Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: foliose to subfruticose, up to 5 cm broad but usually smaller, irregularly lobate lobes: ± convex, variable in width, up to 2 (-3) mm, often ascending, sometimes imbricate with whitish cilia along margins upper surface: grayish white to gray, sometimes reddish in herbarium caused by poor drying; soredia and isidia absent upper cortex: prosoplectenchymatous medulla: white lower cortex: absent lower surface: white, ± canaliculated, arachnoid, appearing sorediate, rhizinate; rhizines, marginal, simple to irregularly branched Apothecia: ± abundant, 1-2 (-5) mm wide, subterminal and substipitate to stipitate and thus appearing terminal, with ± well developed squamules on margin; disc: brown to dark brown, ± pruinose asci: subclavate to clavate, 8-spored ascospores: brown, l-septate, ellipsoid, Pachysporaria type with sporoblastidia (26-) 29.5-35 (-35.5) x (13-) 13.5-16 (-17) µm Pycnidia: ± abundant conidia: bacilliform, 4-5 x 1 µm Spot tests: cortex K+ yellow, C-, KC-, P+ yellow; medulla K+ yellow to red, C-, KC-, P+ orange Secondary metabolites: cortex with atranorin and chloroatranorin; medulla with atranorin, zeorin and salazinic acid (major) and norstictic acid (trace or accessory). Substrate and ecology: on twigs and small branches in oak and pine forests World distribution: widespread but not common species known from southern USA, Central and South America, Africa and Asia Sonoran distribution: SE Arizona and the Sierra Madre Occidental region of Chihuahua. Notes: No material, from which Bélangers figures were made, seems to be left. We have seen no material from Réunion, but among the material seen from Africa, that from the Usambara Mountains is the most similar to the figure description. The species usually is fairly small and consequently the epitype is also small. Additional material from the Usambara Mountains. (Moberg 1484f and Santesson 23335a, UPS) show the variation of the species. H. podocarpa is the only species present in the area belonging to the group Podocarpae. The spores are a bit smaller than in the material from East Africa. A similar species, but one with soralia, is H. galactophylla, that is known from southeastern North America, and Central and South America.