Which poisonous weed is Xanthium strumarium, known for spiny burs?

Which poisonous weed is Xanthium strumarium, known for spiny burs? The answer is cocklebur.

Xanthium strumarium is commonly called cocklebur, including rough cocklebur, common cocklebur, and large cocklebur. It is an annual flowering plant in the daisy family, Asteraceae, and is recognized by its oval, spiny fruiting burs.

The burs are not simply decorative seed cases. Their hooked projections cling to animal fur, clothing, and other surfaces, allowing the plant to disperse its seeds. They can also float and travel along waterways. Each mature bur encloses two achenes, although typically only one seed germinates.

Cocklebur is poisonous chiefly because of compounds concentrated in the seeds and young seedlings, with poisoning especially important in livestock. Signs can include weakness, nausea, vomiting, and liver injury. The plant has also been used in traditional medicine, but medicinal use does not make every part safe. Teasel, ragweed, and burdock may have burs or burr-like structures, yet Xanthium strumarium is specifically cocklebur.