Unknown

This is the flower I mentioned a few days ago. It is all over our wooded area and I always thought it was a kind of wood anemone , but Snow Goose Blues says the leaf is wrong for an anemone. I looked it up with confidence and found he was right! It is not in either of my wild flower books, nor can I find it on Google. I know you all like a challenge!
Thank you all for your lovely comments about my garden,