| Ambrosia cordifolia (A. Gray) W.W. Payne, 1964 |
| Ambrosia cumanensis Kunth, 1818 |
| Ambrosia deltoidea (Torr.) W.W. Payne, 1964 |
| Ambrosia divaricata (Brandegee) W.W. Payne, 1964 |
| Ambrosia diversifolia (Piper) Rydb., 1922 |
| Ambrosia dumosa (A. Gray) W.W. Payne, 1964 |
| Ambrosia elatior L., 1753 |
| Ambrosia flexuosa (A. Gray) W.W. Payne, 1964 |
| Ambrosia hispida Pursh, 1814 |
| Ambrosia humi León de la Luz & Rebman, 2010 |
| Ambrosia ilicifolia (A. Gray) W.W. Payne, 1964 |
| Ambrosia johnstoniorum Henrickson, 1980 |
| Ambrosia lindheimeriana Scheele, 1849 |
| Ambrosia magdalenae (Brandegee) W.W. Payne, 1964 |
| Ambrosia monogyra (Torr. & A. Gray) Strother & B.G. Baldwin, 2002 |
| Ambrosia nivea (B.L. Rob. & Fernald) W.W. Payne, 1964 |
| Ambrosia orobanchifera Meyen, 1834 |
| Ambrosia paniculata Michx., 1803 |
| Ambrosia paniculata var. cumanensis (Kunth) O.E. Schulz, 1911 |
| Ambrosia peruviana Willd., 1805 |