Bidens vulgata. ©Robert L. and Gerald Carr.Eastern Washington University.web.ewu.edu. (Accessed5/2014).

Bidens vulgata is an annual herb to 1.5 m tall, stems often reddish, smooth to hairy. 

Leaves alternate, stalked, pinnate, leaflets 3-5, narrow, tip long-pointed, base wedge-shaped, margins toothed (sometimes lobed). 

Flowers pale yellow, rays inconspicuous, disk flowers 40-60, heads hemispheric, 1-2.5 cm wide, outer bracts leaf-like 10-20, unequal, 1-4 cm long, loose, densely hairy, inner bracts 8-18, triangular, olive or brownish, about 1 cm long, flowers; Aug.-Oct. 

Bidens vulgata fruit. By Donald Cameron. Copyright © 2017 Donald Cameron. New England Wild Flower Society. gobotany.newenglandwild.org (Accessed 11/2017).

Fruit dry, 1-seeded achenes, 0.6-1 cm long, 0.4-0.6 cm wide, flat, widest near top, with two soft spines (horn-like) to 0.6 cm long. Seeds eaten by birds, plants eaten by rabbits (Martin et al. 1951). 

Wetland status: UPL. 

Frequency in NYC: Very infrequent. 

Origin: Native. 

Habitat: Open, disturbed areas, most fill. Very similar to B. frondosa, which has smaller heads with fewer bracts.