Description: Thallus crustose, episubstratic, whitish to whitish grey or pale yellowish brown, extremely variable, very thin to very thick, with or without long spine-like outgrowths, continuous and membrane-like to areolate-verrucose, the areoles sometimes tending to become subfruticose, esorediate or sorediate; soredia farinose or granular, forming more or less discrete soralia on continuous thalli, or developing on the top of areoles, rarely at the base of spines, or areoles completely dissolving into soredia, and forming a sorediate crust. Apothecia frequent, lecanorine, up to 4 mm across, with a concave to flat, usually epruinose, often radially fissured, pale brown ro reddish brown disc, a usually smooth or sorediate thalline margin, and often a prominent excipular ring. Thalline exciple corticate, the cortex c. 50-75 μm wide; epithecium brownish, C+ red; hymenium colourless, c. 170-250(-300) μm high; hypothecium yellowish. Asci (4-)6-8(-12)-spored, with thick, amyloid walls, Pertusaria-type. Ascospores 1-celled, hyaline, variable in size and shape, from ellipsoid to pyriform, rarely subglobose, 20-55 x 10-35 μm. Photobiont chlorococcoid. Spot tests: thallus K-, C+ red, KC+ red, P-; medulla C-, KC-. Chemistry: gyrophoric (major) and lecanoric (trace to minor) acids, sometimes with traces of additional unidentified substances.
Note: an arctic-alpine, circumpolar species found on mosses, plant debris and soil in the Alps, where it reaches the nival belt. All Italian records need confirmation (see Nimis 1993: 455).
Growth form: Crustose
Substrata: soil, terricolous mosses, and plant debris