Lepra corallina  

Thallus rather thick, stark white to pale or dark grey, continuous, sometimes rimose-areolate. Prothallus often conspicuous, white. Isidia 0.1-0.3 mm diam., abundant, often covering the thallus, simple, cylindrical or becoming coralloid, erect or ± decumbent and unoriented.
Anamorph: not known.
Teleomorph: fertile warts rare, 1.5-2 mm diam., convex, sharply constricted at the base, often with an uneven to warted upper surface enclosing 2-4 (-11) apothecia. Apothecial disc 0.3-0.5 mm diam., ± expanded, flat or ± convex, pale or dark brown, often faintly white-pruinose. Asci 2-spored. Ascospores 80-140 (-230) × 40-80 μm, the wall 2-3 μm thick, not zoned or striate.
Chemistry: thallus C–, K+ yellow to yellow-orange, KC+ yellow, Pd+ yellow-red, UV– (thamnolic acid).