Xanthium L. >

Burrs solitary or few together in the axils of alternate leaves, each burr containing 2 fruits Xanthium
consider the other alternative
Stems without spines
consider the other alternative
Leaves very shallowly and unevenly lobed, ovate, up to 12 cm long. Burrs ellipsoid, 15–30 mm long, with 2 larger terminal straight spines 6–8 mm long. Herb up to 1 m high. Weed of cultivation and waste places, particularly along creek flats. Fl. summer–autumn. South American Burr Xanthium cavanillesii