Anemone species
In Anemones, the ‘petals’ are in fact sepals.
Anemone nemorosa, Wood Anemone, is a common spring flower of damp woodland - often in extensive colonies. The leaves are finely lobed and the delicate, single flower (normally white, but can occasionally be pink or blue) is easily damaged.
Anemone apennina, Blue Anemone, escapes from gardens from time to time. Its leaves are similar to Anemone nemorosa, but there’s no mistaking the blue flowers.
Anemone x hybrida, Japanese Anemone (or Japanese Wind-flower), is another garden escape - tall, sparsely-branched with white to purple sepals densely hairy on the back.
Anemone coronaria, Poppy Anemone, is a true garden plant with many cultivars. It occasionally escapes into the wild.