| Marina victoriae León de la Luz, 2002 |
| Mariosousa Seigler & Ebinger, 2006 |
| Mariosousa acatlensis (Benth.) Seigler & Ebinger, 2006 |
| Mariosousa centralis (Britton & Rose) Seigler & Ebinger, 2006 |
| Mariosousa compacta (Rose) Seigler & Ebinger, 2006 |
| Mariosousa coulteri (Benth.) Seigler & Ebinger, 2006 |
| Mariosousa dolichostachya (S.F. Blake) Seigler & Ebinger, 2006 |
| Mariosousa durangensis (Britton & Rose) Seigler & Ebinger, 2006 |
| Mariosousa heterophylla (Benth.) Seigler & Ebinger, 2018 |
| Mariosousa mammifera (Schltdl.) Seigler & Ebinger, 2006 |
| Mariosousa millefolia (S. Watson) Seigler & Ebinger, 2006 |
| Mariosousa russelliana (Britton & Rose) Seigler & Ebinger, 2006 |
| Mariosousa salazarii (Britton & Rose) Seigler & Ebinger, 2006 |
| Mariosousa sericea (M. Martens & Galeotti) Seigler & Ebinger, 2006 |
| Mariosousa usumacintensis (Lundell) Seigler & Ebinger, 2006 |
| Mariosousa willardiana (Rose) Seigler & Ebinger, 2006 |
| Martiusia J.A. Schultes & J.H. Schultes, 1822 |
| Martiusia mariana (L.) Small, 1933 |
| Medicago L., 1753 |
| Medicago apiculata Willd., 1802 |