Description: Thallus crustose, continuous, smooth or faintly rimose-cracked, grey to dark olive-brown, often delimited from conspecific thalli by a dark prothallus, forming extended mosaics. Apothecia deeply immersed in the thallus, at first punctiform, then elongate and lirelliform, 0.1-0.3 x 0.05-0.01 mm, brown-black, without a distinct margin. Proper exciple very thin, brownish, not extending below the hymenium; epithecium brown; hymenium colourless I+ wine-red; paraphyses 0.8-1 μm thick, branched in upper part and anastomosing, conglutinated, not swollen at tips; hypothecium colourless. Asci 8-spored, cylindrical to cylindrical-clavate, fissitunicate, with a short ocular chamber surrounded by a thin, K/I+ dark blue ring. Ascospores (1-)3(-6)-septate, hyaline, fusiform, straight or slightly curved, 25-38 x 4-6 μm, rather thick-walled, without a perispore. Pycnidia frequent, immersed, the wall colourless or pale brown in upper part. Conidia 1-celled, hyaline, cylindrical to bacilliform, 4-6 μm long. Photobiont trentepohlioid. Spot tests: thallus K-, C- KC-, P-, UV-. Chemistry: thallus with confluentic acid.
Note: a mild-temperate to humid subtropical epiphytic lichen found on smooth bark in riparian, open, humid-warm woodlands below the montane belt; mainly Tyrrhenian, probably extinct in northern Italy.
Growth form: Crustose
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)