| Panicum setigerum (Roth ex Roem. & Schult.) Boerl., 1890 |
| Panicum setosum Sw., 1788 |
| Panicum shallotte Ashe, 1900 |
| Panicum shastense Scribn. & Merr., 1901 |
| Panicum sloanei Griseb., 1864 |
| Panicum sonorum Beal, 1896 |
| Panicum sorghoideum Desv. ex Ham., 1825 |
| Panicum speciosum Nees ex Trin., 1826 |
| Panicum spectabile Nees ex Trin., 1826 |
| Panicum spectabile var. guadeloupense Hack., 1897 |
| Panicum sphacelatum Schumach., 1827 |
| Panicum sphaerocarpon Elliott, 1816 |
| Panicum sphaerocarpon subsp. inflatum (Scribn. & J.G. Sm.) Hitchc., 1910 |
| Panicum sphaerocarpon var. floridanum Vasey, 1889 |
| Panicum sphaerocarpum Salzm. ex Steud., 1853 |
| Panicum sphagnicola Nash, 1895 |
| Panicum spicatum (L.) Roxb., 1814 |
| Panicum spithamaeum Willd. ex Nees, 1829 |
| Panicum squamatum E. Fourn., 1885 |
| Panicum stagnatile Hitchc. & Chase, 1915 |