Rough Cocklebur - Xanthium strumarium
MNPS Threat Rank
Stems erect, strigose, 10–100 cm, . Leaf blades cordate-deltate, 2–12 cm long, serrate, sometimes shallowly few-lobed, sparsely short-hispid. Burs 2–4 cm long, 2-beaked, stipitate-glandular (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Our plants are variety canadense
(Mill.) Torr.& A.Gray
Xanthium strumarium is distinguished from spiny clotbur (X. spinosum) by its broader cockleburs, more ovoid leaves on long petioles, and lack of spines.
Xanthium strumarium is distributed worldwide (53 degrees north to 33 degrees south latitude) but is most common in the temperate zone (Love and Dansereau 1959). It is a serious weed in Australia, India, South Africa, and the Americas.
There has been considerable controversy regarding the origin of cocklebur. Though first described from Europe, it is probably of American origin (Munz and Keck 1973). Love and Dansereau (1959) suggest that the cocklebur subspecies most abundant in North America (cavanilliesii) originated in Central America. The dates of its introduction to California are not known, but it may be pre-Columbian.
Observations in Montana Natural Heritage Program Database
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- Additional ReferencesLegend: View Online Publication
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- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.