| Muhlenbergia leptoura (Piper) Hitchc., 1935 |
| Muhlenbergia liebmannii E. Fourn., 1886 |
| Muhlenbergia ligulata (E. Fourn.) Scribn. & Merr., 1901 |
| Muhlenbergia lindheimeri Hitchc., 1934 |
| Muhlenbergia longifolia Vasey, 1893 |
| Muhlenbergia longiglumis Vasey, 1893 |
| Muhlenbergia longiligula Hitchc., 1934 |
| Muhlenbergia longiseta Benth., 1840 |
| Muhlenbergia lucida Swallen, 1936 |
| Muhlenbergia lycuroides Vasey ex Beal, 1896 |
| Muhlenbergia macrotis (Piper) Hitchc., 1935 |
| Muhlenbergia macroura (Kunth) Hitchc., 1935 |
| Muhlenbergia madrensis M.E. Jones, 1912 |
| Muhlenbergia magna Hitchc., 1935 |
| Muhlenbergia majalcensis P.M. Peterson, 1989 |
| Muhlenbergia marshii I.M. Johnst., 1943 |
| Muhlenbergia matudae Sohns, 1956 |
| Muhlenbergia metcalfei M.E. Jones, 1912 |
| Muhlenbergia mexicana (L.) Trin., 1824 |
| Muhlenbergia meziana Hitchc., 1935 |