Distribution: N - Frl (Tretiach & Hafellner 2000), TAA, Lomb (De Vita & Valcuvia 2004, Delucchi & Valcuvia 2004, Valcuvia & al. 2003), Piem (TSB 34356), VA (Piervittori & isocrono 1999, Matteucci & al. 2013, 2015c).
Description: Thallus crustose, episubstratic, white, grey, yellowish grey or ochraceous, rimose to verrucose-areolate, rather thick, often forming very large patches, usually delimited by dark prothallus. Cortex 20-40 µm thick, paraplectenchymatous with elongated cells, sometimes covered by a thin epinecral layer; medulla white, I+ pale blue. Apothecia aspicilioid-cryptolecanorine, immersed in the thallus to subsessile, 0.2-1.8 mm across, with a slightly concave to convex, black, rarely slightly pruinose disc, and a thin, irregular pseudothalline margin which is often replaced by a black proper margin. Proper exciple poorly developed, brownish black in outer part, colourless within; epithecium olive-green to green-black, N+ green; hymenium colourless, up to 130 µm high, I+ blue; paraphyses simple to branched and anastomosing in upper part, up to 2 µm thick, the apical cells not or only slightly swollen; hypothecium colourless or pale yellow, c. 60 µm high. Asci 8-spored, clavate, apically thickened, indistinctly I+ blue in lower outer part of tholus. Ascospores 1-celled, hyaline, broadly ellipsoid, 10-20 x 7-11 µm, the wall I-. Pycnidia immersed, the wall green-black in upper part, otherwise colourless. Conidia short-bacilliform, 4.5-8 x c. 1 µm. Photobiont chlorococcoid. Spot tests: thallus K + yellow turning red (needle-like crystals), C-, KC-, P+ yellow-orange. Chemistry: norstictic and connorstictic acids.
Note: a mainly arctic-alpine, circumpolar species found on crystalline schists and acid siliceous rock, mostly near and above treeline; in Italy probably restricted to, and more widespread in the Alps. For the record from South Tyrol see Nimis (1993: 103-104). Here I also place some records of Aspicilia intermutans from alpine-subalpine situations (see note on that species).