| Carex ovata Burm. f., 1768 |
| Carex oxycarpa Holm, 1905 |
| Carex paneroi Reznicek & S. González, 2021 |
| Carex pellita Muhl. ex Willd., 1805 |
| Carex percostata F.J. Herm., 1950 |
| Carex perlonga Fernald, 1907 |
| Carex perstricta Mack., 1909 |
| Carex pertenuis L.H. Bailey, 1889 |
| Carex peucophila Holm, 1905 |
| Carex phleoides Cav., 1799 |
| Carex phleoides subsp. koyamae (Gómez-Laur.) Jim. Mejías, 2018 |
| 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 planilamina Reznicek & S. González, 2021 |
| Carex planostachys Kunze, 1844 |
| Carex polystachya Sw. ex Wahlenb., 1803 |
| Carex polystachya var. bartlettii (O'Neill) Standl. & Steyerm., 1953 |