Bih. K. Svenska Vetensk.-Akad. Handl., 3, 18: 82, 96, 1892. Basionym: Lecidea melaena Nyl. - Bot. Not.: 182, 1853.
Synonyms: Bacidia melaena (Nyl.) Zahlbr.; Biatora stizenbergeri Hepp; Bilimbia melaena (Nyl.) Arnold; Catillaria constristans sensu H. Magn.; Lecidea ilyophora Stirt.
Distribution: N - Ven (Nascimbene 2008c), TAA (Thor & Nascimbene 2007, Nascimbene & al. 2007b, 2008c, 2014, Nascimbene 2008b, 2013, 2014, Nimis & al. 2015), Lomb, Piem, Emil (Fariselli & al. 2020). C - Tosc (Tretiach & al. 2008). S - Pugl.
Description: Thallus crustose, thinly episubstratic, continuous, granulose or areolate, yellowish brown, pale green or dark greenish grey, rarely almost black in sun-forms. Apothecia micareoid, black, 0.1-0.5 mm across, with a strongly convex, sometimes tuberculate, globulose disc and a thin, soon excluded proper margin. Epithecium olive-green or blue-green, K+ intensifying green; hymenium blue-green or purplish in lower part, I+ blue; paraphyses numerous, coherent, branched and anastomosing, 0.5-1(-2) µm thick; hypothecium purple-brown, K+ green or K+ intensifying purple, N+ purple. Asci 8-spored, cylindrical-clavate, the I+ blue tholus with a wide, I+ dark blue tube structure that expands towards the top, without a pale axial body. Ascospores (1-)3(-5)-septate, hyaline, ovoid or ovoid-oblong, with rounded ends, 12-21 x 4-6 µm. Pycnidia rare, black of two types: a) 100-140 µm across, sessile, the wall purple brown to olive, K+ green, producing 0-7-septate, curved or hook-shaped macroconidia measuring 18-33 x 1-1.5 µm, b) 40-60 µm across, semi-immersed to sessile, the wall green, K-, producing fusiform-cylindrical, straight microconidia measuring 4.5-7 x 0.5-1 µm. Photobiont micareoid, the cells 4-7 μm wide. Spot tests: thallus K-, C- or C+ red, P-; apothecial sections C-. Chemistry: thallus with gyrophoric acid in variable amounts.
Note: a cool-temperate to circumboreal-montane species found on decomposed lignum of old stumps, but also on plant debris, siliceous rocks and soil rich in humus, mostly in humid upland areas; widespread in the Alps and the Northern Apennines.