in Frolov & al., J. Syst. Evol. 59, 3: 468, 2020. Basionym: Caloplaca fuscoatroides J. Steiner - Verh. zool.-bot. Ges. Wien, 69: 69, 1919.
Distribution: N - Emil (Fariselli & al. 2020), Lig (Herb. Vondrák 10799). C - Tosc, Laz (Genovesi & al. 2011, Roccardi & al. 2014), Sar (Rizzi & al. 2011, Frolov & al. 2020). S - Cal (Herb. Vondrák 10762), Si.
Description: Thallus crustose, episubstratic, dark grey to almost black, rimose or usually areolate, 0.1-0.35 mm thick, the marginal areoles larger and almost subsquamulose, sometimes delimited by a black prothallus. Cortex thin, paraplectenchymatous, the upper part grey, K+ violet; medulla poorly developed. Apothecia zeorine, rust-red but tending to turn lead-grey to blackish, 0.3-1.5 mm across, with a flat to finally convex disc, and a raised, persistent, concolorous or paler proper margin. Proper exciple prosoplectenchymatous; epithecium orange-brown, K+ red, C+ purple (in section); hymenium and hypothecium colourless; paraphyses slightly swollen at apices. Asci 8-spored, clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, ellipsoid, 13-18 x 7-10 µm. the septum 3.5-8 µm thick. Pycnidia dark grey to black, the wall K+ violet. Conidia bacilliform. Photobiont chlorococcoid. Spot tests: thallus K+ violet, C-, KC-, P-; apothecia K+ red, C+ purple (reactions best visible on thick sections under the microscope). Chemistry: Sedifolia-grey pigment in thallus and pycnidia; chlorinated anthraquinones in both disc and margin of apothecia (always with fragilin and without citreorosein and emodinal).
Note: a widespread Mediterranean lichen found on base-rich siliceous rocks wetted by rain. The sample from Calabria was collected at Melito di Porto Salvo, Riaci Capo, on sandstone, that from Liguria near Levanto, Vernazza.