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, often inconspicuous and poorly developed upper surface: various shades of white, gray, green, or orange to pink; occasionally with isidia or schizidia photobiont: primary one a trentepohlioid alga, secondary photobiont absent Ascomata: perithecioid but in some species expanding an appearing apothecioid, immersed to subimmersed in the thallus involucrellum: absent; true exciple: hyaline to brownish black, 30-60 µm wide, upper and inner parts paraplectenchymatous hamathecium: composed of short-celled, stiff periphyses (up to 45 x 2 µm); hymenium: hyaline or pale brown, I+ blue-green, rapidly changing to red-brown; paraphyses: slender, c. 200 x 1.5-2 µm, flexuose, not branched and without apical thickening asci: narrowly cylindrical, 100-180 x 12-18 µm, tapering apically, unitunicate, thin-walled, without apical thickening or apparatus, 8-spored ascospores: broadly ellipsoid to ovoid, hyaline, muriform with eusepta, 2-20 x 13-120 µm Conidiomata: pycnidial, ± sessile conidia: bacilliform, macro- and micro- may be present Secondary metabolites: none detected Geography: Mediterranean regions of Europe and across southern USA and the Caribbean Substrate: species occurring on either bark or rocks, especially calcareous ones. Notes: Among the perithecioid genera occurring in the Sonoran region, Topelia is most similar to Thelenella and Thelopsis. Thelenella differs by lacking periphyses, having an I- hymenium and richly branched, anastomosing paraphyses and having thick-walled asci. In contrast, the ascocarps, hymenium and asci of Thelopsis are very similar to Topelia, but the exciple and spores are different. 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.