Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: foliose to subfruticose to caespitose, 5-20 cm across, lobate lobes: linear, 1-3 (-5) mm wide, separate, subdichotomously branched, loosely imbricate; apices: subtruncate, eciliate upper surface: light gray to gray, smooth, plane to rugulose, shiny or dull, maculate or not, usually epruinose; soredia and isidia absent medulla: white, loosely packed lower surface: tan to black, sometimes mottled white, naked, channeled, erhizinate, attached by basal holdfasts Apothecia: usually present, laminal on thallus, orbicular, cup-shaped, subpedicellate or pedicellate, 2-10 mm in diam.; margin: prominent, with a thalloid rim; disc: dark brown asci: lecanoral, c. 8-spored ascospores: simple, ellipsoid, 7-10 x 4-6 µm; walls: thin, hyaline, not amyloid Pycnidia: laminal or marginal, immersed or emergent and sessile conidia: not seen Spot tests: upper cortex K+ yellow, C-, KC-, P+ yellow; medulla K-, C+ red, KC+ red, P- Secondary metabolites: upper cortex with atranorin and chloroatranorin; medulla with lecanoric acid (major). Substrate and ecology: usually on confers (especially Pseudotsuga and Abies) in mixed conifer forests World distribution: neotropics from Central America through Mexico to southwestern U.S.A. Sonoran distribution: eastern and especially SE Arizona south through the Sierra Madre Occidental of Chihuahua, Sonora and Sinaloa. Notes: Pseudevernia intensa is one the most common montane lichens on confers from eastern Arizona southwards and exhibits considerable morphological plasticity from narrow to wide lobed individuals and from clearly foliose to robustly subfruticose.