This is a very common fern, mainly found growing in the mortar of stone or brick walls across Northern Ireland, including urban areas. Its original, natural, habitat is Carboniferous limestone, or more rarely, basalt rock, but it has been able to spread far beyond the ranges of occurrence of these rocks by colonising masonry. It is often accompanied by other typical wall plants such as Maidenhair Spleenwort, Hart's Tongue, Pellitory and Rusty-Back.
All names: Asplenium ruta-muraria L.