Distribution: N - Lig (Lumbsch 1994, Giordani & al. 2016). C - Tosc, Sar (Rizzi & al. 2011). S - Cal (HAL-19972), Si (Nimis & al. 1996b).
Description: Thallus crustose, episubstratic, irregularly granulose-verrucose, whitish to grey-white, consisting of contiguous to dispersed, rounded or slightly angulose, scabrid warts of different sizes developing on a black hypothallus. Apothecia lecanorine, sessile, round to angular by mutual compression, c. 1 mm across, with a flat to slightly convex, dark red-brown to finally brown-black disc, a thin, entire, grey, finally often excluded thalline margin and a usually well-evident, grey proper margin forming a raised parathecial ring. Thalline exciple corticate, with numerous small crystals dissolving in K; proper exciple thick, spottily blackish, the pigmented parts N+ red (this character may be due to the presence of a parasite), with crystals soluble in K; epithecium red-brown to orange-brown, the pigment not dissolving in K, without crystals; hymenium colourless; paraphyses coherent, simple or sparingly branched, the apical cells clearly swollen; hypothecium colourless. Asci 8-spored, clavate, very thin-walled, with a K/I+ blue, tall tholus penetrated by a faintly amyloid apical cushion, the wall K/I-, surrounded by a blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, oblong-ellipsoid, 11-15 x 4-6 µm. Photobiont chlorococcoid. Spot tests: thallus K+ yellow, C-, KC-, P- or P+ pale yellow. Chemistry: atranorin, 2-0-methylperlatolic acid.
Note: on coarse-textured, basic siliceous rocks at low elevations. The sample from Calabria was collected by B. Feige near Briatico, on granite.