| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Umbilicaria vellea (L.) Hoffm. | 0 | 0 | 1 |
| Umbilicaria virginis Schaer. | 0 | 0 | 1 |
| Umbilicariaceae | 1 | 0 | 0 |
| Umbilicariales | 1 | 0 | 0 |
| Umbonulidae Canu 1904 | 1 | 0 | 0 |
| Unciola Say 1818 | 2 | 0 | 0 |
| Unciola leucopis (Krøyer 1845) | 0 | 0 | 1 |
| Unciola planipes Norman 1867 | 0 | 0 | 1 |
| Undinella Sars G. O. 1900 | 1 | 0 | 0 |
| Undinella oblonga Sars G. O. 1900 | 0 | 0 | 1 |
| Urasterias Verrill 1909 | 1 | 0 | 0 |
| Urasterias lincki (Müller & Troschel 1842) | 0 | 0 | 1 |
| Uria Brisson 1760 | 1 | 0 | 0 |
| Uria lomvia (Linnaeus 1758) | 0 | 0 | 1 |
| Uristidae Hurley 1963 | 2 | 0 | 0 |
