Last updated October 1, 2009
| Name | Family | Nativity |
| Ulmus americana | Ulmaceae | E North America |
| Ulmus parvifolia | Ulmaceae | China, Japan |
| Ulmus sp. | Ulmaceae | |
| Uncarina roeoseliana | Pedaliaceae | Madagascar |
| Urginea maritima | Hyacinthaceae | Mediterranean, Portugal |
| Ursulaea tuitensis | Bromeliaceae | Mexico(Jalisco) |
