Although widely scattered in northern and eastern regions of North America, this alien is rare in southeastern states. In Ky. virtually the only records (M) are from Gm during 1888-1914: "common all along the [Nolin] river" in the counties mapped here, where it had "probably been introduced along the railroad and its seeds carried down stream." In 1914, he noted: "It has not spread to other parts of the State as was anticipated at the time, and is still restricted, as far as I have learned, to the region in which it was discovered."