Distribution: N - TAA, Lomb, Piem (Favero-Longo & al. 2015), VA (Piervittori & Isocrono 1999), Lig (Lazzarin 2000b). C - Tosc, Laz, Sar (Scheidegger 1993, Rizzi & al. 2011). S - Camp (Nimis & Tretiach 2004, Garofalo & al. 2010), Pugl (TSB 7645), Bas, Cal (Puntillo 1996), Si (Grillo & Caniglia 2004).
Description: Thallus crustose, episubstratic, rimose, whitish, forming small orbicular patches to 1 cm in diam.; medulla white, not amyloid, I-. Apothecia black, cryptolecanorine to lecideine, 0.1-0.3 mm across, innate, with a flat to convex disc and a thin, finally excluded proper margin. Proper exciple very thin, aethalea-type, the inner hyphae hyaline, prosoplectenchymatous, the outer hyphae parallel and usually strongly pigmented; epithecium olive-green to olive-brown, N+ reddish; hymenium colourless, without oil droplets, 45-70 µm high; hypothecium dark brown. Asci 8-spored, clavate to cylindrical-clavate, the apical dome K/I+ dark blue with a pale, conical-pointed apical cushion (axial mass), the wall I-, but the thin outer gel I+ blue, Bacidia-type. Ascospores 1-septate, brown, oblong, not constricted at septum, 10-13 x 5-6 µm, Buellia-type, with a rugulate ornamentation, rarely smooth, especially when young. Pycnidia flask-shaped, black, immersed in thallus. Conidia bacilliform, 3.5-5 µm long. Photobiont chlorococcoid. Spot tests: thallus K+ yellow, C-, KC-, P- or P+ faintly yellow. Chemistry: atranorin, confluentic and 2'-O-methylperlatolic acids.
Note: a mild-temperate to subtropical lichen found on calciferous and base-rich, hard siliceous rocks (e.g. on basalt), both near the coast in Mediterranean Italy, and in dry-warm Alpine valleys.