A blurry macro shot, but I wanted it for my Plants of Alberta set : ) This is a native, small-flowered Clematis, in the Crowfoot or Buttercup family. It's a semi-woody vine, which climbs on trees and bushes for support. The white flowers are 12-20 mm across. This vine was growing in Jim Coutts' amazing homestead garden, just north east of Nanton, south of Calgary.