Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.
Thallus: indistinct or continuous or patchily, finely rimose, bordered by a dark, sometimes fimbriate prothallus surface: whitish or brownish gray, gray-green to brown, smooth to slightly rough, sometimes minutely dotted anatomy: undifferentiated, thallus filled by algal cells 5-9 µm in diam., containing substrate particles Perithecia: prominent; exciple: colorless to brown, 0.2-0.3 mm wide; involucrellum: hemispherical, extending down to base, c. 40 µm thick; periphyses c. 20 µm long, simple asci: broadly clavate, 60-70 x 20-25 µm, 8-spored ascospores: hyaline, simple, ellipsoid, 15-20(-22) x 6-8 µm Pycnidia: unknown Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: thinly epilithic to partially endolithic, on or in sandstone and siliceous rocks World distribution: as mostly not treated as separate from Verrucaria dolosa, the distribution cannot be accurately outlined Sonoran distribution: several collections from southern California (Channel Islands and Santa Monica Mountains) and Baja California. Notes: Both the spores and perithecia of Verrucaria floerkeana are markedly larger than in V. dolosa, otherwise the species are very similar. The involucrella are of about the same thickness in both species, but seem to be comparatively thinner in Verrucaria floerkeana due to the larger perithecia of the latter. Verrucaria olivacella has equally sized spores but smaller perithecia than V. floerkeana. Verrucaria amylacea has a thicker involucrellum.