Distribution: N - TAA (Gaya 2009), Lomb (Gaya 2009), Piem (TSB 32816), Lig (Gaya 2009). C - Sar (Herb. Vondrák 9616).
Description: Thallus crustose-placodioid, forming orbicular rosettes to 7 mm in diam., ochraceous orange to reddish-orange, not pruinose. Central part of thallus with 0.3-1.3 mm wide, flat to weakly convex, irregular to elongate areoles formed by lobe fragmentation. Marginal lobes convex, irregular or finger-like, slightly broadening at tips, not or rarey forked, 0.1-1 mm long, 0.1-0.6 mm wide. Upper cortex with a 5.5-18(-22) μm thick brownish-orange upper layer, and a hyaline (6-)10-40(-47) μm thick intemal layer; medulla lax to compact. Apothecia common, highly variable, pseudolecanorine or lecanorine, more or less crowded, 0.1-1.1 mm across, round or slightly deformed by mutual compression, located either on the areoles or on the lobe bases, sessile to constricted at base. Disk flat to strongly convex, concave in young apothecia, reddish-orange to brownish, smooth. Margin lighter than disk, without differentiation between proper and thalline margin, smooth, 30-100 μm thick. Epithecium 6-8(-10) μm thick, brownish-orange K+ red; hymenium, subhymenium and hypothecium colourless; paraphyses distinctly septate, forked or subapically branched, often anastomosing, 1.5-3 μm thick at base, with the last apical cell swollen and 3-7.5 μm wide. Asci 8-spored, clavate, functionally unitunicate, apically thickened with a broad internal beak, the inner part of apex and external cap I+ blue, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, broadly to narrowly ellipsoid, (7-)8.5-11.5(14.5) x (3.5)4-5(5.5) μm; the septum (1.8-)2.5-4(-5) μm, (1.4-)1.7-2.5(-3.6) times as long as wide. Photobiont chlorococcoid. Spot tests: thallus and apothecia K+ red, C-, KC-, P-. Chemistry: thallus and apothecia with parietin (major), fallacinal, emodin, teloschistin and parietinic acid (minor), corresponding with chemosyndrome A of Søchting (1997).
Note: a very polymorphic taxon (see Roux & coll. 2014) with a mainly temperate to boreal distribution in Europe, also known from the southern European mountains, most frequent on base-rich siliceous rocks or on decalcified calcareous rocks, usually in nutrient-poor stands, both on vertical walls of cliffs and overhangs and on horizontal surfaces of siliceous boulders; especially the southern populations seem to prefer rather shaded conditions. The sample from Sardegna was collected in the Gennargentu Massif near Fonni, on the northern slopes of Mt. Monte Spada, at c. 1450 m. The name is often spelled “obliterata”, but the term “oblitteratus” used in the basionym is good Latin and does not need any correction.