cocklebur
Xanthium strumarium                                         

Identifying Characteristics:

Seed:  long, oval bur with many hooked spines; 2 hooked teeth spreading from apex; brown to black in color

Seedling:  alternate leaves with long petioles; rough leaf surface with stiff hairs; toothed leaf margins; maroon to black lesions on stem

Mature Plant: erect, branched growth habit; male heads rounded in the axil of the leaves; female flowers below male florets

Method of Propagation: seed

Life Cycle: warm-season annual

References: Abaye, A. Ozzie. "Identification & Adaption: Common Grasses, Legumes & Non-leguminous Forbs of the Eastern United States."
Bryson, Charles T. & Michael S DeFelice. "Weeds of the Midwestern United States & Central Canada."