Science magazines
- White Wartyback Pearlymussel
- White-haired Goldenrod
- White-rayed Pentachaeta
- Wide-leaf Warea
- Willamette Daisy
- Willowy Monardella
- Winged Mapleleaf
- Winkler Cactus
- Wireweed
- Wood Stork
- Woodland Caribou
- Woundfin
- Wright Fishhook Cactus
- Wyoming Toad
- Xylosma Crenatum
- Yadon's Piperia
- Yaqui Catfish
- Yaqui Chub
- Yellow Blossom Pearlymussel
- Yellow Larkspur