Buellia stellulata

Crustose cracked, saxicolous on siliceous rocks.
Note: thallus K+ yelow later red, reddish-brown hipothecium, spores brown, biseptate, 9-11 x 5-6,5 micras:

White thallus:

Thallus K+:
Lithology: phyllite and andesite
Altitude: 226 and 20 m
Municipality: Mojácar y Níjar