RANGE EXTENSION SOUTHWARD IN COMMON MILKWEED, ASCLEPIAS-SYRIACA L

Common milkweed is rapidly expanding its range southward. It occurs abundantly in the southern Piedmont of North Carolina and has recently been collected from Cherokee County in the northern Piedmont of South Carolina. Asclepias syriaca has also been collected from four counties in the Piedmont, Ridge and Valley, and Cumberland Plateau regions of northern Georgia. Reasons for the rapid spread of this native plant are unclear, but it does possess strong colonizing potential due to its numerous comose seeds, gemmiferous roots, and limited self-compatibility. It is possible that wind dispersal of seeds is enhanced by drafting off of large, high-speed trucks along interstate highways.