Numerous 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. Endocena is a monotypic genus known only from southern South America. The single reported species, the terricolous E. 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 with E. informis and, surprisingly, both taxa were recovered as congeneric with the recently described genus and species Chirleja buckii, which is morphologically distinct from both E. informis and the sorediate taxon. Consequently, the genus Chirleja is included in the synonymy of Endocena and the new combination Endocena buckii is proposed. Because E. informis and the sorediate specimens have a similar thallus structure that differs radically from that of E. buckii, the name E. informis var. falklandica is proposed for the sorediate taxon. Poorly developed, incipient apothecia are also described from both varieties of E. informis, the first time that these have been reported for Endocena. We also report two lichenicolous fungi from E. informis var. informis, which are the first reports of lichenicolous fungi occurring on this genus.