I tried to make a search for the le tters on the stamp, KӨK БАШ, Google translate first suggested KÖK HEAD, which didn't make much sense. Somewhere I recognised the letters in parenthesis in a text in Kirghiz, and when I used Google to translate this, it was translated as piles and the text was about hemorrhoids; I have a feeling that is not the name of the flower. I agree with Fermi that it looks more like Saussurea than Trollius.