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; thallus: cracked, fissured, fractured, rimose | compartimentized – areolate, squamulate; [th] upper surface: grey(ish) | white(ish) | brown(ish) white; [th marginal and upper surface] specific structures: absent. Ascomata: absent | present; ascoma: perithecial, perithecioid – hymenial; ascoma [mm]: (low) 0.32 (high) 0.78; ascoma: subsessile, subimmersed, adnate, semi-immersed, emergent; [ascm, if apoth] margin excipular photobionts: absent; [ascm] paraphyses/-oids: absent. Asci: fissitunicate – verrucarialean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): absent. Ascospores: (median) 8.0; [asp] shape: ellipsoidal; [asp] length [µm]: (min) 15.0 (low) 19.5(median) 22.3 (high) 25.0 (max) 30.0; [asp] width [µm]: (min) 7.5 (low) 9.0(median) 10.3 (high) 11.5 (max) 15.0; [asp] septa: absent – spore lumen unilocular, monolocular; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent. Secondary metabolites: absent. Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid. Secondary photobionts (eg in cephalodia): absent.