Distribution: N - VA (Piervittori & Isocrono 1999).
Description: Thallus crustose, episubstratic, pale glaucous grey, 0.2-0.35 mm thick, rimose-areolate, poorly delimited. Areoles small, 0.4-0.7 mm wide, angular, flat to subconvex. Cortex 15-25 µm thick; medulla white to grey, I-. Apothecia lecanorine-aspicilioid, 0.2-0.4 mm across, angular in outline, immersed in subconvex areoles, 1-2 per areole, with a black, at first slightly white-pruinose, concave to flat disc, and a thin thalline margin. Epithecium olive-green; hymenium colourless, 90-100 µm high, I+ pale blue, then reddish; paraphyses coherent, c. 1.7 thick at base, the apical cells moniliform, 3-3.5 µm wide; hypothecium colourless, 50-100 µm high. Asci 8-spored, broadly clavate, the thin outer coat K/I+ blue, the wall and apical dome K/I-. Ascospores 1-celled, hyaline, ovoid, 14-19 x 10-12 µm. Pycnidia black, immersed, with a pale wall. Conidia thread-like, slightly curved, 24-27 x 0.8-0.9 µm. Photobiont chlorococcoid. Spot tests: cortex K-, C-, KC-, P-; medulla K+ yellow (reaction to be observed on sections under the microscope). Chemistry: unknown, probably with stictic acid in the medulla.
Note: a very poorly known taxon described from the Aosta Valley. It is similar to A. valpellinensis, but has smaller spores. Indicator values are tentative.