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 to agglutinated, loosely appressed or firmly agglutinated at the lobe tips, 3-6(-10) cm in diam., pinnately or subpinnately lobate lobes: radiating, confluent, flat or convex but sometimes concave towards the lobe tips, 0.5-2.5 mm wide, distinctly flabellate towards the lobe tips upper surface: gray, lead-gray, bluish gray, yellowish gray, or almost white, with a punctiform or powdery, rarely patchy white pruina or not pruinose, without soralia, isidia or polysidiangia pseudocyphellae: often distinct, marginal and laminal, usually restricted to the peripheral parts of the lobes, sometimes reticulately confluent medulla: white, the lowest part sometimes orange, especially towards the lobe tips lower surface: black in center, paler towards lobe tips, erhizinate Apothecia: very common, laminal on thallus, 0.5-1 mm wide disc: jet-black, usually not or only slightly gray pruinose ascospores: brown, 1-septate, narrowly ellipsoid, 15-19 x 6-7 µm Pycnidia: immersed in warts conidia: bacilliform, 4-5 x 0.8-1.1 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 divaricatic acid and few terpenes in low concentration. Substrate and ecology: on bark, wood and rocks, from sea level to the edges of montane rain forests World distribution: in all tropical regions of both hemispheres with few collections from subtropical parts of Japan Sonoran distribution: especially in thorn forests and desert transition areas of Baja California, Baja California Sur, Sinaloa and Sonora. Notes: Most collections of Dirinaria confluens from the Sonoran region, especially those growing on smaller twigs of Fouquieria, have concrete, convex, more agglutinated (like in Hyperphyscia syncolla) and narrower lobe tips (0.3-0.5 mm broad) than specimens from other tropical countries. Transitional forms are seldom, and eventually the Sonoran population may require recognization as a separate species.