Global occurrence: Eurasia – Europe | Arctic.  Substrate: rock – calcareous, calciferous, basic | rock, stones, pebbles – unspecified.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – endosubstratal, inconspicuous, immersed | crustose (crustaceous) – episubstratal – unspecified; continuous, diffuse, effuse | cracked, fissured, fractured, rimose | compartimentized – areolate, squamulate; [th] upper surface: white(ish) | grey(ish) white; [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) upper surface: smooth, plane | granulose, granular.  Ascomata: absent | present; ascoma: perithecial, perithecioid – hymenial; ascoma [mm]: (low) 0.2 (high) 0.4 (max) 0.5; ascoma: immersed, innate; [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: black(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon); [ascm, if apoth] margin excipular photobionts: absent; [ascm] paraphyses/-oids: absent.  Asci: fissitunicate – verrucarialean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): absent.  Ascospores: (median) 8.0; [asp] shape: ellipsoidal; [asp] length [µm]: (min) 20.0 (low) 36.5 (high) 48.0 (max) 53.5; [asp] width [µm]: m(min) 12.0 (low) 18.0 (high) 24.0 (max) 28.0; [asp] septa: present, transversely septate | muriformly septate – muriform, submuriform; [asp] pigmentation: hyaline, colourless | pale brown; [asp] perispore, epispore: not apparent.  Conidiomata: absent | present.  Conidia: bacilliform, bacillary.  Secondary metabolites: absent.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.