Distribution: N - Frl (Ekman 2014), Emil (Fariselli & al. 2020), Lig (Lazzarin 2000b, Ekman 2014).
Description: Thallus crustose, thinly episubstratic, pale green to grey-green, finely warted-areolate. Apothecia lecideine, 0.2-0.5 mm across, round to irregular in outline, with a flat to convex, epruinose, beige-brown to black, often piebald disc, and a concolorous or darker, often shiny, finally sometimes excluded proper margin. Proper exciple 34-60 μm thick, without crystals, dark red-brown or blackish green, with a mixture of a red-brown (K+ purplish, N+ orange-red) and a sordid green pigment (K+ intensifying green, N+ purple, with the precipitation of blue crystals), consisting of radiating hyphae with thick gelatinous walls, the terminal cells up to 5 μm wide; hymenium 45-65 μm high, colourless in lower part, the upper part with varying amounts of a green pigment often concentrated into vertical streaks; paraphyses abundant, 1.2-1.7 μm thick at mid-level, simple or sparingly branched in upper part, rarely anastomosing, the apical cells to 4.7 μm wide; hypothecium coloured like the exciple, but much paler. Asci 8-spored, clavate, surrounded by a gelatinous I+ blue coat, with a well-developed I+ blue tholus, a I+ darker blue tube and a well-developed ocular chamber, Bacidia-type. Ascospores 3-septate, hyaline, short-bacilliform to fusiform, straight or slightly curved, 11-19 x 2.5-4 μm. Pycnidia semi-immersed, the wall with a red-brown (K+ purplish, N+ orange-red) pigment around the ostiole. Conidia simple, more or less curved, 8-16 x c. 1 μm, the cells 5-12 μm in diam. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-. Chemistry: thallus without lichen substances.
Note: on calcareous rocks, sometimes in anthropogenic settings (e.g. on mortar and concrete); currently known only from low or moderate elevations in northern Italy, but likely to be more widespread in the Mediterranean Region (see Ekman 2014).