Distribution: C - Tosc (Tretiach & al. 2008). S - Camp (Garofalo & al. 2010), Cal (UPS-L111515). Si (Iacolino & Ottonello 2006).
Description: Thallus crustose, thinly episubstatic, continuous to rimose-areolate, grey to almost black, turning greenish when wet, often delimited by a thin, dark prothallus, or inapparent and appearing as a small, dark stain. Areoles, when developed, scattered 0.15-0.25 mm wide, flat to slightly convex, smooth. Apothecia lecideine, round, black (the disc turning brown when wet), 0.1-0.2(-0.3) mm across, sessile and constricted at base, with a flat to finally convex disc and a thin, raised, finally sometimes excluded proper margin. Proper exciple green-black throughout, N+ violet; epithecium dark brown to green-black, 5-10 µm high, N+ violet; hymenium colourless, 30-40(-45) µm high, I+ blue turning reddish; paraphyses simple or sparingly branched in upper part, lax, 1.5-2 µm thick at base, the apical cells capitate, up to 5 µm wide, with a dark brown to black cap; hypothecium colourless, 25-50 µm high. Asci 8-spored, cylindrical-clavate, with a K/I+ blue outer coat and a K/I+ uniformly blue apical dome, Catillaria-type. Ascospores 1-septate, hyaline, olblong-ellipsoid to ovoid, 7-12(-15) x 2-4 µm. Photobiont chloroccocoid, the cells 7-19 µm wide. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: an inconspicuous lichen found on steeply inclined surfaces of hard siliceous rocks in humid situations, mostly in upland areas; very much overlooked and certainly more widespread in Italy.