| Pappophorum pusillum (Rendle) K. Schum., 1901 |
| Pappophorum saccharoides Griseb., 1879 |
| Pappophorum subbulbosum Arechav., 1896 |
| Pappophorum vaginatum Buckley, 1866 |
| Pappophorum vaginatum Phil., 1870 |
| Pappophorum vincentianum J.A. Schmidt, 1852 |
| Pappophorum wrightii S. Watson, 1883 |
| Parafestuca E.B. Alexeev, 1985 |
| Parapholiinae Caro, 1982 |
| Parapholis C.E. Hubb., 1946 |
| Parapholis incurva (L.) C.E. Hubb., 1946 |
| Paratristachya C.E. Hubb., 1936 |
| Parodiochloa C.E. Hubb., 1981 |
| Parodiophyllochloa Zuloaga & Morrone, 2008 |
| Parodiophyllochloa cordovensis (E. Fourn.) Zuloaga & Morrone, 2008 |
| Parodiophyllochloa ovulifera (Trin.) Zuluaga & Morrone, 2008 |
| Pascopyrum Á. Löve, 1980 |
| Pascopyrum smithii (Rydb.) Á. Löve, 1980 |
| Pascopyrum smithii (Rydb.) Barkworth & D.R. Dewey, 1985 |
| Paspalanthium Desv., 1831 |