Distribution: N - Frl (TSB 15273). S - Camp (Puntillo & al. 2000, Puntillo 2000), Cal (Puntillo & Vezda 1994, Sérusiaux 1996, Puntillo 1996, 2000).
Description: Thallus crustose, thin and smooth to rarely granulose or slightly verrucose, greenish grey to bluish grey, somehow glossy, forming small, suborbicular patches which eventually merge to cover larger areas, usually delimited by a bluish prothallus. Apothecia biatorine, constricted at base, 0.1-0.2(-0.3) mm across, with a flat to convex, pale brown to bluish grey or bluish black disc, and a thin, whitish, soon excluded proper margin. Proper exciple of vertically arranged hyphae with elliptical to polyhedral cells, up to 15 µm wide laterally, colourless throughout or very pale brown in innermost part; epithecium scarcely differentiated from the hymenium; hymenium colourless, I+ blue; paraphyses branched and anastomosing, 1-1.5 µm thick, forming a densely interwoven network around the ascus tips; hypothecium very thin, dark brown, in central parts K+ greenish brown to green. Asci 8-spored, clavate, with a K/I+ blue apical dome containing a darker blue, tubular ring-structure, and an amyloid coat, Byssoloma-type. Ascospores 3(-5)-septate, hyaline, oblong-fusiform, straight or slightly curved, 16-28(-34) x 3-4 µm. Pycnidia dark grey to blue-black, immersed in the apothecia or sessile on the thallus, with palisadic hyphae or hairs on rim of ostiole (enclosing the conidial mass at least when young), producing (12-)20-45 µm long, thread-like macroconidia, or 4-8 µm long, bacilliform microconidia, respectively. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a mild-temperate to southern boreal-montane lichen found on needles of Abies in very humid montane forests, but also on leaves of Buxus and Laurus in warm-humid gorges near the coast, to be looked for further in the most humid parts of the Alps, on twigs of Picea, and branches of Calluna and Vaccinium. The species 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)