| Senecio pattersonii B.L. Turner, 1988 |
| Senecio pauciflorus Kunth, 1820 |
| Senecio peltiferus Hemsl., 1881 |
| Senecio peninsularis Vasey & Rose, 1888 |
| Senecio petasitis (Sims) DC., 1838 |
| Senecio phorodendroides L.O. Williams, 1975 |
| Senecio picridis Schauer, 1847 |
| Senecio pinacatensis Felger, 1991 |
| Senecio pinnatisectus DC., 1838 |
| Senecio platanifolius Benth., 1840 |
| Senecio platypus Greenm., 1907 |
| Senecio polypodioides (Greene) Greene, 1896 |
| Senecio porphyresthes T.M. Barkley, 1989 |
| Senecio powellii B.L. Turner, 1993 |
| Senecio praecox (Cav.) DC., 1838 |
| Senecio praecox var. morelensis (Miranda) McVaugh, 1972 |
| Senecio praecox var. tzimolensis T.M. Barkley, 1990 |
| Senecio pringlei A. Gray, 1887 |
| Senecio prionopterus B.L. Rob. & Greenm., 1896 |
| Senecio procumbens Kunth, 1820 |