| Morronea incumbens (Swallen) Zuloaga & Scataglini, 2014 |
| Morronea parviglumis (Hack.) Zuloaga & Scataglini, 2014 |
| Morronea trichidiachnis (Döll) Zuloaga & Scataglini, 2014 |
| Moulinsia Raf., 1830 |
| Muantijamvella J.B. Phipps, 1964 |
| Muehlenbergia R. Hedw., 1806 |
| Muehlenbergia annua (Vasey) Swallen, 1947 |
| Muehlenbergia lanata (Kunth) Hitchc., 1935 |
| Muehlenbergia macroura (Kunth) Hitchc., 1935 |
| Muehlenbergia pubescens (Kunth) Hitchc., 1935 |
| Muehlenbergia ramulosa (Kunth) Swallen, 1947 |
| Muehlenbergia robusta (E. Fourn.) Hitchc., 1935 |
| Muehlenbergia utilis (Torr.) Hitchc., 1933 |
| Muhlenbergia Schreb., 1789 |
| Muhlenbergia (Clomena) (P. Beauv.) Hack., 1887 |
| Muhlenbergia abata I.M. Johnst., 1943 |
| Muhlenbergia acuminata Vasey, 1886 |
| Muhlenbergia acutifolia E. Fourn., 1885 |
| Muhlenbergia adspersa Trin., 1841 |
| Muhlenbergia affinis Trin., 1841 |