Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.
Thallus: areolate, with thin to rather broad fissures, moderately thick (0.2-0.3 mm), without a black basal layer, without an apparent prothallus areoles: subangular in outline, not sharp-edged, plane, 0.4-0.7 mm wide surface: greenish brown to brown, smooth, dull or slightly glossy anatomy: upper cortex: hardly developed, composed of 1-3 layers of 4-6 µm in diam. cells, with a brown pigmented uppermost cell layer overlain by a thin amorphous epinecral layer; algal layer: paraplectenchymatous, with algal cells 7-12 µm in diam., occupying the upper half of thallus; alga-free medulla: subparaplectenchymatous, colorless or patchily brown especially around bases of perithecia, with incorporated substrate particles Perithecia: immersed in thallus with tips more or less protruding, 1-2 per areole; exciple: subglobose, 0.25-0.30 mm wide, black, 15-20 µm thick; involucrellum: appressed to the exciple, extending down to exciple-base level, laterally c. 50 µm thick, broadening or not to 70-80 µm at base; periphyses 20-30 µm long, c. 3 µm thick asci: clavate, 65-75 x 20-25 µm, 8-spored ascospores: hyaline, simple, ellipsoid, 20-26 x 8-11 µm Pycnidia: unknown Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: epilithic, usually on calcareous rock; the Sonoran specimens are exceptional in that they are silicoloous; montane World distribution: Europe and North America Sonoran distribution: Arizona and southern California. Notes: Among the brown, thickly epilithic species, Verrucaria endocarpoides is characterized by immersed perithecia and stout periphyses.