Global occurrence: Eurasia – Europe | Americas – North America (incl Mexico) | Arctic.  Substrate: rock – siliceous, siliciferous, acidic | rock, stones, pebbles – unspecified.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – episubstratal – unspecified, compartimentized – areolate, squamulate; [th] upper surface: grey(ish); [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) upper surface: smooth, plane.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (low) 0.2 (high) 0.5 (max) 0.7; ascoma: immersed, innate | sessile, superficial; [ascm, if apoth] disc, mazaedium: plane, flat, flattened, expanded; [ascm, if apoth] disc, mazaedium: black(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon); [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: black(ish) | grey(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon); [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: grey(ish); [ascm] paraphyses/-oids: present; [ascm] paraphyses/-oid cells width [µm]: (low) 2.0 (high) 3.0; [ascm] paraphyses/-oid apical cells width [µm]: (low) 3.5 (high) 4.0; [ascm] epihymenium, epithecium: yellow(ish) (if dull: buff) | 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 widening axial body towards the apex (= Lecanora-, Parmelia-, Rinodina-types etc).  Ascospores: (median) 8.0; [asp] shape: ellipsoidal; [asp] length [µm]: (low) 9.0 (high) 15.0; [asp] width [µm]: (low) 4.0 (high) 6.0; [asp] septa: absent – spore lumen unilocular, monolocular; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent.  Conidiomata: absent | present.  Conidia: filiform, vermiform | [cur] – sigmoidal | [cur] – curved, unciform, falcate, sickle-shaped; [co] length [µm]: (low) 18.0 (high) 25.0.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.