Spiny Cocklebur - Xanthium spinosum
Other Names:
Prickly Burweed, Bathhurst Burr
Stems erect, strigose, 30–120 cm with spines at the nodes. Leaf blades lanceolate, 2–8 cm long, deeply pinnately lobed, becoming more entire upward, strigose above canescent beneath. Burs 10–12 mm long, 1-beaked, puberulent, prickly (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).