Pertusaria coccodes Cf. forme saxicole.
This form differs from Pertusaria coccodes by growing on rocks or stones, particularly siliceous stones in chapel walls surrounded by trees whose barks shelter Pertusaria coccodes. N.B. On rocks, to be differenciated from Pertusaria pseudocorallina, much more common, whose thallus is more ochre-pink and of which isidia are light brown, base-contracted mace-like shaped, with a dark-brown almost blackish tip, dispersed on all the surface and all the areoles, the thallus being (in principle) K+ yellow turning rapidly to red, Pd+ yellow and KC+ yellow then red or a mixture of both, but whatever characteristics are taken to differenciate those two species on rocks, there will always remain some embarassing in-between specimens.
N.B. Identified here with the usual restrictions because the specimens have only been identified on unreliable macroscopic characters and have not been tested by a DNA analysis technique.