Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: foliose, small to medium sized, moderately to loosely attached, lobate lobes: linear and discrete to somewhat more rounded, irregular or flabellate upper surface: gray to dark brown or reddish brown, with a white to grayish pruina developed on at least part of the thallus (lobe ends) and sometimes continuous; one species with coarse cortical hairs near lobe ends upper cortex: paraplectenchymatous or scleroplectenchymatous medulla: white to pale or medium yellow lower cortex: prosoplectenchymatous, often irregularly so (due to the hyphae being curved and zig-zagging, rather than being straight and more strictly parallel to the long axis of the lobes), sometimes missing at the lobe ends and only weakly organized inward lower surface: usually becoming dark brown to black at least in older parts (one species remaining pale, white to tan), often paler at the lobe ends; moderately to densely rhizinate; rhizines: usually blackened and squarrosely branched (mostly simple to furcate in one species) Apothecia: with thalline exciple asci: clavate, 8-spored ascospores: Physconia-type, brown, 1-septate, 23-38 x 12-21 µm. Pycnidia: blackened and immersed conidia: bacilliform to short-cylindrical, 4-6 x ± 1 µm Secondary metabolites: secalonic acid A, variolaric acid, or scabrosin derivatives, but often in variable concentrations or, in many species, lacking altogether Geography: primarily temperate or boreal, North America, Europe, Asia, Africa, South America, Australia Substrate: bark, wood, rock, soil or mosses.