Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.

Thallus: indistinct, thin upper surface: membrane-like, evanescent, pale gray, greenish when wet prothallus: absent Perithecia: 0.1-0.3 mm diam., sessile to slightly immersed, black, rounded to pyriform, discrete, very rarely 2-4 contiguous; exciple: dull greenish above (K+ violaceous), paler below, 15-20 µm thick asci: cylindrical, 8-spored ascospores: colorless, submuriform, elongate or narrowly ellipsoid, 22-33 x 7-10 µm Pycnidia: not seen Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: encrusting dead mosses and dead lichen thalli, rarely on acid soil and plant detritus in upper montane to alpine habitats World distribution: mountains of central Europe, northern Europe, North America Sonoran distribution: only known from one locality in Apache National Forest in Arizona at 3000 m. Notes: This species is characterized by an indistinct thallus, small sessile black perithecia with a dull greenish exciple and elongate submuriform ascospores. Another species known from North America is Protothelenella sphinctrinoides (Nyl.) H. Mayrhofer & Poelt, which is distinguished by larger partly immersed perithecia and larger muriform ascospores.