| Aristida peninsularis Hitchc., 1924 |
| Aristida peruviana Beetle, 1975 |
| Aristida petersonii Allred & Valdés-Reyna, 1995 |
| Aristida pseudospadicea F.T. Hubb., 1913 |
| Aristida purpurascens Poir., 1810 |
| Aristida purpurascens var. alabamensis Trin. & Rupr., 1842 |
| Aristida purpurascens var. glaucissima Kearney ex Scribn. & Ball, 1901 |
| Aristida purpurascens var. minor Vasey, 1892 |
| Aristida purpurascens var. tenuispica (Hitchc.) Allred, 1986 |
| Aristida purpurea Nutt., 1837 |
| Aristida purpurea f. brownii (Warnock) Allred & Valdés-Reyna, 1995 |
| Aristida purpurea subsp. robusta (Merr.) Piper, 1906 |
| Aristida purpurea var. aequiramea (Scheele) Merr., 1901 |
| Aristida purpurea var. berlandieri Trin. & Rupr., 1842 |
| Aristida purpurea var. californica Vasey, 1892 |
| Aristida purpurea var. capillarifolia Merr., 1901 |
| Aristida purpurea var. curvifolia (E. Fourn.) Allred, 1984 |
| Aristida purpurea var. fendleri Vasey, 1874 |
| Aristida purpurea var. fendleriana (Steud.) Vasey, 1892 |
| Aristida purpurea var. glauca (Nees) A.H. Holmgren & N.H. Holmgren, 1977 |