| Cactaceae | |
Mammillaria formosa subsp. chionocephala
| (J.A. Purpus) D.R. Hunt | Mammillaria Postscripts 7: 3 | 1998 |
| Cactaceae | |
Mammillaria formosa subsp. formosa
| | | |
| Cactaceae | |
Mammillaria formosa subsp. microthele
| (Muehlenpf.) D.R. Hunt | Mammillaria Postscripts 6: 9 | 1997 |
| Cactaceae | |
Mammillaria formosa subsp. pseudocrucigera
| (R.T. Craig) D.R. Hunt | Mammillaria Postscripts 6: 10 | 1997 |