I'm not certain if I have the identification correct, but these are 3 of the 4 types of this Spring ephemeral in bloom in my garden today.
First certainly looks like Anemone nemorosa, though I don't know if there's any very similar N American relatives. Second might be a double-flowered cultivar of the same. Third is a different species of Anemone, not sure which. Somewhat similar to A. blanda, but too few 'petals' per flower for that.
They all have the same structure. They grow out of a rhizome that looks (to me) like a petrified earthworm. The one in the 3rd photo is also in the background of the second photo. It's bluish flower is essentially the same as the flower in the 1st photo, except that it is blue. The 4th variety of these flowers I have (no photo here) is very similar to these 3 (same rhizome, same leaf size / structure) and the flower is blue (like the one in the 3rd photo) but the flower structure is completely different. It looks like a little blue daisy. I've often thought that flower #3 was a spontaneous hybrid of #1 and #4 (shape of #1 & colour of #4), but I have no idea if that's likely, let alone possible. I do know that #3 spontaneously appeared in my yard one day. (I could also note that #4 started to disappear from my yard around the same time... could #4 be mutating into #3? An unstable hybrid perhaps? These plants have always been botanical mysteries to me.)
#4 does sound like Anemone blanda or its close relative Anemone apennina. These often have a tendency to die out in garden cultivation, as they appear less well adapted to garden conditions than A. nemorosa. I've not heard of hybrids between A. blanda and A. nemorosa.
