Global occurrence: Eurasia – Europe | Americas – North America (incl Mexico) | Arctic.  Substrate: rock – siliceous, siliciferous, acidic.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – episubstratal – unspecified; cracked, fissured, fractured, rimose | compartimentized – areolate, squamulate; [th] upper surface: grey(ish) | red(dish) grey; [th marginal and upper surface] specific structures: absent | present; [th margin] cilia, cilioid structures: absent; [th upper surface] isidia, isidioid structures: absent | present; [th upper surface] soredia, soralia, soralioid structures: absent; [th] morphol substructures (eg areoles, lobes, branches) width [mm]: (low) 0.3 (high) 0.7 (max) 1.0; [th] medulla amyloidity: absent.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (low) 0.6 (high) 0.8 (max) 1.2; ascoma: sessile, superficial; [ascm, if apoth] disc, mazaedium: plane, flat, flattened, expanded | subconvex, slightly convex; [ascm, if apoth] disc, mazaedium: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | red(dish) brown (if pale: orange brown); [ascm, if apoth] margin excipular photobionts: present; [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | hyaline, colourless; [ascm] paraphyses/-oids: present; [ascm] paraphyses/-oid cells width [µm]: (low) 1.5 (high) 2.0; [ascm] paraphyses/-oid apical cells width [µm]: (low) 2.5 (high) 5.0; [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: with amyloid tube, ring (= Collema-, Micarea-, Porpidia-, Psora-types etc).  Ascospores: (median) 8.0; [asp] shape: ellipsoidal; [asp] length [µm]: (low) 17.0 (high) 30.0; [asp] width [µm]: (low) 9.0 (high) 15.0; [asp] septa: absent – spore lumen unilocular, monolocular; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: thin, thinly halonate | thick, distincly halonate.  Conidiomata: absent | present; [co] length [µm]: (low) 3.5 (high) 5.0.  Secondary metabolites: present, 5-O-acetyl-4-O-methylhiascic acid.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.