Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Life habit: lichenized Thallus: fruticose, or subfruticose ("elongate-foliose"), semi-erect to erect and caespitose, to subpendent or pendent and beardlike, up to 40-150 (-300) mm long, moderately to very flaccid, soft, and pliant, or sometimes stiffer (with hard and brittle cortex or denser medulla); weakly to richly branched, isotomic to anisotomic branches: 1-4 mm wide, in cross-section semiterete and angular or strongly flattened and ± dorsiventral; without rhizines, attached by a basal disc or draped over the substrate upper surface: ochraceous-yellowish to greenish yellow or ± greenish gray (rarely whitish mineral gray), often brownish to black at the tips; matt, epruinose, continuous, broadly wrinkled or ridged; rounded to effigurate pseudocyphellae sometimes present, white; with or without soredia, isidia cortex: thin, of branched, septate, anticlinal hyphae, cells small and indistinct medulla: white, thick, lax or dense, without strands photobiont: primary one a Trebouxia, below at least the upper cortex, secondary photobiont absent lower cortex: similar to upper one, but sometimes very thin and unpigmented lower surface: (dorsiventral species) paler than upper (often whitish), grooved, soredia absent or present along marginal rim formed by rolled-down upper surface Ascomata: apothecial, rare, marginal, lateral or terminal, shortly and stoutly stipitate, concave; disc: red-brown; thalline exciple: prominent, irregular, crenate; outer-ascomatal filaments absent; exciple: hyaline; hypothecium: hyaline; hymenium: hyaline, upper part brown or ochraceous-yellowish; paraphyses: thick, septate, unbranched; ostiolar filaments absent asci: clavate, Lecanora-type, unitunicate; tholus I+ blue; 8-spored ascospores: simple, hyaline, thin walled, 7-11 x 4-6 µm, ellipsoid, obtuse at the poles; wall thin, smooth, without distinct endospore thickening, not amyloid Conidiomata: pycnidial, rare, laminal and marginal, immersed, rounded, blackened around the ostiole; conidiophores: ± type V of Vobis (1980) conidia: acicular, formed pleurogenously Secondary metabolites: cortex with ß-orcinol depsides and usually usnic acid; medulla with orcinol depsides Geography: arctic to temperate in the Northern Hemisphere Substrate: bark, wood, or occasionally calcareous rocky soil or non-calciferous rock. Notes: It differs from the fructicose genus Ramalina in having simple spores and in usually having a flaccid, often dorsiventral, thallus. Although the foliose genus Pseudevernia can also be caespitose, the latter genus has a canaliculate lower surface, always has a gray upper surface and has stiff thallus.