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

Thallus: foliose, very loosely adnate, usually free growing and +tubular, leathery, 3-10 cm in diam. or fragmenting into separate lobes, dichotomously lobate; lobes: sublinear, elongate, extremely convex except the lobe apices, separate to overlapping,, 1.5-5 mm wide, not lobulate; apices: subrotund, sometimes revolute, smooth to crenate, eciliate; upper surface: yellow-green, smooth initially but becoming rugulose and cracked with age, shiny, epruinose and emaculate, without isidia, soralia or pustulae; medulla: white, with continuous algal layer; lower surface: pale to dark brown, strongly convolute but not completely inrolled, often with raised rim towards apices, moderately to densely rhizinate; rhizines: pale brown, simple to furcate, 0.3-1 mm long; Apothecia: very rare, substipitate, 2-4 mm wide, laminal on thallus; disc: cinnamon-brown to dark brown, epruinose; margin isidiate; asci: clavate, 8-spored; ascospores: hyaline, simple, ellipsoid, 11-13 x 5-6 μm; Pycnidia: rare, immersed; conidia: bifusiform, 6-7 x 0.5 μm; Spot tests: upper cortex K-, C-, KC-, P-; medulla K+ yellow to dark red, C-, KC-, P+ orange; Secondary metabolites: upper cortex with usnic acid (major); medulla with salazinic acid (major) consalazinic acid (minor), and usually norstictic and protocetraric acids (both trace).

Substrate and ecology: on soil, often in open, arid habitats; World distribution: intermountain areas of western North America; Sonoran distribution: occasional at intermediate elevations in pinyon-juniper communities in northern Arizona and Baja California.

  Notes: The considerable confusion over names for the common soil species is well discussed by Hale (1990, p. 81), who separates X. camtschadalis (Ach.) Hale as being uniformly white maculate and the predominately South American X. vagans (Nyl.) Hale as having stictic acid instead of salazinic acid. Another name often used is the Southern Hemispheric X. molliuscula (Ach.) Hale, another stictic acid containing species that has a canaliculated lower surface and often has well developed lobules. The even more strongly tubular Australian species, X. convoluta (Krempelh.) Hale also has salazinic acid.