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) – endosubstratal, inconspicuous, immersed | crustose (crustaceous) – episubstratal – unspecified; continuous, diffuse, effuse; [th] upper surface: white(ish); [th marginal and upper surface] specific structures: absent.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (min) 0.2 (low) 0.3 (high) 0.5 (max) 0.7; ascoma: sessile, superficial; [ascm, if apoth] disc, mazaedium: subconvex, slightly convex | convex | distinctly convex | strongly convex, hemispherical, (sub-)globose; [ascm, if apoth] disc, mazaedium: black(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon) | brown(ish) black | red(dish) brown (if pale: orange brown); [ascm, if apoth] disc, mazaedium: epruinose; [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: brown(ish) (if pale: fawn, tan; if mid: cinnamon); [ascm, if apoth] margin excipular photobionts: absent | present; [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: hyaline, colourless; [ascm] paraphyses/-oids: present; [ascm] paraphyses/-oid apical cells width [µm]: (low) 3.0 (high) 4.0; [ascm] epihymenium, epithecium: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | red(dish) brown (pale: orange brown).  Asci: lecanoralean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): present; [asc] tholus amyloidity pattern: entirely amyloid (= Catillaria-, Teloschistes-types etc).  Ascospores: (median) 8.0; [asp] shape: ellipsoidal | [cur] – curved, unciform, falcate, sickle-shaped; [asp] length [µm]: (min) 8.0 (low) 9.0 (high) 12.0; [asp] width [µm]: (min) 2.5 (low) 3.0 (high) 4.0 (max) 5.0; [asp] septa: absent – spore lumen unilocular, monolocular | present; [asp] septa: transversely septate; [asp] transversal septa: (median) 1.0; [asp] pigmentation: hyaline, colourless | pale brown; [asp] perispore, epispore: not apparent.  Conidiomata: absent | present.  Conidia: [co] length [µm]: (low) 14.0 (high) 18.0.  Secondary metabolites: absent.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.