Axonopus is a largely Neotropical genus comprising about 85 species. Many classifications have been proposed based exclusively on morphological characters. Our studies, including both molecular and morphological data, suggest that Axonopus is paraphyletic due to the inclusion of Centrochloa and Ophiochloa. Considering that there are no strong morphological traits that differentiate either Centrochloa or Ophiochloa from Axonopus, we propose the following new combinations: Axonopus singularis, comb. nov., Axonopus bryoides, comb. nov., and Axonopus hydrolithicus, comb. nov. We also suggest the need to review the infrageneric classifications taking into account both morphological and molecular data.