Three twig-growing lichen species belonging to the family Teloschistaceae from southern Patagonia are described as new to science: Marchantiana pyramus sp. nov., with minute apothecia, orange due to dominant content of emodin, M. ramulicola sp. nov., with minute olive apothecia with dominant parietin and Austroplaca thisbe sp. nov., with clear yellow apothecia also with dominant parietin. Marchantiana subpyracea, M. epibrya and M. queenslandica are new combinations for species which, so far, are known only from New Zealand and Australia. Blastenia circumpolaris is shown to be very common in Patagonia and Marchantiana asserigena is documented for the first time from the Southern Hemisphere, viz. the Falkland Islands. The genus Marchantiana is analyzed here using three genes and is shown to be closely related to Yoshimuria; although appearing as paraphyletic, a monophyletic origin cannot be ruled out. Morphology, ecology and distribution support a monophyletic treatment and Marchantiana is therefore treated as such.