Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Life habit: lichenized or non-lichenized, saprophytic;. Thallus: crustose, usually immersed but sometimes superficial, sometimes areolate, occasionally with pseudocyphellae or pockets of crystals, often surrounded by a hypothallus photobiont: primary one a trentepohlioid alga or absent, secondary photobiont absent Ascomata: perithecial, black, often aggregated in pseudostromata involucrellum: dark brown to black, clypeate, composed of fungal hyphae interspersed with bark cells and often K+ reddish or violet crystals ascomatal wall: black, usually continuous below the hamathecium, often partly immersed in the thallus; true exciple: brown to pale brown, entire or not developed below the perithecial cavity, colorless or orange crystals often dense at the wall lining the locule hamathecium: initially branched, anastomosed, sparsely septate paraphysoids; then replaced by unbranched paraphyses, not anastomosing, non-amyloid, hemiamyloid or amyloid; periphyses delveloped along the ostiolar canal asci: bitunicate, clavate to cylindrical, long-stalked, with tholus, thickened at the apex with an internal apical beak, non-amyloid ascospores: brown, ellipsoid to fusiform, transversely 2-30-septate, or muriform, with distosepta and often additional eusepta, 9-200 x 4-55 µm; walls: not ornamented Conidiomata: pycnidial, black conidia: filiform, simple, hyaline Secondary metabolites: lichexanthone, or anthraquinones, or absent Geography: cosmopolitan, but most diverse in the tropics Substrate: mostly on bark, but also on non-calcareous rock. Notes: the genus is in its current delimitation characterized by the combination of clypeate ascomata and brown, distoseptate ascospores and simple paraphyses.