Global occurrence: Eurasia – Europe | Americas – North America (incl Mexico) | Arctic.  Substrate: rock – calcareous, calciferous, basic.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – episubstratal – unspecified; compartimentized – areolate, squamulate; [th] upper surface: grey(ish) | white(ish); [th marginal and upper surface] specific structures: absent.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (median) 0.7; [ascm, if apoth] disc, mazaedium: plane, flat, flattened, expanded | subconvex, slightly convex; [ascm, if apoth] disc, mazaedium: black(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon); [ascm] paraphyses/-oids: present; [ascm] epihymenium, epithecium: brown(ish) (if pale: fawn, tan; if mid: cinnamon).  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] length [µm]: (low) 12.0 (high) 16.0 (max) 18.0; [asp] width [µm]: (low) 4.0 (high) 5.0; [asp] septa: present, transversely septate; [asp] transversal septa: (median) 3.0; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.