Dicentra cucullaria (Dutchman's Britches)
These aren't mine. They were in the park. I have managed to grow these from seed in my garden. They are not yet ready to bloom, as they are on my north wall, but I will get a few pics when they do. Mine are more yellow, than white.
If you don't know, just the collecting of seed from these treasures is a horticulturists challenge. Getting them to germinate is beyond hope, almost.