This is an interesting epiphytic, or tree-climbing, fern that will sometimes cover the trunks and limbs of a tree. I've seen Pecan trees in the Florida panhandle that are covered with this fern. When the fern's fronds dry they curl up, like the ones in this photo, giving it the nickname "resurrection fern". Note the brown sori, the dry spore-containing bodies on the underside of the fronds. The following photo shows fresh sori.
The spores are located on the back side of the pinnae ("leaves"). This Spleenwort has a black stipe ("stem").
Ferns can be very hard to tell apart, but this is a pretty easy one. Note the two bottom leaflets, they point downward. I photographed these in the Smokies.
