Just wanted to add that the Snake's Head Fritillary is the official flower of the province of Uppland... it flowers every spring on a meadow just outside the town, I believe the largest occurence of them in Scandinavia. Lots of people come there to see the flowers, and there is a legend that there once was a battle there between Swedes and Danes long ago. For every dead Dane a purple flower would grow, and for every Swede a white. The Swedes won, which explains the fact that there are many more purple flowers than white...
(Incidentally, this area is a really great area for birds as well... just today I saw a Red-necked Phalarope there.)