Fritillaria meleagris

Snake's Head Fritillary

Yashica ML 50mm f2 lens

From Wikipedia:

"Fritillaria meleagris is a Eurasian species of flowering plant in the lily family Liliaceae. Its common names include snake's head fritillary, snake's head (the original English name), chess flower, frog-cup, guinea-hen flower, guinea flower, leper lily (because its shape resembled the bell once carried by lepers), Lazarus bell, chequered lily, chequered daffodil, drooping tulip or, in the British Isles, simply fritillary. The plant is native to the flood river plains of Europe where it grows in abundance. "