Picture taken on the 8th December 2007 at Sant Marçal ermitage, Montseny, Barcelona, Catalonia, Spain, on granite, exposed, nitrophilous place, 1000 m. altitude aprox.
A very common species in Catalonia, upland, on acid rocks and seepage tracks.
Crustose lichen, thallus faint bluish, thick, areolate,slightly rough surface, with black prothallus. Lecanorine apothecia from immersed to sessile. Disc black, not pruinose.