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, lichenized, or parasymbiotic Thallus: (of lichenized species) crustose, forming small patches on the host thallus, the patches discernable either by a color different from that of the host or by the groups of apothecia, without a prothallus surface: smooth to somewhat wrinkled, green or concolorous with the host thallus algal layer: horizontally continuous photobiont: coccoid green algae medulla: white, composed of intricately interwoven hyphae, I- lower cortex: absent Ascomata: apothecial, black, epruinose, laminal, normally dispersed on the host, semi-immersed to adpressed or breaking through the surface of the host thallus, urceolate to plane when young, later with plane to +convex discs, with distinct margin when young but later often indistinct exciple: carbonaceous, composed of dark brown, thick-walled, strongly conglutinated, radiating hyphae hymenium: hyaline or with greenish tinge, I+ bluish then red-brown (hemi-amyloid) hamathecium: present as paraphyses; paraphyses: richly branched and anastomosing, with pigmented tips forming a brown epihymenium hypothecium: pale to medium brown asci: lecanoralean, subventricose to clavate, with small tholus containing a I+ blue (euamyloid) cap-like layer (Catolechia-type), 8-spored ascospores: brown, 1septate, with isopolar cells, with thick layered wall, with more intensive pigmentation at the edge of the septum forming a so-called torus Conidiomata: not observed Secondary metabolites: pulvinic acid derivates or none Geography: bipolar, often at high elevations, with holarctic center of distribution Substrate: all species lichenicolous, two species on predominantly terricolous Baeomyces, one on saxicolous Lecidea. Notes: Epilichen represents a deviation from Catolechia to the lichenicolous life habit. This is quite evident when the type species of both genera, Epilichen scabrosus vs. Catolechia wahlenbergii are compared, but is more difficult to see in the other species, that have lost the ability to build the yellow-green lichen substances of the pulvinic acid type. The only species so far found in the Sonoran region is E. stellatus.