Monographs Details: Porina mastoidea (Ach.) Müll.Arg.
Authority: Britton, Nathaniel L. & Millspaugh, Charles F. 1920. The Bahama Flora.

On bark, Great Bahama : widely distributed in tropical regions of both hemispheres. The material represents a form with verrucose thallus and verrucae, and the latter are somewhat constricted : but the species is so variable that it is scarcely worth while to give this form a name.