Distribution: N - Lomb (S-F99329, De Vita & Valcuvia 2004), Piem (Valcuvia 2002, 2002b), Emil (TSB 35572). C - Tosc, Laz, Sar (Rizzi & al. 2011, Giordani & al. 2013).
Description: Thallus crustose, episubstratic, consisting of scattered to contigugous, angular, 0.2-1 mm wide, 0.1-0.3 mm thick, epruinose, slightly concave, dark reddish brown areoles with a raised, often wavy, black margin. Cortex paraplectenchymatous, 15-40 µm thick, brown in upper part, colourless in lower part; algal layer more or less continuous; medulla white, prosoplectenchymatous. Apothecia rounded, 0.2-0.8 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 proper margin. Parathecium c. 10 µm thick; epithecium brown; hymenium colourless, 50-90 µm high; paraphyses coherent, (1.3-)1.5-2.5 µm thick at base, the apices usually not markedly expanded; hypothecium colourless. Asci c. 100-spored, clavate, the apical dome K/I-. Ascospores 1-celled hyaline ellipsoid, (3-)4-5.5 x (1.5-)2-2.5 µm. Photobiont chlorococcoid. Spot tests: thallus 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).