Bidens cernua
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.
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.