Mainly seen on old walls, cliffs, scree and in crevices on rock which is rich in lime, Maidenhair Spleenwort is a very delicate little member of the Aspleniaceae family. An evergreen, It bears its leaves (4-20cm long) in dense rosette-like tufts. These leaves are pinnate, the petiole (or leaf-stalk) and rhachis (or midrib) are blackish. The pinnae (or leaflets) can be up to 40 on each side of the rhachis and more or less equal in size to each other. The sori (the vessels containing the spores, located on the rear of the leaves) are linear to oblong-linear. Remaining rhachis often continue to be present long after the leaf has perished. This is not a difficult fern to identify. It is widespread across the island of Ireland.
I first came across this little fern in Dalkey, Co Dublin in 1975 and I photographed it there in 1999.
If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre