Polyblastia murorum B. de Lesd.

Syn.: incl. Polyblastia murorum B. de Lesd. var. denudata B. de Lesd.
Lichenised. Poorly known taxon.
Substrate: calciferous rocks
Altitudinal distribution: submediterranean/colline belt (potential vegetation: mixed deciduous forests dominated by Quercus and Carpinus)
Note: a species with a whitish-grey, rimose to areolate thallus with very small areolae, entirely immersed perithecia leaving pits after they have fallen out, and broadly ellipsoid, muriform ascospores; on calcareous walls at low elevations in the northern Mediterranean region, with a single record from a wall near Nice (France).
France: Alpes-Maritimes;