The image depicts a close-up view of a Fringe lichen (Heterodermia) growing on sandstone along the Lake Somerville Trailway near Nails Creek Unit of Somerville Lake State Park in Texas.
The lichen is light green and has a wavy, irregular border around its edges, giving it a "fringed" appearance. The coloration is uneven due to the varying shades of tan, brown, and gray that are present on the stone beneath. A small portion of another lichen can be seen in the upper left corner; however, it is not clear what type of lichen this is.
Overall, the image showcases the unique characteristics of Fringe lichen growing on sandstone in its natural habitat. – AI vision