Bih. K. Svenska Vetensk. Akad. Handl., 3, 18, 3: 96, 1892
Description: Thallus crustose, endosubstratic or episubstratic and then consisting of whitish, convex, 0.1-0.4 mm wide areoles, Apothecia micareoid, dull black, from the beginning convex-hemispherical to subglobose, 0.2-0.3 mm across, often confluent into tuberculate, up to 0.5 mm wide aggregates, without a distinct proper margin. Proper exciple poorly developed, usually not evident; epithecium scarcely differentiated from the hymenium; hymenium aeruginose-green in upper and lower parts, colourless with vertical green streaks in middle part, K-, N+ red, 28-42 µm high; paraphyses of 2 types: a) evenly distrìbuted, flexuose, branched, 0.7-1 µm thick, the apical cells sometimes pigmented and up to 2.5 µm wide; b) scattered or gathered in small fascicles, stout, c. 2 µm thick, coated by a greenish pigment; hypothecium dark brown, K-, N+ red, 120-200 µm high. Asci 8-spored, clavate, the I+ blue tholus with a wide, intensely I+ dark blue tube structure that expands towards the top, without a pale axial body. Ascospores 1-celled, hyaline, ovoid or tear-shaped, 5-9 x 2.5-4 µm. Pycnidia numerous, black, sessile, 40-60 µm across, usually stalked, the stalks simple or rarely branched, bearing 1-4 pycnidia, the pycnidial wall dark olive green, the stalk tissue reddish brown, K-. Conidia short-cylindrical, 2.3-3.6 x 1-3 µm. Photobiont micareoid, the cells 4-7 μm wide. Spot tests: thallus K-, C-, KC-, P-. Chemistry: thallus probably without lichen substances.
Note: on lignum and conifer bark in boreal to temperate-montane forests; a very rare species, known also from the Eastern Alps (Austria); to be looked for in the Italian Alps.