| Muhlenbergia sprengelii Trin., 1824 |
| Muhlenbergia squarrosa (Trin.) Rydb., 1909 |
| Muhlenbergia stipoides (Kunth) Trin., 1824 |
| Muhlenbergia straminea Hitchc., 1913 |
| Muhlenbergia stricta (J. Presl) Kunth, 1833 |
| Muhlenbergia strictior Scribn. ex Beal, 1896 |
| Muhlenbergia subalpina Vasey, 1885 |
| Muhlenbergia subaristata Swallen, 1936 |
| Muhlenbergia subbiflora Hitchc., 1935 |
| Muhlenbergia subtilis Nees, 1847 |
| Muhlenbergia sylvatica Torr., 1834 |
| Muhlenbergia sylvatica var. flexuosa Vasey, 1879 |
| Muhlenbergia sylvatica var. pringlei Scribn., 1882 |
| Muhlenbergia sylvatica var. setarioides (E. Fourn.) Beal, 1896 |
| Muhlenbergia tarahumara P.M. Peterson & Columbus, 2009 |
| Muhlenbergia tenella (Kunth) Trin., 1824 |
| Muhlenbergia tenuifolia (Kunth) Kunth, 1829 |
| Muhlenbergia tenuifolia (Kunth) Trin., 1824 |
| Muhlenbergia tenuissima (J. Presl) Kunth, 1833 |
| Muhlenbergia texana Buckley, 1862 |