Bidens frondosa L.
Family: Asteraceae
common beggar-ticks, devil's beggar-ticks
Bidens frondosa image
Hugh H. Iltis  
Etymology: Bidens: derived from Latin bis, "twice," and dens, "tooth," hence meaning "2-toothed" and referring to the bristles on the achenes
Plants: erect, annual, 8"-48" tall, mostly smooth forb
Leaves: stalked, 3-5 pinnately-divided into lance-like, toothed, pointed leaflets
Flowers: head with an orange to greenish-brown disk 1/3" wide, usually without rays, 5-9 leafy bracts usually longer than the disk; inflorescence a few long-stalked heads; blooms June-Oct.
Fruits: flat, brown to black, often hairy with 2-barbed awnsfruit drawing
Habitat: wet to moist; disturbed areas
Conservation Status: Native