TheBrizacomplex comprises 23 species from South America, Mesoamerica and Europe. They constitute a monophyletic group because of the tendency of the spikelets to be dorsiventrally compressed. A cladistic analysis of the complex was performed using 32 characters from morphology. The terminal taxa were the species of the generaBriza, Calotheca, Microbriza, PoidiumandRhomboelytrum. DactylisandArrhenatherumwere chosen to root the cladograms. Results of the cladistic analysis of the complex provide support for the ideas of Nicora and Rugolo (1981,Darwiniana23(1), 279-309):Briza, Calotheca, Microbriza, PoidiumandRhomboelytrumare supported as monophyletic groups. WithinBriza, only theChascolytrumgroup appears monophyletic, while theBrizaandUniolaegroups are paraphyletic.Poidium ambiguum, sometimes placed inPoa, is considered here asPoidium.