Description: Thallus crustose, thin and often poorly evident, whitish, greyish or ochre-coloured, continuous or slightly cracked, smooth, rarely delimited by a dark prothallus. Apothecia lecideine, rounded to slightly irregular in outline, black, 0.5-1.5(-2) mm across, sessile, slightly constricted at base, with a flat, at first grey-green-pruinose, later epruinose disc, and an epruinose, persistent, prominent, more or less crenulate proper margin. Proper exciple brown-black; epithecium brownish, granulose, the granules K+ yellow-red; hymenium colourless, 60-120 µm high, I+ reddish, K/I+ blue; paraphysoids 1.5-2 µm thick, not anastomosing, the apical cells 4-5 µm wide, with a dark brown cap; subhymenium brownish in lower part, colourless in upper part, 25-40 µm high; hypothecium brown-black. Asci 8-spored, cylindrical to cylindrical-clavate, thick-walled, fissitunicate, with an amyloid ring-structure and a small ocular chamber. Ascospores (4-)5-septate, hyaline, cylindrical-fusiform with pointed ends, often curved, 17-27 x 4-7 μm, thick-walled. Pycnidia rather rare, mostly arranged in lines or clusters, black, half-immersed to sessile. Conidia short-bacilliform, 3.5-4.5 μm long. Photobiont trentepohlioid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a mild-temperate lichen found on bark of old deciduous trees (mainly oaks) in rain-protected faces, more rarely on rock, in very open, humid, park-like woodlands. The specimen from Lombardia was collected on rock. The species is included as “Regionally Exctinct” in the Italian red list of epiphytic lichens (Nascimbene & al. 2013c).
Growth form: Crustose
Substrata: bark and rocks
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)