Description: Thallus squamulose to subcrustose, brownish grey, often faintly to heavily grey-pruinose especially toward the centre, and darker toward the margin, thin. Squamules (0.5-)1-3 mm broad, finely divided-lobulate, appressed to the substratum, contiguous, very rarely somewhat overlapping, forming a subcrustose thallus developing on a dark prothallus; edge of squamules darker than the surface. Lower surface dark, attached by dark rhizohyphae which are (3.5-)4-4.5(-5) µm thick. Upper cortex thin, paraplectenchymatous, poorly delimited from the algal layer; medulla of spherical hyphae; lower cortex paraplectenchymatous, of polygonal cells in 2-3 layers. Perithecia numerous, laminal, globose, half immersed, not flattened, 0.2-0.3 mm across, without involucrellum. Paraphyses absent, substituted by periphyses; perithecial wall initially pale, then darkening throughout. Asci unitunicate, clavate, thin-walled, not or only slightly thickened at the apex, without ocular chamber, the wall I-. Ascospores 1-celled, hyaline, clavate, thin-walled, 14–24 × 6–9 µm, biseriately arranged in the asci. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P- UV-. Chemistry: without lichen substances.
Note: a boreal-montane to arctic-alpine, circumpolar species occurring also in more southern mountains on siliceous, base-rich soil with mica, or amongst terricolous bryophytes, usually near or above treeline. Some records from low elevations in Sicily appear as dubious to me.
Growth form: Squamulose
Substrata: soil, terricolous mosses, and plant debris