Pertusaria flavicans Lamy

    Thallus crustose, more or less thick, uneven, rimose, verrucose, cracked and areolate, areoles slightly angular, 1 mm across, flat to slightly convex, yellow, yellowish, yellow-greenish, grey-greenish, soralia towards areole margins, yellow-greenish, paler than the thallus. Apothecia rare, hardly visible, or ostiole-like with a thick exciple. Ascospores ellipsoid, 60-75 x 20-30 µm. C+ orange, K-, KC+ orange, Pd-, UV+ bright orange. Oceanic trends, but not exclusively, on weakly acid siliceous rocks. Not to be confused with Pertusaria pluripuncta which grows on very exposed rocks, has a thicker thallus, more verrucose, not sorediate and Pd+ orange, C+ orange.*