Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Mycelium: endothallic, in general invisible, only at the base of the ascomata are short portions of the pale brown vegetative hyphae Ascomata: with erumpent initials as black dots, subsequently gradually enlarging rough discs and persistent rough margins, 300-600 µm in diam. exciple: pseudoparenchymatic, composed of brown-walled cells measuring 5-10 µm in diam. hymenium: hyaline, 60-90 µm tall, neither the asci nor the hymenial gel reacting with I, with a brown epihymenium; paraphysoids: richly branched and anastomosing, 2-3 µm thick, with brown, slightly enlarged tips, partly connected with remnants of the obtecting ascomatal wall asci: broadly cylindrical, 50-65 x 12-15 µm, (4-6-)8-spored ascospores: brown, one-septate, 11-17(-19) x 6-8(-9) µm. Hosts: on the thallus of Diploschistes muscorum and Diploschistes sp., commensalistic or slightly parasitic; outside the Sonoran region also on Diploschistes scruposus World distribution: widely distributed in Europe, also known from Africa (Morocco), South America (Colombia), North America (U.S.A. and Mexico), and Australia Sonoran distribution: up to now known only from three inland localities in Arizona and Sonora within an altitudinal range from 700 to 2270 m. Notes: Karschia talcophila is a rather uncommon fungus, that apparently prefers temporarily warm and dry climates where a higher proportion of infested host thalli occur.