Clematis viorna L.
I left the description of this species until last. Having seen so much variability in flower shape and color, I find it confusing. From the plants growing at Mt. Cuba Center in Delaware from wild collected seed from Alabama, to my own garden specimen, to those discussed with staff at the University of Tennessee herbarium, I would not be surprised to find more "types". From Dwayne Estes, I learned that certain traits of species west of the Appalachian Mountains differ from those east of the mountains.
Foliage is thin, some simple, some pinnately compound. The vine grows to about 13 feet (4 meters). Flower color can be pale lavender to reddish purple with yellow toward the tips. Flower shape can be urn -shaped to bell-shaped.
The range of viorna is almost solid from the southern parts of Pennsylvania west to Illinois, and south to Mississippi and including all eastern states to Georgia and Alabama, with areas of Arkansas and Missouri. In the wild Clematis viorna is found on stream banks and cliffs under tree canopy and flowers spring to summer.