photos taken April 2014.
From Wikipedia:
Fritillaria meleagris is a species of flowering plant in the family Liliaceae. Its common names include snake’s head fritillary, snake’s head (the original English name), chess flower, frog-cup, guinea-hen flower, leper lily (because its shape resembled the bell once carried by lepers), Lazarus bell, checkered lily or, in northern Europe, simply fritillary.
The flower has a chequered pattern in shades of purple, or is sometimes pure white. It flowers from March to May and grows between 15–40 cm (6–16 in) in height. The plant has a button-shaped bulb, about 2 cm in diameter, containing poisonous alkaloids. It grows in grasslands in damp soils and river meadows at altitudes up to 800 m (2,625 ft).
Let the Images Speak 
We have these in our garden. A lovely flower and well photographed too!
You are lucky, this lovely fower doesn’t grow anywhere.
Wie schön ❤
Danke 🙂