This evergreen fern grows almost exclusively on vertical
surfaces. The undergrond needs to be calcareous rocks or
a mossy limestone cliff and between the stones of walls.
Wall-rue or Asplenium ruta-muraria
There are a few sporecases on the undersides of the
Ripe spore cases (sori) are brown colored.
When the spores are not ripe they are covered
with a veil (indusium). The veil breaks and
releases the spores, spread by the wind.
This happens during summertime until the mid
of the fall.