Description: Thallus crustose, continuous, rimose-areolate, or warted-areolate, white to grey or brown-grey, sometimes poorly evident. Apothecia lecideine, black to rarely dark brown-black, 0.2-0.5 mm across, with a persistently flat to slightly convex, epruinose disc, and a distinct, persistent or rarely finally excluded, concolorous proper margin. Proper exciple 26-45 μm wide laterally, without crystals, the outer rim black-brown or dark red-brown, sometimes paler downwards, without a layer of enlarged cells, the medullary part colourless or very pale brown; epithecium purple-brown to dark brown, scarcely differentiated from hymenium, K+ intensifying purple; hyrnenium (35-)45-50(-70) μm high, colourless except for occasional vertical brown streaks; paraphyses mostly simple, 1.-1.5(-2) μm thick at mid-level, the apical cells clavate, 3.5-4(-6) μm wide; hypothecium colourless or very pale brown; all pigmented parts of apothecia K+ purplish and N+ orange-red. 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-septate, hyaline, bacillifom or clavate, usually strongly curved or sigmoid, rarely almost straight, coiled in the asci, (14-)16-35(-40) x 2-3(-4) μm. Pycnidia half-immersed, black, the wall K+ brown-purple. Conidia 1-celled, hyaline, of two types: a) ellipsoid or short-bacilliform, 2.8-3.6 x 1.2-1.6 μm, b) bacilliform, straight or slightly curved, 6-9 x 0.5-0.8 μm. Photobiont chlorococcoid, the cells 5-14 μm in diam. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: thallus without lichen substances; apothecia and pycnidial walls with the Laurocerasi-brown pigment.
Note: on the bark of broad-leaved trees in rather humid situations, more rarely on lignum. For nomenclatural problems see Ekman (1996). The species was included as “Regionally Extinct” in the Italian red list of epiphytic lichens (Nascimbene & al. 2013c).