Distribution: N - Ven (TSB 2024), TAA, Lomb, Piem (Giordani & al. 2014), VA (Piervittori & Isocrono 1999), Lig (Hertel 2001). C - Tosc (Hertel 2001), Sar (Nöske 2000). S - Cal (Puntillo 1996), Si (Nimis & al. 1996b).
Description: Thallus crustose, endosubstratic and not evident (but the fimbriate dark prothallus sometimes quite evident), more rarely episubstratic and consisting of dispersed, greyish–white, irregular to roundish, 0.2–0.6(-0.7) mm wide, flat to irregularly convex areoles. Medulla I-. Apothecia lecideine, black, sessile and strongly constricted at base, round to irregular in outline, 0.4-1.5(-2.2) mm across, often clustered, with a slightly concave to slightly convex, rarely faintly pruinose disc, and a raised, often wavy, shiny, persistent proper margin. Proper exciple with a dark purple-black outer rim and a grey to pale reddish medullary zone inspersed with crystals, C-; epithecium dark reddish violet to olivaceous brown; hymenium pale reddish purple, K+ violet, 30-50(-60) µm high; paraphyses simple or sparingly branched and anastomosing in upper part, the apical cells to 4 µm wide; hypothecium dark brown to brown-black, (50-)80–180(-300) μm high. Ąsci 8-spored, clavate, the outer coat I+ blue, the apex thickened, with a I+ blue tholus, Lecidea-type. Ascospores 1-celled, hyaline, oblong-ellipsoid, (7-)9-12(-14) x 2.5-4 µm, 2.4-4.4 times as long as wide. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances or with traces of terpenoids.
Note: on exposed, steeply inclined faces of non-calcareous, mineral-rich rocks in lichen-poor communities, with a wide altitudinal range. The world distribution was mapped by Hertel (2006). The record from Venezia Giulia in Nimis (1993: 389), being far outside the present Italian border, is not accepted here.