This is the flower of a Swamp Azalea, also known as Clammy Azalea (Rhododendron viscosum). Swamp Azalea is a wetland shrub in the eastern and southern United States. It is notable for its late blooming period. Unlike other azaleas, which bloom in May before they have fully leafed out, Swamp Azalea blooms in late June or July after its leaves are fully grown. The name "clammy" refers to the sticky hairs that line the outside of the tube formed by its petals. I took the photo above in the Great Swamp National Wildlife Refuge.