Distribution: N - VG, Frl, Ven (Lazzarin 2000b, Thor & Nascimbene 2007), TAA (Nascimbene & al. 2007b), Lomb, Piem, VA (Piervittori & Isocrono 1999), Emil (Fariselli & al. 2020), Lig. C - Tosc (Tretiach & al. 2008), Umb (Panfili 2007). S - Cal (Puntillo 1996).
Description: Thallus crustose, whitish to grey-green, continuous, mostly small-granulose to verrucose. Apothecia frequent, without a thalline margin, sessile and constricted at base, 0.4-1.3 mm across, with grey, dark reddish brown to blackish brown, long concave to flat disc which becomes convex in old apothecia, the margin thin but evident in young apothecia, persistent, only finally excluded, smooth, concolorous with or paler than disc, often somehow shiny. Proper exciple colourless or patchily reddish brown, 65-95 µm wide laterally; epithecium brownish to olive-brown, K-, N-; hymenium colourless, 70-100 µm high; paraphyses simple, slightly thickened above, conglutinate, <2 µm thick; hypothecium pale to reddish brown in upper part. Asci 8-spored, clavate, with a I+ blue tholus and an internal, darker I+ tubular structure, the external gel I+ faintly blue, Biatora-type. Ascospores (0-)3-septate, hyaline, ellipsoid-cylindrical to fusiform, 15-27 x 5-8 µm, without a distinct perispore. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on mosses and plant debris on calcareous substrata, sometimes on bark, especially on basal parts of old trunks in open forests, and on other lichens (e.g. Peltigera); most frequent in the Alps, but reaching south along the Apennines to the mountains of Calabria.