with a fibrous root. Stems are rigid and often either simple or beached. Stem leaves are simple, unstalked, and opposite with saw-toothed to almost smooth margins.
It has yellow flowers with 6–8 ray narrowly lance shaped petals around a central disk. The hemispheric heads are solitary at the ends of branches and nod with age.
The achenes are narrowly wedge-shaped and 4-sided, flattened and ribbed. The pappus has 3–4 barbed bristles.
Distribution and abundance Bidens cernua is distributed throughout much of Eurasia and North America.
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