| Metcalfia Conert, 1960 |
| Metcalfia mexicana (Scribn.) Conert, 1960 |
| Michelaria Dumort., 1823 |
| Micrairoideae Pilg., 1956 |
| Microchloa R. Br., 1810 |
| Microchloa indica (L. f.) P. Beauv., 1812 |
| Microchloa kunthii Desv., 1831 |
| Micropogon Pfeiff., 1847 |
| Milaria Trin., 1826 |
| Mildbraediochloa Butzin, 1971 |
| Miliastrum Fabr., 1759 |
| Miliinae Dumort., 1829 |
| Milium L., 1753 |
| Milium barbipulvinatum (Nash) Lunell, 1915 |
| Milium bicolor (L.) Cav., 1803 |
| Milium capillare (L.) Moench, 1794 |
| Milium ciliare (Retz.) Moench, 1802 |
| Milium ciliatum Muhl., 1817 |
| Milium colonum (L.) Moench, 1794 |
| Milium coloratum (L.) Moench, 1794 |