roundleaf greenbrier

Smilax rotundifolia, known as roundleaf greenbrier and common greenbrier, is a woody vine native to the eastern and south-central United States and to eastern Canada. It is a common and conspicuous part of the natural forest ecosystems in much of its native range. The leaves are glossy green, petioled, alternate, and circular to heart-shaped. They are generally 5–13 cm long. Common greenbrier climbs other plants using green tendrils growing out of the petioles.