A small evergreen fern. Mature leaves are about 2 inches wide at the base and up to about 16 inches long. Sori are distinctive: sharply round, brown and fairly flat. Similar in appearance to resurrection fern; the frond tips and sori are easy ways to tell them apart.
As the common name implies, the rock cap fern tends to grow on rocks. Found in moist, rocky woods.
The trail leading to Cascade Falls in Pembroke, Virginia, has more rock cap fern than I've seen anywhere else.