Global occurrence: Eurasia – Europe | Americas – North America (incl Mexico) | Arctic.  Substrate: wood – dead, living | bark, cork, plant surface – trunks, branches, twigs.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – episubstratal – unspecified; continuous, diffuse, effuse | compartimentized – areolate, squamulate; [th] upper surface: white(ish) | yellow(ish) grey; [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) upper surface: verrucose, warted.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (low) 0.5 (high) 1.0; [ascm, if apoth] disc, mazaedium: concave | subconvex, slightly convex; [ascm, if apoth] disc, mazaedium: yellow(ish) (if dull: buff); [ascm] paraphyses/-oids: present.  Asci: lecanoralean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): present; [asc] tholus amyloidity pattern: amyloid with acuate axial body towards the apex (= Bacidia-, Buellia-, Ramalina-types etc).  Ascospores: (median) 8.0; [asp] septa: present, transversely septate; [asp] transversal septa: (median) 1.0; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent.  Conidiomata: absent | present.  Secondary metabolites: present, usnic acid.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.