I would greatly appreciate any leads on the identity of this vine
I saw in flower today, in the Shenandoah National Park, Virginia.

1. http://www.nyx.net/~dhcox/park/sideview.jpg
1. http://www.nyx.net/~dhcox/park/diagview.jpg
1. http://www.nyx.net/~dhcox/park/headon.jpg
1. http://www.nyx.net/~dhcox/park/buds.jpg
1. http://www.nyx.net/~dhcox/park/leaf.jpg

The flower was a little under an inch long. Most of the flower buds
had yet to open. The leafs were very variable in size; the one I
show was about 2.5 inches across (smaller ones are visible in the
buds.jpg). Hopefully the pictures show the white "fuzz" or hair
inside the flower (whatever flower part it is, it looks fuzzy),
and the black anthers (I am assuming they are anthers).

I have spent a fair amount of time in the references and this one really
has me stumped.