Global occurrence: Eurasia – Europe | Americas – North America (incl Mexico).  Substrate: soil, clay, humus, turf, detritus, dead leaves | rock – calcareous, calciferous, basic | rock, stones, pebbles – unspecified.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – endosubstratal, inconspicuous, immersed; [th upper surface]: pruinose; [th upper surface] pruina: dense; [th marginal and upper surface] specific structures: absent.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial | perithecial, perithecioid – hymenial; ascoma [mm]: (low) 0.16 (high) 0.2 (max) 0.37; [ascm, if apoth] disc, mazaedium: yellow(ish) (if dull: buff); [ascm, if apoth] disc, mazaedium: pruinose; [ascm, if apoth] disc, mazaedium pruina: scarce, sparse, fine | dense; [ascm] paraphyses/-oids: present.  Asci: unitunicate; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): present; [asc] tholus amyloidity pattern: with amyloid tube, ring (= Collema-, Micarea-, Porpidia-, Psora-types etc) | with amyloid cap (= Icmadophila-, Lecidea-, Pertusaria-types etc).  Ascospores: (low) 50.0 (high) 300.0; [asp] shape: ellipsoidal | oblong, oblong-obtuse; [asp] length [µm]: (low) 6.0 (high) 8.5 (max) 11.0; [asp] width [µm]: (low) 4.0 (high) 4.5 (max) 5.0; [asp] septa: absent – spore lumen unilocular, monolocular; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent.  Secondary metabolites: present, pulvinic acid.  Primary photobiont: absent | present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.