Dioscorea villosa /Yam Family
The flowers of this vine are small and barely noticible. The whorled, heart-shaped leaves are the most attractive feature. Look for the interesting, 3-winged fruits in the fall.
I call this vine the "Birth Control Pill Vine." It is related to the Mexican Yam, which was the source of the original steriods used in early birth control pills.
Where seen:Big South Fork NRRA, Great Smoky Mountains NP, Frozen Head SP, Oak Ridge Greenways, Norris Dam SP