Synonyms: Aspicilia desertorum auct. p.p. non (Kremp.) Mereschk.; Aspicilia esculenta auct. p.p. non (Pall.) Flagey
Distribution: C - Abr (Nimis & Tretiach 1999).
Description: Thallus crustose, episubstratic, up to 2.5 mm thick, verrucose-areolate, the areoles strongly convex, sometimes bullate, rounded or irregular, (0.5-)1-2.5(–3.5) mm in diam., contiguous and separated by deep cracks, brown to olive-brown, dull, without a distinct prothallus. Cortex brown in uppermost part, covered with an epinecral layer or crystals; algal layer arranged in glomerules interrupted by hyphal tissue, especially in the thalline margin of apothecia; medulla white, thick, I-. Apothecia lecanorine-aspicilioid, at first immersed and apparing as white-pruinose orbicular dots, then sessile and sometimes constricted at base, (0.2-)0.4-1.4(-1.8) mm across, 1(-3) per areole, round to elongated or irregular, with a concave to finally flat, black, often thinly white-pruinose disc and a thick thalline margin which is elevated and prominent in older apothecia, and often has a white- to grey-pruinose, thin rim in inner part. Epithecium olive-brown to brown, with crystals, N+ green, K+ brown; hymenium colourless, I+ persistent blue; paraphyses submoniliform to moniliform, 1.5-2 μm thick in lower part, the uppermost cells subglobose, 4-5.5 μm wide; subhymenium and hypothecium colourless, I+ persistently blue. Asci 2-4-spored, clavate, the thin outer coat K/I+ blue, the wall and apical dome K/I-. Ascospores 1-celled, hyaline, globose to subglobose, 24-28 x 18-28 μm. Pycnidia immersed, with a black, puctiform ostiole usually surrounded by a white rim. Conidia thread-like, straight. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a xeric subtropical lichen of steeply inclined, hard, more or less calciferous rocks and dolomite, limited to the oromediterranean belt in Italy, and probably absent from the Alps. The taxonomy of this group is still unsettled (Owe-Larsson & al. 2011): saxicolous crustose forms formerly called Aspicilia desertorum, including the Italian samples, belong to the Circinaria elmorei-complex, which is presently under revision (Sohrabi, in litt.).
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)