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 Thallus: crustose, superficial or immersed, thin, homiomerous, effuse; prothallus: absent upper surface: various shades of gray or orange-red, smooth photobiont: primary one a trentepohlioid alga, secondary photobiont absent Ascomata: perithecial, globose, partially immersed to sessile, ± tough, pale reddish brown to black, not friable involucrellum: absent true exciple: hyaline to brownish black, 30-60 µm wide, upper and inner parts paraplectenchymatous hamathecium: paraphyses thread-like, unbranched, persistent; hymenium: hyaline, I+ blue changing to red-brown asci: narrowly cylindrical, tapering apically, unitunicate, thin-walled, without apical thickening or apparatus, multispored ascospores: ellipsoid to shortly fusiform, hyaline, 1-3 septate to submuriform, 13-120 x 2-20 µm Conidiomata: pycnidial, very rare, pale conidia: thread-like, straight or slightly curved Secondary metabolites: none detected Geography: Mediterranean regions of Europe and southern North America Substrate: species occurring on either bark, calcareous or acidic rocks, or detritus. Notes: Among the perithecioid genera with trentepohlioid algae occurring in the Sonoran region, Thelopsis is most similar to Topelia. In Thelopsis and exciple is lacking and the spores are usually only transversely septate, rarely submuriform and always occur as more than 8 per ascus; whereas, in Topelia a well developed exciple is present and the spores are soon muriform and are 8 per ascus. The only other pyrenocarpous genus in the region with a large number of spores per ascus is Trimmatothele, but its spores are always simple and its photobiont is a chlorococcoid green alga.