Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Life habit: lichenicolous, non-lichenized Ascomata: apothecioid pseudothecia, black, erumpent, +round, with prominent rough margin, with a disc that becomes exposed by crumbling of the obtecting parts of the ascomatal wall exciple: pseudoparenchymatic, composed of cells with dark brown walls hymenium: hyaline, distinct, with I- (or giving a faintly blue reaction with I after pretreatment with K) hymenial gel; hamathecium: present as paraphysoids; paraphysoids: branching and with anastomoses, showing even in mature ascomata some connections with remnants of the ascomatal wall overlaying the epihymenium hypothecium: pale to dark brown asci: broadly cylindrical to slightly ventricose, fissitunicate, with an apically enlarged endoascal wall layer ascospores: brown, one-septate, with constantly narrower lower cell, with solid wall but without germinating pores Conidiomata: not observed. Geography: widely distributed, most records from the Northern Hemisphere, but uncommon Substrate: type species on thallus of Diploschistes spp., the other species restricted to other genera, i.e. Porpidia and Allantoparmelia. Notes: For a long time the genus Karschia was used for all lichenicolous discomycetes with brown, one-septate ascospores. Subsequently, thorough investigations of the hymenial characters of selected taxa have shown the high heterogeneity of that collective genus (Hafellner and Poelt 1976). Hafellner (1979) demonstrated that the majority of taxa previously placed Karschia belonged to other genera leaving Karschia s. str. as a relatively small genus. Only the type species is known from the Sonoran region. For further taxa previously placed in Karschia and occurring in the Sonoran region see under Buelliella and Dactylospora.