Chromosome numbers and meiotic behavior of 60 individuals of American Paniceae, Poaceae, are provided, including six previously uncounted species: Axonopus andinus G. A. Black (2n  =  20), A. iridifolius (Poepp.) G. A. Black (2n  =  20), Dichanthelium hebotes (Trin.) Zuloaga (2n  =  18), Paspalum geminiflorum Steud. (2n  =  ca. 20), P. heterotrichon Trin. (2n  =  20), and Setaria tenacissima Schrad. ex Schult. (2n  =  36). Of the remaining 54 counts, 17 correspond to new ploidy levels in species of Echinochloa P. Beauv., Eriochloa Kunth, Hymenachne P. Beauv., Panicum L., Parodiophyllochloa Zuloaga & Morrone, Paspalum L., and Setaria P. Beauv., and 37 are confirmations of previous reports.