Please identify this purple flower from Alaska

I have not been able to find this purple flower, (not the blue vetch behind it), in any of my 6 books of flowers found in Alaska. The picture was taken on the banks of the Colville River on the north side of the Brooks Range, Alaska. The picture was taken on June 27, 2007.

 

Some kind of daisy, still in the process of opening. I'd look under Aster and Erigeron.

 

Thank you Ron B. I have been busy with another project right now, but will look under those two flowers, (Aster and Erigeron), as soon as I get a bit more time.