Distribution: N - Frl (Tretiach & Hafellner 2000), Ven (Nimis 1994, Nascimbene & Caniglia 1997, 2003c, Caniglia & al. 1999, Lazzarin 2000b, Nascimbene 2011), TAA (Caniglia & al. 2002, Nascimbene 2005b, 2006c, 2008b, Nascimbene & al. 2005, 2006, 2007b, 2008c, 2022, Lang 2009), Lomb, Piem (Isocrono & al. 2004, 2006), VA (Piervittori & Isocrono 1999), Emil (Fariselli & al. 2020), Lig (Brunialti & al. 1999). C - Tosc, Sar.
Description: Thallus crustose, episubstratic, pale green, glaucous green or whitish grey, brighter green when wet, continuous, consisting of a soft layer of 100-300 µm thick, ecorticate, soredia-like to wart-like granules. Apothecia biatorine, round to irregular in outline, strongly constricted to substipitate, 1-2(-3.5) mm across, with a flesh-coloured to pale orange-pink, sometimes faintly white-pruinose, smooth to finally wrinkled, flat to convex disc, and a thin, smooth, sometimes irregularly lobulate, often paler, sometimes whitish-pruinose, finally often excluded proper margin. Proper exciple of intricately interwoven hyphae, extending below the hymenium; epithecium reddish brown, with many small crystals, K+ orange-red; hymenium colourless, 130-150 µm high, I+ blue; paraphyses simple or sparingly branched in upper part, slender, c. 1 μm thick at mid-level, the apical cells swollen, up to 5 μm wide; hypothecium colourless, the central part with colourless crystals not dissolving in K. Asci (6-)8-spored, narrowly cylindrical, I-, except for a thin I+ blue apical cap. Ascospores 1(-3)-septate, hyaline, fusiform-elongate, 12-28(-30) x 4-6(-7) μm. Pycnidia pale, immersed. Conidia bacilliform, 3.5-4.5 x 0.5-1 μm. Photobiont chlorococcoid (Coccomyxa), the cells ellipsoid, 5-8 x 3-4 µm, with a large parietal chloroplast, surrounded by a gelatinous layer. Spot tests: thallus K+ orange turning brownish orange, C-, KC+ orange, P+ orange, UV+ glaucous; apothecia K+ and P+ orange-red, UV-. Chemistry: thallus with thamnolic and perlatolic acid, apothecia with thamnolic acid only.
Note: a cool-temperate to boreal-montane, circumpolar species found on decaying wood and muribund bryophytes, usually in upland areas; common in the Alps, rarer on the high Mediterranean mountains.