Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.
Thallus: crustose, granulose to areolate areoles: (0.3-)0.5-0.8(-1.2) mm wide, rather thick, irregularly shaped, granulose to coralloid or warty upper surface: blackish with dark green tinge, dull to slightly glossy, soon uneven, roughly warty anatomy: small-celled paraplectenchymatous lower surface: attached by rhizohyphae originating from the entire lower surface Apothecia: sessile, 1-2 per areole, 0.3-0.5(-0.6) mm wide; margin: thalline, thin, soon receding, disc: testaceous, plane to slightly convex, soon with a central umbo, finally several times umbonate proper exciple: distinct, thick, outer layers pale reddish brown, internally hyaline; epihymenium: pale hymenium: hyaline, up to 150 µm tall, soon divided by intrusions of sterile hyphae forming 3-4 chambers in vertical sections and causing the umbonate appearance of the apothecial disc in surface view, IKI+ blue; subhymenium: hyaline, IKI+ blue; hypothecium: ±pale yellow or hyaline, IKI- ascus: 8-spored ascospores: hyaline, simple, ellipsoid to broad ellipsoid, 20-25 x 10-12.5 µm, thin walled Pycnidia: not observed conidia: not observed Spot tests: all negative Secondary products: none detected. Substrate and ecology: on mortar and siliceous rock World distribution: Brazil, North America Sonoran distribution: a single report from Baja California Sur. Notes: The apothecia of Leprocollema americanum are distinctive. The brick-colored discs soon become umbonate, corresponding to the divided appearance of the hymenium. The discs are surrounded by a thick concolorous proper exciple. The thalline margin is soon receding giving the apothecia an almost biatorine appearance. Hence, the species is unlikely to be confused with members of Psorotichia, Porocyphus and Pyrenopsis.