| Muhlenbergia schreberi J.F. Gmel., 1791 |
| Muhlenbergia schreberi subsp. schreberi J.F. Gmel., 1791 |
| Muhlenbergia schreberi var. palustris (Scribn.) Scribn. ex B.L. Rob., 1908 |
| Muhlenbergia scoparia Vasey, 1893 |
| Muhlenbergia seatonii Scribn., 1893 |
| Muhlenbergia setarioides E. Fourn., 1886 |
| Muhlenbergia setifolia Vasey, 1882 |
| Muhlenbergia setosa (Kunth) Trin., 1824 |
| Muhlenbergia shepherdii (Vasey) Swallen, 1947 |
| Muhlenbergia simplex (Scribn.) Rydb., 1905 |
| Muhlenbergia sinuosa Swallen, 1947 |
| Muhlenbergia solisii (G.A. Levin) P.M. Peterson, 2010 |
| Muhlenbergia spatha Columbus, 2010 |
| Muhlenbergia speciosa Vasey, 1886 |
| Muhlenbergia spicata (Spreng.) Kunth, 1829 |
| Muhlenbergia spiciformis Trin., 1841 |
| Muhlenbergia sprengelii Trin., 1824 |
| Muhlenbergia squarrosa (Trin.) Rydb., 1909 |
| Muhlenbergia stipoides (Kunth) Trin., 1824 |
| Muhlenbergia straminea Hitchc., 1913 |