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

Thallus: foliose, ±appressed, loosely appressed at the lobe tips, up to 8 cm in diam., pinnately or subpinnately lobate lobes: radiating, confluent, flat or convex, but usually concave towards the lobe tips, rarely convex throughout, 0.2-3 mm wide, confluent, distinctly flabellate towards the lobe tips upper surface: gray, bluish gray, almost white or stramineous, slightly pruinose or without a pruina, without soralia, isidia or polysidiangia pseudocyphellae: distinct, laminal and marginal, usually restricted to the peripheral parts of the lobes, sometimes reticulately confluent medulla: white throughout or the lowest part orange lower surface: black in center, paler towards lobe tips, erhizinate Apothecia: often present, laminal on thallus, 0.5-1.5 mm wide disc: black, slightly grayish pruinose, sometimes without a pruina ascospores: brown, 1-septate, narrowly ellipsoid, 12-19 x 5-7 µm Pycnidia: immersed in warts conidia: bacilliform, 3-4 x 1 µm Spot tests: upper cortex K+ yellow, C-, KC-, P+ yellow; medulla upper and lower part K-, C-, KC-, P- Secondary metabolites: upper cortex with atranorin, medulla with sekikaic acid (major), ramalinolic acid (minor) and few terpenes in low concentration. Substrate and ecology: on bark and wood, near the sea World distribution: tropical and subtropical regions of North, Central and South America with scattered collections from Asia Sonoran distribution: especially in thorn forests and deciduous forests of Baja California Sur and Sinaloa.