| Aristida schiedeana Trin. & Rupr., 1842 |
| Aristida schiedeana var. minor Vasey, 1886 |
| Aristida schiedeana var. orcuttiana (Vasey) Allred & Valdés-Reyna, 1995 |
| Aristida schiedeana var. schiedeana Trin. & Rupr., 1842 |
| Aristida scribneriana Hitchc., 1924 |
| Aristida secunda Rud. ex Roem. & Schult., 1817 |
| Aristida simpliciflora Chapm., 1878 |
| Aristida simpliciflora var. texana Vasey, 1892 |
| Aristida spadicea Kunth, 1815 |
| Aristida spanospicula Allred, Valdés-Reyna & Sánchez-Ken, 1995 |
| Aristida stricta Michx., 1803 |
| Aristida stricta var. decolorata E. Fourn. ex Dávila & Sánchez-Ken, 1994 |
| Aristida stricta var. grisebachiana E. Fourn. ex Dávila & Sánchez-Ken, 1994 |
| Aristida stricta var. nealleyi Vasey, 1890 |
| Aristida subbiflora Steud., 1855 |
| Aristida subuniflora Nash, 1903 |
| Aristida tehuacanensis Sánchez-Ken & Dávila, 1994 |
| Aristida tenuifolia Hitchc., 1935 |
| Aristida tenuis (Kunth) Kunth, 1829 |
| Aristida tenuispica Hitchc., 1924 |