| Muhlenbergia hintonii Swallen, 1950 |
| Muhlenbergia hirtula Steud., 1854 |
| Muhlenbergia holwayorum Hitchc., 1927 |
| Muhlenbergia huachucana Vasey, 1892 |
| Muhlenbergia idahoensis H. St. John, 1937 |
| Muhlenbergia imperfecta (Nash) Columbus, 2010 |
| Muhlenbergia implicata (Kunth) Kunth, 1829 |
| Muhlenbergia implicata (Kunth) Trin., 1824 |
| Muhlenbergia involuta Swallen, 1932 |
| Muhlenbergia iridifolia Soderstr., 1967 |
| Muhlenbergia jaime-hintonii P.M. Peterson & Valdés-Reyna, 1999 |
| Muhlenbergia jaliscana Swallen, 1958 |
| Muhlenbergia lanata (Kunth) Hitchc., 1937 |
| Muhlenbergia laxa Hitchc., 1935 |
| Muhlenbergia laxiflora Scribn., 1894 |
| Muhlenbergia lemmonii Scribn., 1890 |
| Muhlenbergia leptoura (Piper) Hitchc., 1935 |
| Muhlenbergia liebmannii E. Fourn., 1886 |
| Muhlenbergia ligulata (E. Fourn.) Scribn. & Merr., 1901 |
| Muhlenbergia lindheimeri Hitchc., 1934 |