Physaria alpina is a great specialty of the Mosquito and Saguage mountains in central Colorado. It was only named in the 1980's: wonder what people thought it was before that? People includes me, since I hiked up there back then and must have seen it!
Ranunculus eschscholtzii may be the most annoying of all buttercups to spell. In Colorado, it is much less common than R. adoneus, and just as lovely.
Horseshoe has fine displays of Dryas octopetala, literally carpeting the slopes! And there is more (much much more)...but this should keep you amused for a while!