| Sphenopholis interrupta subsp. californica (Vasey) Scribn., 1906 |
| Sphenopholis interrupta subsp. interrupta (Buckley) Scribn., 1906 |
| Sphenopholis obtusata (Michx.) Scribn., 1906 |
| Sphenopholis obtusata f. obtusata (Michx.) Scribn., 1906 |
| Sphenopholis obtusata f. purpurascens (Vasey ex Rydb. & Shear) Waterf., 1948 |
| Sphenopholis obtusata subsp. lobata (Trin.) Scribn., 1906 |
| Sphenopholis obtusata subsp. pubescens (Scribn. & Merr.) Scribn., 1906 |
| Sphenopholis obtusata var. lobata (Torr.) Scribn. ex B.L. Rob., 1908 |
| Sphenopholis obtusata var. obtusata (Michx.) Scribn., 1906 |
| Sphenopholis obtusata var. pubescens (Scribn. & Merr.) Scribn. ex B.L. Rob., 1908 |
| Sphenopholis pubescens (Scribn. & Merr.) A. Heller, 1910 |
| Sphenopholis robusta (Vasey ex L.H. Dewey) A. Heller, 1910 |
| Spirochloe Lunell, 1915 |
| Spirochloe paniculata (Nutt.) Lunell, 1915 |
| Spirotheros Raf., 1830 |
| Spirotheros melanocarpus Raf. ex B.D. Jacks., 1895 |
| Sporobolinae Benth., 1881 |
| Sporobolus R. Br., 1810 |
| Sporobolus affinis Kunth, 1829 |
| Sporobolus airoides (Torr.) Torr., 1856 |