Bidens cernua

Bidens cernua, commonly called nodding beggarticks or nodding bur-marigold, is a species of flowering plant in the aster family Asteraceae, first named by Carl Linnaeus, and found across much of Eurasia and North America. It is an annual herb growing to about 1 meter tall with rigid stems, opposite saw-toothed leaves and yellow flower heads with 6 to 8 ray petals that nod downward as they mature. Its narrow, wedge-shaped seeds carry 3 to 4 barbed bristles. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/