AbstractNumerous recent studies of lichenized fungi have uncovered hidden genetic diversity within a single phenotypic entity (so-called ‘cryptic species’). Here we report the opposite situation with vastly different morphologies apparently deriving from the same genotype.Endocenais a monotypic genus known only from southern South America. The single reported species, the terricolousE. informis, is morphologically variable; the type and other collections from the west coast of Chile being subfruticose, whereas specimens from further south and east are almost crustose in form. A sorediate terricolous lichen that is frequent on the Falkland Islands was confirmed by phylogenetic analysis of ITS rDNA and mtSSU rDNA sequences as being congeneric withE. informisand, surprisingly, both taxa were recovered as congeneric with the recently described genus and speciesChirleja buckii, which is morphologically distinct from bothE. informisand the sorediate taxon. Consequently, the genusChirlejais included in the synonymy ofEndocenaand the new combinationEndocena buckiiis proposed. BecauseE. informisand the sorediate specimens have a similar thallus structure that differs radically from that ofE. buckii, the nameE. informisvar.falklandicais proposed for the sorediate taxon. Poorly developed, incipient apothecia are also described from both varieties ofE. informis, the first time that these have been reported forEndocena. We also report two lichenicolous fungi fromE. informisvar.informis, which are the first reports of lichenicolous fungi occurring on this genus.