| Tessaria sericea (Nutt.) Shinners, 1967 |
| Tetracanthus A. Rich., 1850 |
| Tetracarpum Moench, 1802 |
| Tetracarpum guatemalense Rydb., 1914 |
| Tetracarpum pringlei (S. Watson) Rydb., 1914 |
| Tetracarpum virgatum Rydb., 1914 |
| Tetracarpum wislizeni (A. Gray) Rydb., 1914 |
| Tetrachyron Schltdl., 1847 |
| Tetrachyron brandegeei (Greenm.) Wussow & Urbatsch, 1980 |
| Tetrachyron chimalapanum B.L. Turner, 2006 |
| Tetrachyron discolor (A. Gray) Wussow & Urbatsch, 1980 |
| Tetrachyron grayi (Klatt) Wussow & Urbatsch, 1980 |
| Tetrachyron manicatum Schltdl., 1847 |
| Tetrachyron oaxacana B.L. Turner, 1986 |
| Tetrachyron omissum Rzed. & Calderón, 2008 |
| Tetrachyron orizabaensis (Klatt) Wussow & Urbatsch, 1980 |
| Tetrachyron orizabaensis var. orizabaensis (Klatt) Wussow & Urbatsch, 1980 |
| Tetrachyron orizabaensis var. websteri (Wussow & Urbatsch) Wussow & Urbatsch, 1980 |
| Tetrachyron paneroi B.L. Turner, 2016 |
| Tetrachyron torresii B.L. Turner, 1985 |