Distribution: N - Lomb (S-F99329, De Vita & Valcuvia 2004), Piem (Valcuvia 2002, 2002b), Emil (TSB 35572), Lig (GDOR 1020). C - Tosc, Laz, Sar (Rizzi & al. 2011, Giordani & al. 2013).
Description: Thallus crustose, episubstratic, consisting of scattered to contiguous, angular, 0.2-0.5 mm wide, 0.1-0.3 mm thick, epruinose, slightly concave, dark brown areoles with a raised, often wavy, black margin, forming up to 6 cm wide patches. Cortex paraplectenchymatous, (10-)15-40 µm thick, brown in upper part, colourless in lower part; algal layer more or less continuous, but usually uneven; medulla white, prosoplectenchymatous. Apothecia rounded, 0.1-0.5 mm across, immersed in the areoles, usually one per areole, with a dark brown disc, a poorly evident thalline margin, and sometimes a concentric, thin parathecial ring. Proper exciple c. 10 µm thick; epithecium brown, c. 10 µm high; hymenium colourless, 50-100 µm high; paraphyses coherent, (1.3-)1.5-2.1 µm thick at base, the apical cells usually not markedly expanded; hypothecium colourless, 15-60 µm high. Asci c. 100-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, ellipsoid, (3-)4-5.5 x 1.5-1.7(-2.2) µm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV- . Chemistry: without lichen substances.
Note: a probably Mediterranean-Atlantic species of siliceous rocks wetted by rain, reaching the montane belt in dry-continental areas (e.g. in the Alps).