| Isocoma gypsophilia B.L. Turner, 1972 |
| Isocoma hartwegii (A. Gray) Greene, 1894 |
| Isocoma menziesii (Hook. & Arn.) G.L. Nesom, 1991 |
| Isocoma menziesii var. menziesii (Hook. & Arn.) G.L. Nesom, 1991 |
| Isocoma menziesii var. tridentata (Greene) G.L. Nesom, 1991 |
| Isocoma menziesii var. vernonioides (Nutt.) G.L. Nesom, 1991 |
| Isocoma pluriflora (Torr. & A. Gray) Greene, 1894 |
| Isocoma tehuacana Nesom, 1991 |
| Isocoma tenuisecta Greene, 1906 |
| Isocoma tomentosa G.L. Nesom, 1991 |
| Isocoma veneta (Kunth) Greene, 1894 |
| Isocoma vernonioides Nutt., 1840 |
| Isotypus Kunth, 1818 |
| Isotypus onoseroides Kunth, 1818 |
| Iva L., 1753 |
| Iva ambrosiifolia (A. Gray) A. Gray, 1884 |
| Iva ambrosiifolia var. ambrosiifolia (A. Gray) A. Gray, 1884 |
| Iva ambrosiifolia var. lobata (Rydb.) B.L. Turner, 1990 |
| Iva angustifolia Nutt. ex DC., 1836 |
| Iva annua L., 1753 |