Science magazines
- Triangular Kidneyshell
- Triple-Ribbed Milk-vetch
- Truckee Barberry
- Tubercled Blossom Pearlymussel
- Tulotoma Snail
- Turgid Blossom Pearlymussel
- Uhiuhi
- Uinta Basin Hookless Cactus
- Umpqua River Cutthroat Trout
- Unarmored Threespine Stickleback
- Uncompahgre Fritillary Butterfly
- Upland Combshell
- Utah Prairie Dog
- Utah Valvata Snail
- Ute Ladies'-tresses
- Uvillo
- Vahl's Boxwood
- Vail Lake Ceanothus
- Valley Elderberry Longhorn Beetle
- Vancouver Island Marmot