in Frolov & al., J. Syst. Evol. 59, 3: 468, 2020. Basionym: Lecidea atroflava Turner - Trans. Linn. Soc. London, 9: 142, 1808.
Synonyms: ? Caloplaca cerinoides (Anzi) Jatta non sensu Nimis; ? Placodium cerinoides Anzi; Caloplaca atroflava (Turner) Mong.; Caloplaca atroflava var. submersa (Nyl.) H. Magn.; Caloplaca ferruginea var. obscura Th. Fr.; Caloplaca turneriana (Ach.) H. Olivier; Lecanora pyracea f. submersa Nyl.; Pyrenodesmia atroflava (Turner) S. Y. Kondr.
Distribution: N - Lomb, Lig. C - Sar (Rizzi & al. 2011). S - Camp (Nimis & Tretiach 2004), Cal (Puntillo 1996). S - Si (Caniglia & Grillo 2003, Grillo & Caniglia 2004).
Description: Thallus crustose, episubstratic, dark grey to grey-brown, sometimes almost black, rimose-areolate, often delimited by a fimbriate dark prothallus, smooth or blastidiate in some forms. Apothecia adnate to sessile and slightly constrictd at base, 0.3-0.8 mm across, with a flat, epruinose, orange to olive-orange disc (tending to blacken in old apothecia) and a yellow-orange, persistent proper margin, which is sometimes surrounded by an incomplete thalline margin at the base. Proper exciple of radiating hyphae, orange-brown in outer part, colourless within; epithecium orange, K+ red or K+ violet, N + violet, C-; hymenium colourless, 50-70 µm high; paraphyses simple or sparingly branched, the apical cells slightly swollen; hypothecium colourless. Asci 8-spored, cylindrical-clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, broadly ellipsoid, 10-17 x 5.5-10 µm, the septum 4-7 µm thick. Spot tests: thallus K- or K+ faintly violet, C-, KC- P-, N+ violet; apothecia K+ red, C-. Chemistry: non-chlorinated anthraquinones in apothecia (C- in section), Sedifolia-grey pigment in thallus.
Note: a Mediterranean-Atlantic species in Europe, found on base-rich or eutrophicated siliceous rocks, especially on basalt, sometimes periodically submerged in Mediterranean creeks and rivulets, or on exposed surfaces of boulders near the soil surface.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)