| Musineon divaricatum (Pursh) Nutt., 1840 |
| Myrrhidendron J.M. Coult. & Rose, 1894 |
| Myrrhidendron donnellsmithii J.M. Coult. & Rose, 1894 |
| Neogoezia Hemsl., 1894 |
| Neogoezia breedlovei Constance, 1987 |
| Neogoezia gracilipes (Hemsl.) Hemsl., 1894 |
| Neogoezia macvaughii Constance, 1987 |
| Neogoezia minor Hemsl., 1894 |
| Neogoezia planipetala (Hemsl.) Hemsl., 1894 |
| Neonelsonia J.M. Coult. & Rose, 1895 |
| Neonelsonia acuminata (Benth.) J.M. Coult. & Rose, 1898 |
| Neonelsonia ovata J.M. Coult. & Rose, 1895 |
| Niphogeton Schltdl., 1857 |
| Oenanthe L., 1753 |
| Oenanthe pringlei J.M. Coult. & Rose, 1895 |
| Oreomyrrhis Endl., 1839 |
| Oreomyrrhis orizabae I.M. Johnst., 1938 |
| Oreomyrrhis tolucana I.M. Johnst., 1938 |
| Osmorhiza Raf., 1819 |
| Osmorhiza bipatriata Constance & R.H. Shan, 1948 |