Bleeding Hearts (Dicentra spectabilis) and a Kwanzan Cherry (Prunus serrulata 'Kwanzan') in Madison Square Park:
Bleeding Hearts are just ridiculously gorgeous plants. And I see them with surprising regularity in the city this time of year. Madison Square Park has a great herbaceous plant collection, but I would also find this in planters outside of condos when I lived on the Upper East Side. The soft, chartreuse foliage is ephemeral -- which means all above-ground evidence of this plant will evaporate come July, only to surprise us again the following spring.
The origin for the common name, Bleeding Heart, is obvious:
It made me curious what the Latin name, Dicentra, meant. Di- obviously refers to two. At first I thought -centra may mean 100 or something like that (century, centimeter, etc.), but it turns out that Dicentra actually means two-hooded, referring to the upper part of the flower structure. Those pink heart halves aren't petals though, it turns out they are considered 'flowering stems.' A screen shot (from google books) showing a cross-section of the flower structure:
Finally, a shot of a Dicentra spectabilis 'Alba', or a white Bleeding Heart: