| Ptilostephium coronopifolium Kunth, 1818 |
| Pyrethrum Medik., 1775 |
| Pyrethrum parthenium (L.) Sm., 1800 |
| Pyrrhopappus DC., 1838 |
| Pyrrhopappus carolinianus (Walter) DC., 1838 |
| Pyrrhopappus pauciflorus (D. Don) DC., 1838 |
| Pyrrhopappus sessaeanus DC., 1838 |
| Pyrrocoma Hook., 1833 |
| Pyrrocoma menziesii Hook. & Arn., 1838 |
| Rafinesquia Nutt., 1841 |
| Rafinesquia californica Nutt., 1841 |
| Rafinesquia neomexicana A. Gray, 1853 |
| Ratibida Raf., 1817 |
| Ratibida coahuilensis B.L. Turner, 1988 |
| Ratibida columnifera (Nutt.) Wooton & Standl., 1915 |
| Ratibida latipalearis E.L. Richards, 1964 |
| Ratibida mexicana (S. Watson) W.M. Sharp, 1935 |
| Ratibida peduncularis (Torr. & A. Gray) Barnhart, 1897 |
| Ratibida tagetes (L.E. James) Barnhart, 1897 |
| Rayjacksonia R.L. Hartm. & M.A. Lane, 1996 |