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 | squamulose (squamulous) | placodioid-crustose, placodioid-foliose; compartimentized – areolate, squamulate; [th] upper surface: grey(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon) | brown(ish) grey | brown(ish) green (olivaceous, olive green); [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) width [mm]: (low) 0.3 (high) 0.5; [th] morphol substructures (eg areoles, lobes, branches) upper surface: smooth, plane | subsquamulose | squamulose; [th] lower surface: blue(ish) green (turquoise); [th lower surface] specific structures: absent.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma: subsessile, subimmersed, adnate, semi-immersed, emergent | sessile, superficial; [ascm, if apoth] disc, mazaedium: concave; [ascm, if apoth] disc, mazaedium: black(ish) [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: grey(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon) | brown(ish) grey | brown(ish) green (olivaceous, olive green) [ascm, if apoth] margin excipular photobionts: absent; [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | red(dish) brown (if pale: orange brown); [ascm] paraphyses/-oids: present.  Asci: lecanoralean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): present; [asc] tholus amyloidity pattern: with amyloid tube, ring (= Collema-, Micarea-, Porpidia-, Psora-types etc).  Ascospores: (median) 8.0; [asp] shape: ellipsoidal; [asp] length [µm]: (low) 13.0 (high) 20.0; [asp] width [µm]: (low) 7.0 (high) 8.0; [asp] septa: present, transversely septate; [asp] transversal septa: (low) 2.0 (high) 3.0; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent.  Conidiomata: absent | present.  Conidia: bacilliform, bacillary.  Secondary metabolites: absent.  Primary photobiont: present, cyanobacterial.  Secondary photobionts (eg in cephalodia): absent.