Distribution: N - TAA (Bungartz 2004), Lig (Bungartz 2004, Giordani & al. 2016). C - Tosc, Sar (Scheidegger 1993).
Description: Thallus crustose, episubstratic, areolate, shiny, brown to dark brown, but the areoles often with narrow whitish margins; cortex of anticlinally oriented hyphae, the terminal cells with brown caps and clearly swollen; medulla white, not amyloid, I-. Apothecia black, cryptolecanorine, 0.2-0.4 mm across, innate, with a flat to convex disc. Proper exciple thin, dark brown to brown-black in outer part, colourless within, N-, aethalea-type; epithecium brown; hymenium colourless, without oil droplets, 40-65 µm high; hypothecium pale brown. Asci 8-spored, Bacidia-type. Ascospores 1-septate, brown, broadly ellipsoid, not constricted at septum, 9-11 x 5-5-7 µm, Buellia-type, with a psilate ornamentation. Photobiont chlorococcoid. Spot tests: thalllus K+ yellow turning red (crystals), C-, KC-, P-. Chemistry: norstictic acid with connorstictic acid.
Note: on siliceous rocks in dry-warm areas, related to B. fusca, but chemically different, occurring both in the Mediterranean area and in dry-continental Alpine valleys.