Distribution: Native and widespread in central and eastern United States; an occasional introduction in the Pacific Northwest.
Habitat: Waste places, usually in moist soil.
Conservation Status: Not of concern
Monoecious, coarse annual from a few decimeters to several meters tall with short, stiff hairs above.
Leaves opposite, petiolate, ovate or sub-orbicular, serrate, palmately 3- to 5-lobed, or without lobes in small plants, the blade 2 dm. long or more, rough on both sides.
Staminate heads small, numerous, short-pedunculate, in an elongate, bractless, spike-like inflorescence, the involucres 3-nerved; pistillate heads borne below, in the leaf axils, the involucres 5-10 mm. long in fruit, several-ribbed, each bearing a short spine at the summit.