| Ageratina palmeri (A. Gray) Gage ex B.L. Turner, 1997 |
| Ageratina parayana (Espinosa) B.L. Turner, 1987 |
| Ageratina pauciflora B.L. Turner, 2013 |
| Ageratina paupercula (A. Gray) R.M. King & H. Rob., 1970 |
| Ageratina pazcuarensis (Kunth) R.M. King & H. Rob., 1970 |
| Ageratina pelotropha (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina pendula Panero & Villaseñor, 1997 |
| Ageratina peracuminata R.M. King & H. Rob., 1978 |
| Ageratina perezii B.L. Turner, 1989 |
| Ageratina petiolaris (Moc. & Sessé ex DC.) R.M. King & H. Rob., 1970 |
| Ageratina photina (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina pichinchensis (Kunth) R.M. King & H. Rob., 1970 |
| Ageratina pichinchensis var. bustamenta (DC.) R.M. King & H. Rob., 1990 |
| Ageratina pichinchensis var. pichinchensis (Kunth) R.M. King & H. Rob., 1970 |
| Ageratina plethadenia (Standl. & Steyerm.) R.M. King & H. Rob., 1972 |
| Ageratina pochutlana B.L. Turner, 2006 |
| Ageratina porriginosa (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina potosina B.L. Turner, 1987 |
| Ageratina pringlei (B.L. Rob. & Greenm.) R.M. King & H. Rob., 1970 |
| Ageratina prionobia (B.L. Rob.) R.M. King & H. Rob., 1970 |