Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: verrucose, well developed or sometimes almost immersed surface: dark gray, cortex: 11-12 µm thick, consisting of intricately interwoven, gelatinized hyphae Apothecia: immersed in verrucae with a distinctly incised base, epruinose, with an ochraceous pigment in basal part of the verrucae and near the exciple exciple: uniformly thin, rim-like, laterally 25-34 µm wide, scarcely thickened at base, consisting of intricately interwoven, brown, sclerotized hyphae hypothecium: very thin, poorly pigmented mazaedium: 0.2-0.4 mm wide asci: obovate to pyriform, cylindrical or irregular, bursting at very early stages, (17)21-27 x 5-7(-9) µm, with 2-3-seriate spores ascospores: brown, 1-septate and constricted in the middle, +broadly ellipsoid, 20-23 x 10-14 µm; surface: smooth, not striated and without cracks Spot tests: thallus K+ reddish brown, C-, KC-, P- Secondary metabolites: none detected or unknowns. Substrate and ecology: on dry, weathered wood, e.g., of Quercus, often on wooden fences in lowland areas World distribution: Europe, North America, and Australasia Sonoran distribution: southern California at 1370 m. Notes: Cyphelium trachylioides is similar to C. tigillare but lacks the yellowish green color due to the absence of rhizocarpic acid, and has an ochraceous, K+ deep red (reaction reversible in acids) pigment in the basal part of the verrucae, often concentrated close to the exciple, and also abundant in the thalline parts immersed in the substrate; C. trachylioides also differs in having constantly small and at the base incised verrucae with small apothecia, different spore form (generally broader and partly somewhat longer), and has a different distribution (Temperate Zone, vs. Upper Oroboreal and Northern Boreal Zone for acid-deficient specimens of C. tigillare).