| Pereilema crinitum J. Presl, 1830 |
| Pereilema crinitum var. cirratum E. Fourn., 1886 |
| Pereilema crinitum var. crinitum J. Presl, 1830 |
| Pereilema setarioides E. Fourn., 1886 |
| Perlaria Heist. ex Fabr., 1763 |
| Perulifera A. Camus, 1928 |
| Peyritschia E. Fourn., 1886 |
| Peyritschia deyeuxioides (Kunth) Finot, 2003 |
| Peyritschia humilis (Louis-Marie) Finot, 2003 |
| Peyritschia koelerioides (Peyr.) E. Fourn., 1886 |
| Peyritschia pinetorum (Swallen) Finot & P.M. Peterson, 2006 |
| Peyritschia pringlei (Scribn.) S.D. Koch, 1979 |
| Phacellaria Willd. ex Steud., 1841 |
| Phacellaria panicea Willd. ex Steud., 1841 |
| Phaenospermateae Renvoize & Clayton, 1985 |
| Phalarella Boiss., 1844 |
| Phalaridantha St.-Lag., 1889 |
| Phalaridinae Rchb., 1828 |
| Phalaridium Nees & Meyen, 1841 |
| Phalaris L., 1753 |