Another interesting find along the Blue Ridge Parkway in western North Carolina (16 May 2021) was this vine in bloom.
Pipevine, Dutchman's-Pipe - Aristolochia macrophylla (syn. Isotrema macrophyllum)
References:

• Brandenburg, National Wildlife Federation Field Guide to Wildflowers of North America (Sterling, 2010), p. 78
• Foote and Jones, Native Shrubs and Woody Vines of the Southeast (Timber Press, 1989), p. 57, plate 9
• Radford et al., Manual of the Vascular Flora of the Carolinas (UNC Press, 1968), pp. 398-99
• Weakley, Flora of the Southeastern United States (UNC Herbarium, 2020), p. 158