Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: crustose areoles: up to 1.0 (-1.5) mm diam., adnate, weakly convex upper surface: light gray or yellowish brown, dull; soredia: absent upper cortex: up to 15 µm thick, composed of thin-walled hyphae Apothecia: up to 0.8 (-1.1) mm diam., marginal or laminal, plane; disc: black, epruinose, egyrose; margin: remaining prominent, entire or flexuose; exciple: composed of closely conglutinated hyphae, brown in inner part, brownish black in the rim, not containing crystals, K+ violet, N-; hypothecium: dark brown; epithecium: dark brown, not containing crystals, K+ violet, N-; paraphyses: without swelling and pigment cap in apical cell asci: with a well developed tholus containing an amyloid flank ascospores: common, broadly to narrowly ellipsoid, simple, 7-11.5 x 3-4.5 µm Pycnidia: sessile, black, attached to the areole or apparently directly to the substrate conidia: ellipsoid, 3-5.5 x 1.5-2.5 µm Spot tests: upper cortex and medulla K+ yellow, C+ red, KC+ red, P+ yellow Secondary metabolite: alectorialic acid. Substrate and ecology: on wood, more rarely bark, of conifers, in conifer forests at 1970-3400 m alt., not on charred substrates World distribution: Europe and North America Sonoran distribution: Arizona and Chihuahua, uncommon. Notes: The closely related boreal species H. xanthococca (Sommerf.) P. James & Gotth. Schneid. has subglobose conidia, 2.5-4 x 1.5-3 µm (see Timdal 1984b: 102, fig. 19). There are no reliable reports of H. xanthococca from North America.