Caloplaca lucifuga  

Thallus immersed in bark, inconspicuous, or a thin, grey film. Soralia numerous, pale yellow to dirty orange-brown, often very crowded and contiguous, flat and ulcer-like, becoming convex, rounded. Soredia farinose.
Anamorph: no information available.
Teleomorph: unknown.
Chemistry: thallus K–, soralia K+ purple.