| Stipa virescens Kunth, 1815 |
| Stipa virginica Pers., 1805 |
| Stipa virlettii E. Fourn., 1886 |
| Stipagrostis Nees, 1832 |
| Stipagrostis (Nees) Trin. & Rupr., 1842 |
| Stipeae Dumort., 1824 |
| Stipinae Griseb., 1844 |
| Streptachne Kunth, 1815 |
| Streptochaeta Schrad. ex Nees, 1829 |
| Streptochaeta sodiroana Hack., 1890 |
| Streptochaeta spicata Schrad. ex Nees, 1829 |
| Streptochaeta spicata subsp. spicata Schrad. ex Nees, 1829 |
| Streptochaeteae C.E. Hubb., 1934 |
| Streptogyna P. Beauv., 1812 |
| Streptogyna americana C.E. Hubb., 1956 |
| Streptogyneae C.E. Calderón & Soderstr., 1980 |
| Strombodurus Steud., 1841 |
| Stylagrostis Mez, 1922 |
| Stylagrostis (Mez) Rúgolo & X. Villavicencio, 1995 |
| Suardia Schrank, 1820 |