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; [th] upper surface: yellow(ish) white (ivory, off-white, cream-coloured); [th marginal and upper surface] specific structures: absent. Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (min) 0.38 (low) 0.45 (high) 0.53 (max) 0.64; 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) | black(ish) brown | red(dish) brown (if pale: orange brown); [ascm, if apoth] disc, mazaedium: epruinose | pruinose; [ascm, if apoth] disc, mazaedium pruina: scarce, sparse, fine | dense; [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: yellow(ish) white (ivory, off-white, cream-coloured); [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: hyaline, colourless; [ascm] paraphyses/-oids: present; [ascm] paraphyses/-oid cells width [µm]: (min) 2.0; [ascm] paraphyses/-oid apical cells width [µm]: (min) 2.0; [ascm] epihymenium, epithecium: blue(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon) | black(ish) green | brown(ish) green (olivaceous, olive green). 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]: (min) 7.0 (low) 8.5 (high) 10.0 (max) 12.0; [asp] width [µm]: (min) 3.0 (low) 4.2 (high) 5.4 (max) 6.0; [asp] septa: absent – spore lumen unilocular, monolocular; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent. Conidiomata: absent | present. Conidia: bacilliform, bacillary; [co] length [µm]: (low) 7.0 (high) 9.0. Secondary metabolites: present, isousnic acid. Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid. Secondary photobionts (eg in cephalodia): absent.