Tags: Fern.
Asplenium ruta-muraria is a species of fern commonly known as wall-rue. In Germany it is known as Mauerraute or Mauerstreifenfarn. It is a very small epipetric species growing exclusively on limestone and other calcareous rocks. It is native to both Europe and eastern North America. In Europe it commonly invades masonry and is a common species while in the United States it is more difficult to find favoring pockets in very well-weathered and rather dry limestone outcrops.
