Here is a clump of C. parviflorum growing in our botanical garden (my workplace). I rescued them from western Newfoundland when a new road was being constructed.
That is one of the nicest clumps I've ever seen, and what a setting! It seems to have the less-twisted petals characteristic of specimens from Newfoundland, as well! Cool!
I've seen some here with no twisting at all, but those grow in the northernmost areas. I'm waiting for a road to go through some cyps in that area in order to save them and add them to our collection!