Distribution: N - VG (Tretiach 1993), Ven (Lazzarin 2000b), TAA, Lomb, Piem (Isocrono & al. 2004), Lig (S-F145460). C - Marc (TSB 33889), Abr (Jatta 1909-1911). S - Camp (Nimis & Tretiach 2004, Garofalo & al. 2010), Pugl, Si (Nimis & al. 1994, 1995).
Description: Thallus squamulose, homoiomerous, slightly gelatinous when wet. Squamules 1-2 mm wide, brown-black to black, but usually blue-pruinose, with a mostly entire margin, dispersed to usually crowded to form effuse crusts, with an often lobulate to incised margin, covered in soredia- or isidia-like granules. Apothecia 1-2 per squamule, first immersed and urceolate, but soon expanded and clearly lecanorine, 0.3-0.5 mm across, with a dark reddish brown, concave to flat disc, and a thick, rugose, pruinose thalline margin. Epithecium orange-brown, thin; hymenium colourless, 100-150 µm thick, the hymenial gel I+ deep blue; paraphyses monilifrom, 3-4 µm thick, the apical cell slightly swollen and to 5 µm thick; hypothecium pale orange-brown, 20-50 µm high in central part. Asci 8-spored, cylindrical-clavate, thin-walled, with an amyloid apical cap. Ascospores 1-celled, hyaline, broadly ellipsoid to subglobose, 9-15 x 7-10 µm. Pycnidia immersed, globose to pyriform. Conidia hyaline, ellipsoid to narrowly ellipsoid, 2.5-4 x 1.5-2 µm. Photobiont cyanobacterial, chroococcoid, of a few cells surrounded by a gelatinous sheath which is yellowish brown to purple near the thallus surface. Spot tests: all negative. Chemistry: no lichen substances.
Note: on steeply inclined, sunny surfaces of calcareous rocks (mainly limestone, but also calciferous schists and sandstone) with periodical water seepage after rain, below the subalpine belt. Probably widespread throughout the country.