| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Trinematidae | 1 | 16 | 0 |
| Trinematidae | 1 | 16 | 0 |
| Triploblasts | 1 | 0 | 0 |
| Tripos furca | 0 | 4 | 0 |
| Tripos fusus | 0 | 1 | 0 |
| Tripos horridus | 0 | 2 | 0 |
| Tripos lineatus (Ehrenberg) F. Gómez 2013 | 0 | 1 | 0 |
| Tripos muelleri | 0 | 13 | 0 |
| Trochosphaeridae | 1 | 2 | 0 |
| Tubulinea | 2 | 173 | 0 |
| Ulnaria ulna | 0 | 0 | 0 |
| Ulnariaceae | 2 | 0 | 0 |
| Ulothrix carmichaelii (Harvey) P. Crouan & H. Crouan | 0 | 3 | 0 |
| Ulothrix speciosa (Carmichael) Kützing 1849 | 0 | 2 | 0 |
| Ulotrichaceae | 2 | 5 | 0 |
