Asplenium ruta-muraria is a species of fern commonly known as wall-rue.<ref>Template:Cite book</ref> In Germany, it is known as Mauerraute or Mauerstreifenfarn. It is a very small epipetric species, growing exclusively on limestone and other calcareous rocks.
Distribution and habitat
Asplenium ruta-muraria is native to Europe, east Asia, and eastern North America.Template:Sfn In North America, its range extends from western New England southwest along the Appalachian Mountains to Alabama and Tennessee. It is also found in the Ozarks and in southern Indiana and Ohio, with outlying occurrences in Michigan, Ontario, Quebec, and Clinton County, Iowa.Template:Sfn
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.