This cosmopolitan weed of tropical to warm temperate regions has been widely recorded across North America, at least as an occasional adventive. But it is now common only in western regions, and rare in southeastern states (FNA 19, K, PL, W). Almost all Ky. records date from 1840 to 1940, with perhaps none after 1950 (M). Short (1840) noted: "A pestiferous species of cockle-bur, which, it is to be feared, will become extensively naturalized. As yet, I have only met with it on the commons of Portland, below the falls of the Ohio." In 1914, Gm noted: "frequent throughout the western half of the State, and it is noticeable among our species of cockleburs because of its large, yellow, three-forked spines, the latter often as much as three-fourth inch in length." Was the disappearance of this species perhaps associated with the decline of sheep or other changes in farming?