Two new genera in the Teloschistaceae, Josefpoeltia, and Xanthomendoza are described on the unique morphological characters. The genus Josefpoeltia is characterized by distinctly foliose, dorsiventral, thallus with a unique structure of both cortical layer and thalline margin of the apothecia, designated as a pseudoprosoplectenchymatous tissue, by the narrowly fusiform long conidia, and by the presence of a network of dense thin rhizines which are atypical for xanthorioid lichens. Two species are distinguished and described as new; J. boliviensis and its soredious counterpart J. sorediosa both so far known only from South America. A comparison of the taxa described here with the Xanthoria hasseana group is also provided. Xanthoria gallowayii from Argentina, Peru and Uruguay is described as a new sorediate counterpart of X. hasseana. In addition, X. hasseana is reported here for the first time from South America. The genus Xanthomendoza is separated from the genus Xanthoria on the different structure of the cortical layers, well-developed medullary plectenchyma composed of periclinally arranged hyphae, a unique structure of apothecia, narrowly ellipsoid conidia, and a special type of attachment by umbilicus hapters. Josefpoeltia, Xanthomendoza, Xanthoria gallowayii, X. hasseana, anatomy, morphology, new genera, Teloschistaceae