Bidens amplectens, a member of the sunflower family (Asteraceae), is an herb with branched stems, from 1.5 to 3 m (5 to 10 ft) tall. Sparsely pubescent leaves are pinnately compound, 9 to 15 cm (14 to 22 in) long with 3 to 5 leaflets. Diffuse compound cymes with lateral branches have 10 to 30 flower heads. Ray florets are yellow, 7 to 9 per head, and disk florets are 40 to 60 per head with yellow corollas. Achenes are gray, straight, and wingless, 5 to 8 mm (0.2 to 0.3 in) long. Achenes (dry fruit) are gray, straight, wingless, 5 to 8 mm (0.2 to 0.3 in) long and 1 mm (0.04 in) wide, sparsely setose (bristly) on margins and faces.