Description: Thallus crustose, episubstratic, areolate, pale yellowish brown to brown, somehow shiny, the areoles subsquamulose, weakly convex with reflexed margins, (0.2)-0.4-0.7(-1.3) mm wide, contiguous to usually scattered. Medulla white, I-. Apothecia abundant, often located at the margins of the areoles, lecideine, glossy black, circular in outline, 0.2-0.8(-1.3) mm across, with a flat disc and a very thin proper margin. Proper exciple blackish; epithecium bluish green or green; hymenium colourless or greenish in upper part, 25-37 μm high; paraphyses coherent; hypothecium colourless. Asci 8-spored, narrowly clavate, thick-walled, with a K/I+ pale blue tholus and a strongly amyloid, thin apical cushion, surrounded by a I+ blue outer layer, Lecidea-type. Ascospores 1-celled, hyaline, ellipsoid, 5-7.3(-8.5) x 2.5-3(-3.6) μm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C- KC-, P-, UV-. Chemistry: without lichen substances.
Note: on low siliceous outcrops, pebbles and tiles at low elevations; widespread in Europe but rarely collected, with a single record from the Eastern Alps (Austria); to be looked for in Italy.