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

Thallus: foliose, irregularly spreading, deeply divided or incised and appearing polyphyllous, 2-5(-7) cm in diam., rather papery and thin when well-developed, flabby when moist, brittle when dry lobes: irregularly laciniate, rather ragged, not broadly rounded, 5-15(-25) mm wide, 1030(-60) mm long; margins: entire to shallowly notched or incised, slightly thickened below, isidiate, rarely with projecting cilia or tomentum upper surface: livid slate gray, dark glaucous gray to blue-black, suffused red-brown in parts when moist, pale glaucous gray to pale brown with distinctly blackened margins when dry, shallowly to deeply wrinkled or subfaveolate especially at or towards margins where concentric ridges are sometimes developed, dull to glossy, maculate, rarely phyllidiate, soredia absent, commonly isidiate isidia: minute, granular to very delicately coralloid, brown-black to black, shiny, clustered at margins and on thalline ridges, occasionally forming small, sooty areas, often widely scattered, sometimes noticeably stalked in groups on the upper surface, and becoming flattened-phyllidiate medulla: white, K- photobiont: cyanobacterial lower surface: pale cream to pale buff and often glabrous in a marginal zone, darkening towards center, tomentose centrally and sometimes also from margins; tomentum: white or pale gray to red-brown, short and velvety near margins, longer and more shaggy centrally cyphellae: scattered, moderately common, fairly small but larger centrally, 0.1-0.5 mm in diam., round to subirregular, with rather flat margins, smoothly rounded, concolorous with lower surface, often immersed in tomentum, with a white basal membrane Apothecia: absent Pycnidia: occasional to rare, scattered at or near lobe margins, visible as pale white or fawn-colored to dark olive-brown swellings, 0.5-1 mm in diam., with a central, red-brown, punctiform ostiole conidia: not seen Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: in pine-oak, pine-fir, and Pseudotsuga forest on bark (Quercus), among mosses and detritus and on damp, acid rocks and cliff faces in shaded, humid habitats, 1700-3050 m World distribution: strongly oceanic in western Europe, Greenland, Madeira, the Canary Islands, the Mediterranean region, Ukraine, western North and South America (SW U.S.A.and Mexico to Peru) Sonoran distribution: Arizona, southern California, and Chihuahua. Notes: Material provisionally identified as S. sylvatica includes a collection of a robust, coriaceous, large-lobed specimen having densely clustered, terete, coralloid isidia that are larger than normal, and may in fact be referable elsewhere.