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

Thallus: crustose, verruculose, rimose, 0.2-0.4 mm thick surface: white to ash-gray, esorediate Apothecia: sessile, 1-1.5 mm in diam. disc: orange to red-brown, epruinose margin: concolorous with the thallus, rarely the disc color spreading into it, persistent, smooth, shiny, initially +thick, later thinner and crowded back, crenate to flexuous exciple: red, thin epihymenium: bright red (K+ red or magenta to purple) hymenium: hyaline, 70-110 µm tall; paraphyses: strongly branched and reticulate, gelatinous, with only slightly swollen apices; hypothecium: hyaline asci: clavate, 8-spored ascospores: hyaline, transversely 7-11 septate, 45-75 x 3-5.5 µm Pycnidia: in small, thallus-colored warts, 0.1-0.2 mm in diam., with flesh-colored ostioles conidia: filiform, 7-11 x 0.9-1.2 µm Spot tests: thallus K+ yellow, C-, KC+ yellow, P- Secondary metabolites: atranorin, placodiolic acid and russulone. Substrate and ecology: on bark, especially Quercus, in oak-pine woodlands World distribution: western Mexico Sonoran distribution: Sonora and Sinaloa. Notes: Haematomma dolichosporum is characterized by the verruculose, white to gray thallus, sessile apothecia with orange to red-brown discs, 7-11-septate spores, and the presence of placodiolic acid in addition to russulone. It differs from H. infuscum in having larger ascospores with more numerous septa, and shorter conidia.