Bidens cernua

Bidens cernua is a plant species in the sunflower family, widespread across much of Eurasia and North America. It is commonly called nodding beggarticks or nodding bur-marigold,

Bidens cernua sometimes grows as high as 400 cm (160 inches) tall in favorable conditions. The leaves are sessile with coarsely-toothed margins. The name "cernua" means "nodding," or "hanging ." This refers to the fact that the flower heads are sometimes oriented horizontally or downwards. The plant does best in wet habitats such as swamps, marshes, and flood plains.