Description: Thallus inapparent, not lichenized, the hyphae developing inside old parts of thalli of Peltigera- and Solorina-species, the infected parts appearing as dark-brown, elevated, rough-surfaced, 0.5-2 mm wide (but sometimes confluent) patches which are often surrounded by a white ring of bleached host tissue. Apothecia arthonioid, developing in the cortex of the host, more or less round, adnate, 0.5-1.5(-2) mm across, with a reddish brown to purple-black, convex disc, without a proper margin. Proper exciple poorly developed, composed of rounded, thin-walled, c. 0.5 μm wide cells; epithecium orange- to red-brown, K+ dull brown; hymenium pale orange-brown, I+ red, K/I+ blue, K+ dull brown; paraphysoids branched and anastomosing, 1.5-3 µm thick, extending periclinally above the asci to form the epithecium; hypothecium pale brown. Asci 8-spored, broadly clavate to subglobose, semi-fissitunicate, with a large, non-amyloid apical dome, and a distinct ocular chamber, Arthonia-type. Ascospores 1-septate, the upper cell upper cell shorter, broader and more rounded than the lower cell, hyaline but often guttulate and appearing brownish, ellipsoid-elongate, 9-15 x 3-4.5 µm. Pycnidia clustered, red-brown. Conidia bacilliform, up to 5 µm long. Photobiont absent. Spot tests: K-, C-, KC-, P-. Chemistry: without lichen substances.
Note: a lichenicolous fungus growing on the thalli of Peltigera-species; never reported from Italy, but to be looked for, especially in the Alps.
Growth form: Lichenicolous fungus
Substrata: soil, terricolous mosses, and plant debris