Distribution: N - TAA (Nascimbene & al. 2007b, Nimis & al. 2015), Lomb, Emil (Fariselli & al. 2020). C - Mol (Paoli & al. 2015). S - Camp (Nimis & Tretiach 2004).
Description: Thallus crustose, episubstratic, continuous, rimose or finely warted-areolate, whitish to grey or yeIlowish grey. Apothecia lecideine, (0.4-)0.6-0.8(-1.2) mm across, brown-orange to purplish brown, often darkening with age, with a flat to finally convex, epruinose or white-pruinose disc, and a concolorous or slightly darker, at first thick and raised, finally excluded proper margin. Proper exciple 45-95 μm wide laterally, without crystals or with radiating clusters of minutc crystals, pale yellowish brown, orange-brown to dark brown, K+ purple-red in outer and upper parts, often slightly paler within and colourless in lower parts; epithecium pale brown, scarcely differentiated from the hymenium; hymenium (56-)63-94(-100) μm high, colourless or very pale brown-orange in lower part, the upper part concolorous or (rarely) deep brown-orange; paraphyses 1-1.6 μm thick at mid-level, the apical cells not thickened or up to 3 μm wide; hypothecium brown-orange to dark brown, darker than exciple. Asci 8-spored, cylindrical-clavate, surrounded by a gelatinous I+ blue coat, with a well-developed I+ blue tholus, a I+ darker blue tube and a well-developed ocular chamber, Bacidia-type. Ascospores (3-)7-15-septate, hyaline, acicular, straight to sigmoid, (38-)43-57(-74) x (2-)3-4(-5) μm. Pycnidia immersed, pale brown around the ostiole. Conidia simple, filiform, curved, 10-17 x 0.6-0.8 μm. Photobiont chlorococcoid, the cells 5-12 μm in diam. Spot tests: thallus K-, C-, KC-, P-, UV-; pigmented parts of apothecia K+ purple-violet, N-. Chemistry: thallus without lichen substances or with traces of atranorin; apothecia with the Bacidia-brown and Rubella-orange pigments.
Note: a mild-temperate to tropical species found on broad-leaved trees in open, humid forests. It is included in the Italian red list of epiphytic lichens as “Endangered” (Nascimbene & al. 2013c).
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)