Anemonoides nemorosa, the wood anemone

Anemonoides nemorosa (syn. Anemone nemorosa), the wood anemone, a perennial herbaceous plant of the buttercup family Ranunculaceae. AKA windflower, thimbleweed, and smell fox. Common in the UK it spreads very slowly [as little as six feet per century] so often used as an indicator of ancient woodland.