If you search along the weedy margins of the railroad track you cross just before you enter the refuge, any time between May and August, you'll probably find one of the most interesting flowering plants and plant-herbivore systems in the southeast, Passiflora incarnata, commonly called maypops or simply passion vine.
Passion vines produce beautiful, large flowers, that are easy to find once they open.
These large complex flowers open quickly at about 11 a.m., and last only one day before shriveling and setting fruit. Passion vine is chemically protected by cyanogenic glycosides, which prevent most plant-eating insects from feeding on it. It is, however, fed upon by the larvae of two specialized butterflies, which feed on no other plants. This is Agraulis vanillae, the gulf fritillary. These butterflies are often present in large numbers, especially from mid-late summer.