Description: Thallus crustose, mostly endosubstratic and inconspicuous, pale brown or olive-grey, doubtfully lichenized. Apothecia arthonioid, more or less immersed, rounded to slightly and irregularly lobed, 0.1-0.3 mm wide, with a black, epruinose, convex disc, without a proper margin. Epithecium brown-black, K-; hymenium colourless 45-55 μm high, I+ red; paraphysoids 0.5-1.5 μm thick at base; hypothecium brown, 25-35 μm high, K+ green. Asci 8-spored, subglobose, semi-fissitunicate, with a large apical dome and a distinct ocular chamber, Arthonia-type. Ascospores 1-septate and slightly constricted at septum, with slightly unequal cells, hyaline, ellipsoid, 12-15 x 4-5 μm. Photobiont absent or trentepohlioid. Spot tests: K-, C-, KC-, P-. Chemistry: thallus without lichen substances.
Note: a rare, perhaps non-lichenised corticolous species known from a few stations in the submediterranean and montane belts of the Alps and in central Europe.