Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Thallus: foliose, medium to large, 5-15 cm in diam., adnate lobes: +flattened and elongate (1-2 cm wide and up to 5 cm long), imbricate or separate; tips: rounded to subtruncate, often ascending and undulate upper surface: gray or blue-gray to brown when dry, blackish green when wet, smooth, shiny, rarely pruinose marginally, without isidia, schizidiate marginally medulla: white, with thick, +loosely interwoven hyphae photobiont: Nostoc lower surface: white, abruptly darkening, veinless, with small whitish spots, rhizinate rhizines: fasciculate, blunt, c. 3 mm long Apothecia: not seen in Sonoran material, elsewhere +round, on short lobes, up to 9 mm in diam.; margin: smooth to crenulate disc: flat, dark brown, smooth ascospores: colorless to pale brown, acicular, 3(-5)-septate, 27-40 x 4-6 µm Pycnidia: not seen in Sonoran material Spot tests: all negative Secondary metabolites: tenuiorin, methyl gyrophate, gyrophoric acid, hopane-6α,22-diol and unidentified terpenoids. Substrate and ecology: among mosses over soil World distribution: temperate and boreal regions of North America, Europe and Asia Sonoran distribution: Arizona (2100-3140 m) and Baja California. Notes: Thick, glossy and schizidiate thalli and a veinless lower surface are the main characters of P. elisabethae and distinguish it from its closest ally P. horizontalis.