| Carex physorhyncha Liebm. ex Steud., 1885 |
| Carex pinetorum Liebm., 1850 |
| Carex pinetorum var. elatior Kük., 1936 |
| Carex pinophila Reznicek & S. González, 1997 |
| Carex pittieri Boeckeler, 1896 |
| Carex pityophila Mack., 1913 |
| Carex planilamina Reznicek & S. González, 2021 |
| Carex planostachys Kunze, 1844 |
| Carex polystachya Sw. ex Wahlenb., 1803 |
| Carex polystachya var. bartlettii (O'Neill) Standl. & Steyerm., 1953 |
| Carex polystachya var. madrensis (L.H. Bailey) Kük., 1909 |
| Carex polystachya var. minor Boott, 1867 |
| Carex polystachya var. polystachya Sw. ex Wahlenb., 1803 |
| Carex polysticha Boeckeler, 1869 |
| Carex potosina Hemsl., 1885 |
| Carex praegracilis W. Boott, 1884 |
| Carex pringlei L.H. Bailey, 1892 |
| Carex pseudocyperus L., 1753 |
| Carex pseudocyperus var. polysticha (Boeckeler) Kük., 1905 |
| Carex psilocarpa Steud., 1855 |