Rhizocarpon simillimum

Crustose rimose-aerolate, saxicolous, on siliceous rocks.
Note: medulla I+ blue, hypothecium dark brown, spores soon dark black-graybrown, 1-septate, 11-16 x 5-8 µm:

Lithology: andesite
Altitude: 100 m
Municipality: Níjar