Virginia dayflower. When I saw this flower, I thought I would probably look it up and find out it was an Asiatic dayflower, this plant's non-native, invasive relative which is apparently pretty common around New York. But it turns out that I am pretty sure this is our native Virginia dayflower: as you can see in the picture, the lower petal is blue. Asiatic dayflowers have a white lower petal. Both have two pretty light-to-indigo blue upper petals that look a little like Mickey Mouse ears when the flower is unfolded.
Growing alongside a stairway down the west-side path below 116th street in Morningside Park, Manhattan.
