Find out if there are any endangered species in your state, your country, island, etc. Browse endangered species listings according to area on our planet using
the selection box below.
below. Browse the different areas in the pulldown for other countries or specific US
or Canadian states. For sea creatures and creatures found on islands in the oceans, we recommend browsing the
list.
This list is made possible through a database keyword search/filtering process which may not be 100% accurate. Therefore, all endangered species of California may not be listed here. For a complete list of endangered species in North America, browse the
.
| | Species Name | Scientific Name | Group | Range |
|---|
| 1. | Amargosa Niterwort | Nitrophila mohavensis | Plants | California, Nevada |
| 2. | Amargosa Vole | Microtus californicus scirpensis | Mammals | California |
| 3. | Antioch Dunes Evening-primrose | Oenothera deltoides ssp. howellii | Plants | California |
| 4. | Arroyo Southwestern Toad | Bufo californicus microscaphus | Amphibians | California, Mexico |
| 5. | Ashy Storm-petrel | Oceanodroma homochroa | Birds | California, Ecuador, Mexico |
| 6. | Baker's Larkspur | Delphinium bakeri | Plants | California |
| 7. | Beach Layia | Layia carnosa | Plants | California |
| 8. | Bedstraw | Galium californicum ssp. sierrae | Plants | California |
| 9. | Bedstraw | Galium buxifolium | Plants | California |
| 10. | Ben Lomond Spineflower | Chorizanthe pungens var. hartwegiana | Plants | California |
| 11. | Ben Lomond Wallflower | Erysimum teretifolium | Plants | California |
| 12. | Bighorn Sheep | Ovis canadensis | Mammals | California |
| 13. | Black Abalone | Haliotis cracherodii | Snails | California, Mexico (Baja California) |
| 14. | Black Salamander | Aneides flavipunctatus | Amphibians | California, Oregon |
| 15. | Black Sea Bass | Stereolepis gigas | Fishes | California, Mexico |
| 16. | Black Toad | Anaxyrus exsul | Amphibians | California |
| 17. | Blunt-nosed Leopard Lizard | Gambelia silus | Reptiles | California |
| 18. | Bocaccio Rockfish | Sebastes paucispinus | Fishes | Canada, Mexico, United States |
| 19. | Boisduval's Blue Butterfly | Icaricia icarioides | Insects | California, Oregon |
| 20. | Bonytail Chub | Gila elegans | Fishes | Arizona, California, Colorado, Nevada, Utah, Wyoming |
| 21. | Boreal Toad | Anaxyrus boreas | Amphibians | Canada, Mexico, United States (California) |
| 22. | Braunton's Milk-vetch | Astragalus brauntonii | Plants | California |
| 23. | Brown Pelican | Pelecanus occidentalis | Birds | Coastal Central and South America, USA (Carolinas to Texas, California, Oregon, Washington), West Indies |
| 24. | Buena Vista Lake Ornate Shrew | Sorex ornatus relictus | Mammals | California |
| 25. | Burke's Goldfields | Lasthenia burkei | Plants | California |
| 26. | California Bay Pea Crab | Parapinnixa affinis | Crustaceans | California |
| 27. | California Condor  | Gymnogyps californianus | Birds | Arizona, California, Oregon |
| 28. | California Freshwater Shrimp | Syncaris pacifica | Crustaceans | California |
| 29. | California Giant Salamander | Dicamptodon ensatus | Amphibians | California |
| 30. | California Jewelflower | Caulanthus californicus | Plants | California |
| 31. | California Orcutt Grass | Orcuttia californica | Plants | California |
| 32. | California Red Tree Mouse | Arborimus pomo | Mammals | California |
| 33. | California Seablite | Suaeda californica | Plants | California |
| 34. | California Taraxacum | Taraxacum californicum | Plants | California |
| 35. | California Tiger Salamander | Ambystoma californiense | Amphibians | California |
| 36. | Calistoga Allocarya | Plagiobothrys strictus | Plants | California |
| 37. | Callippe Silverspot Butterfly | Speyeria callippe callippe | Insects | California |
| 38. | Carex albida | Carex albida | Plants | California |
| 39. | Carson Wandering Skipper | Pseudocopaeodes eunus obscurus | Insects | California, Nevada |
| 40. | Cassin's Finch | Carpodacus cassinii | Birds | Canada, Mexico, United States |
| 41. | Catalina Island Mountain-Mahogany | Cercocarpus traskiae | Plants | California |
| 42. | Catalina Mountain Snail | Radiocentrum avalonense | Snails | California |
| 43. | Chestnut-collared Longspur | Calcarius ornatus | Birds | North America (including United States) |
| 44. | Chinook Salmon | Oncorhynchus tshawytscha | Fishes | California (Sacramento River) in the winters |
| 45. | Ciervo Scarab Beetle | Aegialia concinna | Insects | California |
| 46. | Clapper Rail | Rallus longirostris | Birds | Arizona, California |
| 47. | Clara Hunt's Milk-vetch | Astragalus clarianus | Plants | California |
| 48. | Clouded Salamander | Aneides ferreus | Amphibians | California, Oregon |
| 49. | Clover Lupine | Lupinus tidestromii | Plants | California |
| 50. | Coachelia Giant Sand Treader Cricket | Macrobaenetes valgum | Insects | California |
| 51. | Coachella Valley Fringe-toed Lizard | Uma inornata | Reptiles | California |
| 52. | Coachella Valley Milk-vetch | Astragalus lentiginosus var. coachellae | Plants | California |
| 53. | Coastal Dunes Milk-vetch | Astragalus tener var. titi | Plants | California |
| 54. | Coho Salmon | Oncorhynchus kisutch | Fishes | California |
| 55. | Colorado Pikeminnow | Ptychocheilus lucius | Fishes | Arizona, California, Colorado, Mexico, Nevada, New Mexico, Utah, Wyoming |
| 56. | Common Sawfish | Pristis pristis | Fishes | Africa, Asia, Australia, Central and South America, Europe, Mexico, United States |
| 57. | Conservancy Fairy Shrimp | Branchinecta conservatio | Crustaceans | California |
| 58. | Contra Costa Goldfields | Lasthenia conjugens | Plants | California |
| 59. | Contra Costa Wallflower | Erysimum capitatum var. angustatum | Plants | California |
| 60. | Cougar | Puma concolor | Mammals | North and Central America |
| 61. | Coyote Ceanothus | Caenothus ferrisae | Plants | California |
| 62. | Cushenbury Milk-vetch | Astragalus albens | Plants | California |
| 63. | Cushenbury Oxytheca | Oxytheca parishii var. goodmaniana | Plants | California |
| 64. | Cushion Buckwheat | Eriogonum ovalifolium | Plants | California, Nevada |
| 65. | Del Mar Manzanita | Arctostaphylos glandulosa ssp. crassifolia | Plants | California, Mexico |
| 66. | Delhi Sands Flower-loving Fly | Rhaphiomidas terminatus abdominalis | Insects | California |
| 67. | Delta Green Ground Beetle | Elaphrus viridis | Insects | California |
| 68. | Delta Smelt | Hypomesus transpacificus | Fishes | California |
| 69. | Desert Pupfish | Cyprinodon macularius | Fishes | Arizona, California, Mexico |
| 70. | Desert Slender Salamander | Batrachoseps aridus | Amphibians | California |
| 71. | El Segundo Blue Butterfly | Euphilotes battoides allyni | Insects | California |
| 72. | Eureka Dune Grass | Swallenia alexandrae | Plants | California |
| 73. | Eureka Valley Evening-primrose | Oenothera avita ssp. eurekensis | Plants | California |
| 74. | Few-flowered Navarretia | Navarretia leucocephala ssp. pauciflora | Plants | California |
| 75. | Fountain Thistle | Cirsium fontinale | Plants | California |
| 76. | Franklin's Bumble Bee | Bombus franklini | Insects | California, Oregon |
| 77. | Fraternal Snail | Micrarionta feralis | Snails | California |
| 78. | Frilled Shark | Chlamydoselachus anguineus | Fishes | Angola, Australia, Chile, France, Guyana, Japan, Mauritania, Morocco, Namibia, New Zealand, Norway, Portugal (Madeira), South Africa, Spain, United Kingdom, United States (California) |
| 79. | Gambel's Watercress | Rorippa gambellii | Plants | California |
| 80. | Gaviota Tarplant | Deinandra increscens ssp. villosa | Plants | California |
| 81. | Geothallus tuberosus | Geothallus tuberosus | Plants | California |
| 82. | Giant Kangaroo Rat | Dipodomys ingens | Mammals | California |
| 83. | Gila Monster | Heloderma suspectum | Reptiles | Mexico, United States |
| 84. | Gilia | Gilia tenuiflora | Plants | California |
| 85. | Gray Wolf | Canis lupus | Mammals | Mexico, United States |
| 86. | Greater Sage-grouse | Centrocercus urophasianus | Birds | Canada, United States |
| 87. | Green Sturgeon | Acipenser medirostris | Fishes | Alaska, California, Canada (British Columbia), Mexico, Oregon |
| 88. | Greene's Tuctoria | Tuctoria greenei | Plants | California |
| 89. | Gulf Grouper | Mycteroperca jordani | Fishes | California, Mexico |
| 90. | Hairy Orcutt Grass | Orcuttia pilosa | Plants | California |
| 91. | Hammerhead Shark | Sphyrna mokarran | Fishes | Africa, Asia, Australia, Central and South America, Middle East, Oceanic, United States |
| 92. | Hartweg's Golden Sunburst | Pseudobahia bahiifolia | Plants | California |
| 93. | Heermann's Gull | Larus heermanni | Birds | Arizona, California, Canada, Guatemala, Mexico, Oregon, Washington |
| 94. | Hermes Copper | Lycaena hermes | Insects | California, Mexico |
| 95. | Hesperodiaptomus californiensis | Hesperodiaptomus californiensis | Crustaceans | California |
| 96. | Hickman's Potentilla | Potentilla hickmanii | Plants | California |
| 97. | Hoffmann's Rock-cress | Arabis hoffmannii | Plants | California |
| 98. | Howell's Spineflower | Chorizanthe howellii | Plants | California |
| 99. | Indian Knob Mountain Balm | Eriodictyon altissimum | Plants | California |
| 100. | Inyo Mountains Salamander | Batrachoseps campi | Amphibians | California |
| 101. | Ione Buckwheat | Eriogonum apricum | Plants | California |
| 102. | Ischnura gemina | Ischnura gemina | Insects | California |
| 103. | Island Barberry | Berberis pinnata ssp. insularis | Plants | California |
| 104. | Island Fox | Urocyon littoralis | Mammals | California |
| 105. | Island Malacothrix | Malacothrix squalida | Plants | California |
| 106. | Island Phacelia | Phacelia insularis ssp. insularis | Plants | California |
| 107. | Island Scrub-jay | Aphelocoma insularis | Birds | California |
| 108. | Jaguar | Panthera onca | Mammals | Arizona, California, Central and South America, Louisiana, Mexico, New Mexico, Texas |
| 109. | Kangaroo Rat | Dipodomys nitratoides | Mammals | California |
| 110. | Keck's Checker-mallow | Sidalcea keckii | Plants | California |
| 111. | Kelso Giant Sand Treader Cricket | Macrobaenetes kelsoensis | Insects | California |
| 112. | Kelso Jerusalem Cricket | Ammopelmatus kelsoensis | Insects | California |
| 113. | Kern Mallow | Eremalche kernensis | Plants | California |
| 114. | Kern Plateau Salamander | Batrachoseps robustus | Amphibians | California |
| 115. | Kern Shoulderband | Helminthoglypta callistoderma | Snails | California |
| 116. | Kneeland Prairie Penny-cress | Thlaspi californicum | Plants | California |
| 117. | La Graciosa Thistle | Cirsium loncholepis | Plants | California |
| 118. | Laguna Mountains Skipper | Pyrgus ruralis lagunae | Insects | California |
| 119. | Lake County Stonecrop | Parvisedum leiocarpum | Plants | California |
| 120. | Lane Mountain Milk-vetch | Astragalus jaegerianus | Plants | California |
| 121. | Lange's Metalmark Butterfly | Apodemia mormo langei | Insects | California |
| 122. | Large-flowered Fiddleneck | Amsinckia grandiflora | Plants | California |
| 123. | Least Bell's Vireo | Vireo bellii pusillus | Birds | California, Mexico |
| 124. | Least Tern | Sterna antillarum | Birds | Bahamas, Central America (winters), Greater and Lesser Antilles, Mexico, Northern South America, USA (California, including the Miss. R. Basin), Atlantic Gulf Coasts |
| 125. | Loch Lomond Coyote Thistle | Eryngium constancei | Plants | California |
| 126. | Lompoc Grasshopper | Trimerotropis occulens | Insects | California |
| 127. | Lompoc Yerba Santa | Eriodictyon capitatum | Plants | California |
| 128. | Longhorn Fairy Shrimp | Branchinecta longiantenna | Crustaceans | California |
| 129. | Lost River Sucker | Deltistes luxatus | Fishes | California, Oregon |
| 130. | Lotis Blue Butterfly | Lycaeides argyrognomon lotis | Insects | California |
| 131. | Lyon's Pentachaeta | Pentachaeta lyonii | Plants | California |
| 132. | Many-flowered Navarretia | Navarretia leucocephala ssp. plieantha | Plants | California |
| 133. | Marbled Murrelet | Brachyramphus marmoratus | Birds | Canada, Mexico, United States |
| 134. | McDonald's Rock-cress | Arabis mcdonaldiana | Plants | California |
| 135. | Menzies' Wallflower | Erysimum menziesii | Plants | California |
| 136. | Metcalf Canyon Jewelflower | Streptanthus albidus ssp. albidus | Plants | California |
| 137. | Mexican Flannelbush | Fremontodendron mexicanum | Plants | California, Mexico |
| 138. | Mexican Long-tongued Bat | Choeronycteris mexicana | Mammals | Arizona, California, El Salvador, Guatemala, Honduras, Mexico, Nevada, New Mexico, Texas |
| 139. | Middlekauf's Shieldback Katydid | Idiostatus middlekaufi | Insects | California |
| 140. | Modoc Sucker | Catostomus microps | Fishes | California |
| 141. | Mohave Tui Chub | Gila bicolor mohavensis | Fishes | California |
| 142. | Monterey Clover | Trifolium trichocalyx | Plants | California |
| 143. | Morro Bay Kangaroo Rat | Dipodomys heermanni morroensis | Mammals | California |
| 144. | Morro Shoulderband Snail | Helminthoglypta walkeriana | Snails | California |
| 145. | Mountain Yellow-legged Frog | Rana muscosa | Amphibians | USA - Southern California DPS |
| 146. | Mt. Hermon June Beetle | Polyphylla barbata | Insects | California |
| 147. | Munz's Onion | Allium munzii | Plants | California |
| 148. | Napa Bluegrass | Poa napensis | Plants | California |
| 149. | Nelson's Antelope Squirrel | Ammospermophilus nelsoni | Mammals | California |
| 150. | Nevin's Barberry | Berberis nevinii | Plants | California |
| 151. | Nipomo Mesa Lupine | Lupinus nipomensis | Plants | California |
| 152. | Northern Abalone | Haliotis kamtschatkana | Snails | Alaska, California, Canada (British Columbia), Oregon, Washington |
| 153. | Ohlone Tiger Beetle | Cicindela ohlone | Insects | California |
| 154. | Olive-sided Flycatcher | Contopus cooperi | Birds | Central and South America, North America (including United States) |
| 155. | Orcutt's Spineflower | Chorizanthe orcuttiana | Plants | California |
| 156. | Oregon Checker-mallow | Sidalcea oregana | Plants | California |
| 157. | Otay Mesa-mint | Pogogyne nudiuscula | Plants | California, Mexico (Baja California) |
| 158. | Owens Pupfish | Cyprinodon radiosus | Fishes | California |
| 159. | Owens Tui Chub | Gila bicolor snyderi | Fishes | California |
| 160. | Pacific Pocket Mouse | Perognathus longimembris pacificus | Mammals | California |
| 161. | Pacific Pond Turtle | Actinemys marmorata | Reptiles | California, Mexico, Oregon, Washington |
| 162. | Palmate-bracted Bird's-beak | Cordylanthus palmatus | Plants | California |
| 163. | Palos Verdes Blue Butterfly | Glaucopsyche lygdamus palosverdesensis | Insects | California |
| 164. | Pedate Checker-mallow | Sidalcea pedata | Plants | California |
| 165. | Pennell's Bird's-beak | Cordylanthus tenuis ssp. capillaris | Plants | California |
| 166. | Pine Hill Ceanothus | Ceanothus roderickii | Plants | California |
| 167. | Pine Hill Flannelbush | Fremontodendron californicum ssp. decumbens | Plants | California |
| 168. | Pismo Clarkia | Clarkia speciosa ssp. immaculata | Plants | California |
| 169. | Pitkin Marsh Lily | Lilium pardalinum ssp. pitkinense | Plants | California |
| 170. | Point Arena Mountain Beaver | Aplodontia rufa nigra | Mammals | California |
| 171. | Port Conception Jerusalem Cricket | Ammopelmatus muwu | Insects | California |
| 172. | Presidio Clarkia | Clarkia franciscana | Plants | California |
| 173. | Presidio Manzanita | Arctostaphylos hookeri var. ravenii | Plants | California |
| 174. | Prickly Pear | Opuntia treleasei | Plants | California |
| 175. | Prickly Shark | Echinorhinus cookei | Fishes | Australia, California, China, Hawaii, New Zealand, Palau, Peru, Taiwan |
| 176. | Quercus dumosa | Quercus dumosa | Plants | California, Mexico |
| 177. | Quino Checkerspot Butterfly | Euphydryas editha quino | Insects | California, Mexico |
| 178. | Razorback Sucker | Xyrauchen texanus | Fishes | Arizona, California, Colorado, Mexico, Nevada, New Mexico, Utah, Wyoming |
| 179. | Red Tree Vole | Arborimus longicaudus | Mammals | California, Oregon |
| 180. | Red-crowned Parrot | Amazona viridigenalis | Birds | Mexico, Puerto Rico, US (TX, FL, CA) |
| 181. | Right Whale | Balaena japonica | Mammals | Canada (British Columbia), China, Japan, Korea, Mexico (Baja California), Russia, Taiwan, United States and Hawaii |
| 182. | Riparian Brush Rabbit | Sylvilagus bachmani riparius | Mammals | California |
| 183. | Riparian Woodrat | Neotoma fuscipes riparia | Mammals | California |
| 184. | Robust Spineflower | Chorizanthe robusta | Plants | California |
| 185. | Sacramento Anthicid Beetle | Anthicus sacramento | Insects | United States |
| 186. | Sacramento Orcutt Grass | Orcuttia viscida | Plants | California |
| 187. | Sacramento Splittail | Pogonichthys macrolepidotus | Fishes | California |
| 188. | Salt Marsh Bird's-beak | Cordylanthus maritimus ssp. maritimus | Plants | California, Mexico (Baja California) |
| 189. | Salt Marsh Harvest Mouse | Reithrodontomys raviventris | Mammals | California |
| 190. | San Bernardino Bluegrass | Poa atropurpurea | Plants | California |
| 191. | San Bernardino Merriam's Kangaroo Rat | Dipodomys merriami parvus | Mammals | California |
| 192. | San Bernardino Mountains Bladderpod | Lesquerella kingii ssp. bernardina | Plants | California |
| 193. | San Bruno Elfin Butterfly | Callophrys mossii bayensis | Insects | California |
| 194. | San Clemente Island Broom | Lotus dendroideus ssp. traskiae | Plants | California |
| 195. | San Clemente Island Bush-mallow | Malacothamnus clementinus | Plants | California |
| 196. | San Clemente Island Indian Paintbrush | Castilleja grisea | Plants | California |
| 197. | San Clemente Island Larkspur | Delphinium variegatum ssp. kinkiense | Plants | California |
| 198. | San Clemente Island Woodland-star | Lithophragma maximum | Plants | California |
| 199. | San Clemente Loggerhead Shrike | Lanius ludovicianus mearnsi | Birds | California |
| 200. | San Diego Ambrosia | Ambrosia pumila | Plants | California, Mexico |
| 201. | San Diego Button-celery | Eryngium aristulatum var. parishii | Plants | California |
| 202. | San Diego Fairy Shrimp | Branchinecta sandiegonensis | Crustaceans | California |
| 203. | San Diego Mesa-mint | Pogogyne abramsii | Plants | California |
| 204. | San Francisco Garter Snake | Thamnophis sirtalis tetrataenia | Reptiles | California |
| 205. | San Francisco Lessingia | Lessingia germanorum | Plants | California |
| 206. | San Jacinto Valley Crownscale | Atriplex coronata var. notatior | Plants | California |
| 207. | San Joaquin Kit Fox | Vulpes macrotis mutica | Mammals | California |
| 208. | San Joaquin Wooly-threads | Monolopia congdonii | Plants | California |
| 209. | San Mateo Thornmint | Acanthomintha obovata ssp. duttonii | Plants | California |
| 210. | San Mateo Woolly Sunflower | Eriophyllum latilobum | Plants | California |
| 211. | Sandwort | Arenaria paludicola | Plants | California |
| 212. | Santa Ana River Woolly-star | Eriastrum densifolium ssp. sanctorum | Plants | California |
| 213. | Santa Barbara Island Liveforever | Dudleya traskiae | Plants | California |
| 214. | Santa Clara Valley Dudleya | Dudleya setchellii | Plants | California |
| 215. | Santa Cruz Cypress | Cupressus abramsiana | Plants | California |
| 216. | Santa Cruz Island Bush-mallow | Malacothamnus fasciculatus var. nesioticus | Plants | California |
| 217. | Santa Cruz Island Fringepod | Thysanocarpus conchuliferus | Plants | California |
| 218. | Santa Cruz Island Malacothrix | Malacothrix indecora | Plants | California |
| 219. | Santa Cruz Island Rock-cress | Sibara filifolia | Plants | California |
| 220. | Santa Cruz Long-toed Salamander | Ambystoma macrodactylum croceum | Amphibians | California |
| 221. | Santa Monica Mountains Grasshopper | Trimerotropis occidentaloides | Insects | California |
| 222. | Santa Rosa Island Manzanita | Arctostaphylos confertiflora | Plants | California |
| 223. | Scotts Valley Polygonum | Polygonum hickmanii | Plants | California |
| 224. | Sea Otter | Enhydra lutris | Mammals | Canada, Japan, Mexico, Russia, United States |
| 225. | Sebastopol Meadowfoam | Limnanthes vinculans | Plants | California |
| 226. | Shasta Crayfish | Pacifastacus fortis | Crustaceans | California |
| 227. | Short-tailed Albatross | Phoebastria albatrus | Birds | Arkansas, Bering Sea, California, Canada, China, Hawaii, Japan, Mexico, North Pacific Ocean, Oregon, Russia, Taiwan, Washington |
| 228. | Shortnose Sucker | Chasmistes brevirostris | Fishes | California, Oregon |
| 229. | Showy Indian Clover | Trifolium amoenum | Plants | California |
| 230. | Sierra Nevada Yellow-legged Frog | Rana sierrae | Amphibians | California |
| 231. | Siskiyou Mountains Salamander | Plethodon stormi | Amphibians | California, Oregon |
| 232. | Slender-horned Spineflower | Dodecahema leptoceras | Plants | California |
| 233. | Slender-petaled Mustard | Thelypodium stenopetalum | Plants | California |
| 234. | Smith's Blue Butterfly | Euphilotes enoptes smithi | Insects | California |
| 235. | Soft Bird's-Beak | Cordylanthus mollis ssp. mollis | Plants | California |
| 236. | Soft-leaved Paintbrush | Castilleja mollis | Plants | California |
| 237. | Solano Grass | Tuctoria mucronata | Plants | California |
| 238. | Sonoma Alopecurus | Alopecurus aequalis var. sonomensis | Plants | California |
| 239. | Sonoma Spineflower | Chorizanthe valida | Plants | California |
| 240. | Sonoma Sunshine | Blennosperma bakeri | Plants | California |
| 241. | Sooty Crayfish | Pacifastacus nigrescens | Crustaceans | California |
| 242. | Southwestern Willow Flycatcher | Empidonax traillii extimus | Birds | Arizona, California, Colorado, Mexico, New Mexico, Texas, Utah |
| 243. | Sphaerocarpos drewei | Sphaerocarpos drewei | Plants | California |
| 244. | Stebbins' Morning-glory | Calystegia stebbinsii | Plants | California |
| 245. | Steelhead | Oncorhynchus mykiss | Fishes | (endangered population southern California Coast), North Pacific Ocean from the Kamchatka Peninsula in Asia to the northern Baja Peninsula |
| 246. | Steller Sea-lion | Eumetopias jubatus | Mammals | Alaska, California, Canada, North Pacific Ocean, Oregon, Russia, Washington |
| 247. | Stephen's Kangaroo Rat | Dipodomys stephensi | Mammals | California |
| 248. | Stephen's Kangaroo Rat | Dipodomys cascus | Mammals | California |
| 249. | Streptocephalus woottoni | Streptocephalus woottoni | Crustaceans | California |
| 250. | Suisun Thistle | Cirsium hydrophilum var. hydrophilum | Plants | California |
| 251. | Tiburon Jewelflower | Streptanthus niger | Plants | California |
| 252. | Tiburon Paintbrush | Castilleja affinis ssp. neglecta | Plants | California |
| 253. | Tidewater Goby | Eucyclogobius newberryi | Fishes | California |
| 254. | Tight Coin | Ammonitella yatesii | Snails | California |
| 255. | Tricolored Blackbird | Agelaius tricolor | Birds | Mexico, United States (California) |
| 256. | Triple-ribbed Milk-vetch | Astragalus tricarinatus | Plants | California |
| 257. | Unarmored Threespine Stickleback | Gasterosteus aculeatus williamsoni | Fishes | California |
| 258. | Ventura Marsh Milk-vetch | Astragalus pycnostachyus var. lanosissimus | Plants | California |
| 259. | Vernal Pool Tadpole Shrimp | Lepidurus packardi | Crustaceans | California |
| 260. | Vine Hill Clarkia | Clarkia imbricata | Plants | California |
| 261. | Wandering Salamander | Aneides vagrans | Amphibians | California, Canada (British Columbia) |
| 262. | Western Lily | Lilium occidentale | Plants | California, Oregon |
| 263. | White Abalone | Haliotis sorenseni | Snails | North America (West Coast from Point Conception, CA, USA, to Punta Abreojos, Baja Californa, Mexico) |
| 264. | White-eared Pocket Mouse | Perognathus alticolus | Mammals | California |
| 265. | White-rayed Pentachaeta | Pentachaeta bellidiflora | Plants | California |
| 266. | Willowy Monardella | Monardella linoides ssp. viminea | Plants | California, Mexico |
| 267. | Woolly Meadowfoam | Limnanthes floccosa | Plants | California |
| 268. | Yadon's Piperia | Piperia yadonii | Plants | California |
| 269. | Yellow Larkspur | Delphinium luteum | Plants | California |
| 270. | Yosemite Toad | Anaxyrus canorus | Amphibians | California |
| 271. | Yreka Phlox | Phlox hirsuta | Plants | California |
| 272. | Zayante Band-winged Grasshopper | Trimerotropis infantilis | Insects | California |
| 273. | Zerene Fritillary | Speyeria zerene | Insects | California |
