Synonyms: Biatora emergens Müll. Arg.; Haplocarpon lithospersum (Zahlbr.) M. Choisy; Lecidea dissipata H. Magn.?; Lecidea elata var. violascens Lynge; Lecidea jurana auct. ital. p.p. non Schaer.; Lecidea lithospersa Zahlbr.; Lecidea murina Ach.; Lecidea platycarpa var. apyospora A. Massal.
Distribution: N - Frl, Ven (Caniglia & al. 1999, Lazzarin 2000b), TAA (Hertel 2001, Nascimbene 2008b, Hertel & Schuhwerk 2010), Lomb, Piem, Emil (Fariselli & al. 2020). C - Abr (Gheza & al. 2021).
Description: Thallus crustose, mostly endosubstratic and pale blue-green, rarely thinly episubstratic, continuous to finely rimose and chalky white, without a distinct prothallus. Medulla white, mostly I+ pale blue. Apothecia lecideine, black, epruinose and somehow shiny, adnate and constricted at base, 0.6-2.5(-3.5) mm across, when young with a flat disc and a prominent, wavy proper margin, later progressively immarginate, with a strongly convex, cracked to cerebriform disc whose parts separate and sometimes give rise to new apothecia. Proper exciple thick, black in the thin outer rim, otherwise darker red-brown in inner part, paler in outermost part, K+ reddish violet; epithecium bright blue-green; hymenium colourless or blue-green in upper part, brownish in lower part, 70-90 µm high; paraphyses strongly coherent, branched and anastomosing, 2-2.5 µm thick at mid-level, the apical cells to 5 µm wide; hypothecium red-brown, K+ reddish, darker than exciple. Asci 8-spored, clavate, with a I+ pale blue tholus and a central amyloid tube, approaching the Porpidia-type. Ascospores 1-celled, hyaline, ellipsoid with slightly pointed tips (lemon-shaped), 11-17(-21) x 5-9 µm, halonate at least when young. Pycnidia globose, immersed. Conidia bacilliform to slightly flask-shaped, 4-8 x 1.4-1.7 µm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: an arctic-alpine, incompletely circumpolar species found on limestone and dolomite in upland areas, common in the Alps; the distinction from F. jurana is not always easy. All records from southern Italy cited in Nimis (1993: 295), being dubious, are not accepted here.
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)