Anemone is a genus of quite ordinary flowers, but some of them are rare, as is Anemone sylvestris - with its fairly big white flowers you are bound to see them if they're there at all.
Which they aren't on most places. These here I've found close to one of the hot lands of Lower Lobau which I visit on a regular basis. (You know the one, close to Mühlleitner Furt ... no, not that one! Anyway, a secret place I can't post on the world wide web.)