Acarospora fuscata

Acarospora fuscata ("brown cobblestone lichen") is a glossy pale or yellowish-brown areolate lichen with angular areolas that grows up to 10 cm (4 in) wide on non-calcareous rock in low and high elevations.: 217  It grows in Europe and North America. It grows in southern California and on the eastern part of the Sierra Nevada range.: 217  It may grow with the areolas disconnected.: 217  The areolas may lift at the edges, but the areolas do not overlap like true squamules (sub-squamulose).: 217  More common in the Sierras is the similar species Acarospora thamnina, which is truly squamulose with overlapping scales.: 217  It usually has 0-1 apothecium per areole, which may be point-like (punctiform) or fill the entire areole with a disc that is rough surfaced and reddish brown. The asci are club shaped (clavate), with over 100 spores. Lichen spot tests are K−, C+ vaguely pink, KC+ red, and P−.: 217  Secondary metabolites include gyrophoric acid....read more on Wikipedia.