Asplenium ruta-muraria L.

Asplenium ruta-muraria L.. Asplenium ruta-muraria is a species of fern commonly known as wall-rue. It is a very small epipetric species, growing exclusively on limestone and other calcareous rocks. Its fronds are bluish-green and are heavily sub-divided, becoming up to 12 cm (4.7 in) in length.