Description: Thallus crustose, episubstratic, minutely areolate, without a distinct prothallus, forming patches of a few cm in diam. Areoles 0.4-0.6(-1) mm wide, contiguous, rounded to irregular, flat to usually convex, deep brown to reddish brown, pale and ecorticate in lower part, epruinose. Apothecia lecanorine, 0.1-0.4 mm across, rounded, 1-3 per areole, immersed, with a dark brown, usually flat disc, and a usually paler brown, raised, smooth thalline margin, tending to become pseudogyrose when old. Epithecium yellowish brown; hymenium colourless, 85-100 µm high, paraphyses 15-1.7 µm thick, the apical cells capitate and 3-4 µm wide; hypothecium colourless, c. 20 µm high. Asci 100-200-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, narrowly ellipsoid, 3-5 x 1.5-1.7 µm. Photobiont chlorococcoid. Spot tests: thallus and medulla K-, C-, KC-, P-, UV-. Chemistry: no lichen substances.
Note: a poorly known species of eutrophicated, dry and hard lignum, closely related to, and possibly a synonym of other saxicolous species of the A. nitrophila complex. Hitherto reported from Scandinavia and the Alps. A dubious record from Campania by Garofalo & al. (1999) is not accepted here.