| 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 |
| Ageratina prunellifolia (Kunth) R.M. King & H. Rob., 1970 |
| Ageratina purpusii (Brandegee) R.M. King & H. Rob., 1970 |
| Ageratina queretaroana B.L. Turner, 1987 |
| Ageratina rafaelensis (J.M. Coult.) R.M. King & H. Rob., 1970 |
| Ageratina ramireziorum (Espinosa) B.L. Turner, 1987 |
| Ageratina ramonensis (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina repens (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina reserva B.L. Turner, 2012 |