| Ageratina irrasa (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina isolepis (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina jaliscensis (B.L. Rob.) Gage ex B.L. Turner, 1997 |
| Ageratina jalpana B.L. Turner, 1996 |
| Ageratina jalpanserra B.L. Turner, 2014 |
| Ageratina jocotepecana B.L. Turner, 1996 |
| Ageratina josepaneroi B.L. Turner, 1997 |
| Ageratina juxtlahuacensis Panero & Villaseñor, 1998 |
| Ageratina kochiana B.L. Turner, 1992 |
| Ageratina lapsensis B.L. Turner, 2009 |
| Ageratina lasia (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina lasioneura (Hook. & Arn.) R.M. King & H. Rob., 1972 |
| Ageratina leiocarpa (B.L. Rob.) Gage ex B.L. Turner, 1997 |
| Ageratina lemmonii (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina leptodictyon (A. Gray) R.M. King & H. Rob., 1970 |
| Ageratina liebmannii (Sch. Bip. ex Klatt) R.M. King & H. Rob., 1970 |
| Ageratina ligustrina (DC.) R.M. King & H. Rob., 1970 |
| Ageratina loeseneri (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina lucida (Ortega) R.M. King & H. Rob., 1970 |
| Ageratina macdonaldii B.L. Turner, 1990 |