Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.

Life habit: lichenicolous initially on Staurothele areolata, eventually becoming independent Thallus: subsquamulose, 0.2-0.7 mm thick, lacking a prothallus areoles/squamules: finely crenulate-lobulate, densely aggregated and fitting together like pieces of a jigsaw puzzle or with margins slightly overlapping, 0.6-1.5 mm wide, margin brown surface: dark brown, smooth, slightly glossy anatomy: upper cortex: well delimited, 20-25 µm thick, composed of cells 3-6 µm in diam., uppermost cell layer with brown pigment caps, sometimes overlain by a very thin epinecral layer; algal layer: densely packed, 100-300 µm thick, with algal cells 4-10 µm in diam., mycobiont portion paraplectenchymatous, with wavy delimitation against medulla; alga-free medulla: subparaplectenchymatous, with cells 5-10 µm in diam.; lower cortex: present in the marginal part of areoles, 20-40 µm thick, paraplectenchymatous, pale brown, with granular inspersions centrally; below with hyaline, 3-4.5 µm thick rhizohyphae Perithecia: immersed, located entirely within the algal layer; exciple: (sub)globose, 0.18-0.27 mm wide, colorless; involucrellum: lacking; periphyses µm long, simple asci: clavate, 8-spored ascospores: hyaline, simple, broadly ellipsoid to subglobose, in the Californian sample 10-12 x 9-10 µm Pycnidia: immersed, small and inconspicuous conidia: bacilliform, 5-7 µm long Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on Staurothele areolata over calcareous rocks, montane World distribution: Europe (Alps, Pyrenees) and western North America Sonoran distribution: southern California (San Bernardino Mountains). Notes: The parasitic habit, brown, subsquamulose areoles, pale perithecia, and small, broadly ellipsoid to subglobose spores are diagnostic of Verrucaria zamenhofiana. The spores are variable in shape and size. Other North American samples have spores 10-16 x 6-8 µm, and there is also notable variation in spore size in European samples.