I ran across this plant while in central NH, in early-mid July, on the side of the road in the middle of a campground (of all places!). It was growing near, but not in a stream, in dappled/part shade. I am sure it self-seeded there, so it must be hardy to at least zone 5. It reminded me of both an anemone, and a Japanese wood poppy, but the foliage isn't really right for either of those.
Any ideas?
