Siskiyou County is a county located in the northwestern part of the U.S. state of California. As of the 2020 census, the population was 44,076. Its county seat is Yreka and its highest point is Mount Shasta. It falls within the Cascadia bioregion.
The Klamath Mountains are a rugged and lightly-populated mountain range in northwestern California and southwestern Oregon in the western United States. As a mountain system within both the greater Pacific Coast Ranges and the California Coast Ranges, the Klamath Mountains have a varied geology, with substantial areas of serpentinite and marble, and a climate characterized by moderately cold winters with very heavy snowfall and warm, very dry summers with limited rainfall, especially in the south. As a consequence of the geology and soil types, the mountains harbor several endemic or near-endemic trees, forming one of the largest collections of conifers in the world. The mountains are also home to a diverse array of fish and animal species, including black bears, large cats, owls, eagles, and several species of Pacific salmon. Millions of acres in the mountains are managed by the United States Forest Service. The northernmost and largest sub-range of the Klamath Mountains are the Siskiyou Mountains.
Iris series Californicae are a series of the genus Iris, in Iris subg. Limniris. They are commonly known as Pacific Coast iris (PCI), or Pacific Coast natives (PCN).
Abies bracteata, the Santa Lucia fir or bristlecone fir, is the rarest fir in North America, and according to some, the world. It is confined to steep-sided slopes and the bottoms of rocky canyons in the Santa Lucia Mountains, in the Big Sur region on the central coast of California, United States.
Hesperocyparis bakeri, previously known Cupressus bakeri, with the common names Baker cypress, Modoc cypress, or Siskiyou cypress, is a rare species of western cypress tree endemic to a small area across far northern California and extreme southwestern Oregon, in the western United States.
The Cascade–Siskiyou National Monument is a United States national monument that protects 114,000 acres (46,134 ha) of forest and grasslands at the junction of the Cascade Range and the Siskiyou Mountains in Southwestern Oregon and Northwestern California, United States. The monument is managed by the Bureau of Land Management as part of the National Landscape Conservation System. It was established in a presidential proclamation by President Bill Clinton on June 9, 2000 and expanded by President Barack Obama on January 12, 2017.
Iris chrysophylla, the yellowleaf iris, is a wildflower which ranges from midwestern and southern Oregon west of the Cascades and south to the crest of the Siskiyou Mountains in northern California. The yellowleaf iris grows up to 5,500 feet (1,700 m) elevation, most commonly in open, coniferous forests.
Vancouveria is a small group of plants belonging to the barberry family described as a genus in 1834. The three plants in this genus are known generally as inside-out flowers, and they are endemic to the West Coast of the United States. The genus was named after George Vancouver, English navigator and explorer.
- Vancouveria chrysanthaGreene – golden inside-out flower – California, Oregon
- Vancouveria hexandra(Hook.) C.Morren & Decne. – white inside-out flower – northwestern California, western Oregon, southwestern Washington
- Vancouveria planipetalaCalloni – redwood inside-out flower – California as far south as Monterey County, southwestern Oregon
Iris purdyi is a species of iris known by the common name Purdy's iris, named after Carl Purdy. It is found in the redwood forests of California and into southern Oregon, and hence is also known as the redwood iris. The plant flowers from April to June.
Erigeron cervinus is a North American species of flowering plant in the family Asteraceae known by the common names Siskiyou fleabane and Siskiyou daisy.
Fritillaria glauca is a species of fritillary known by the common names Siskiyou fritillary and Siskiyou missionbells.
Allium cratericola is a species of wild onion known by the common name Cascade onion. It is endemic to California, where is an uncommon member of the flora in several of the state's mountain ranges, including the northern and southern California Coast Ranges, the western Transverse Ranges, Klamath Mountains, and the Sierra Nevada foothills. Its range covers much of the state, from Riverside County to Siskiyou County.
Allium siskiyouense is a North American species of wild onion known by the common name Siskiyou onion. It is native to the Klamath Mountains and nearby ranges of northern California and Oregon. It grows in serpentine and other rocky soil types.
Amphicarpaea bracteata is an annual to perennial vine in the legume family, native to woodland, thickets, and moist slopes in eastern North America.
Liatris bracteata, commonly known as the bracted blazing star, or South Texas gayfeather, is a species of flowering plant in the family Asteraceae. It is native to Texas in the United States, where it is found in coastal prairies, roadsides, and along railroads with clay or sandy loam soils. This species is of conservation concern in its native range due to habitat loss.
Eriogonum siskiyouense is a rare species of wild buckwheat known by the common name Siskiyou buckwheat.
Phlox hirsuta, the Yreka phlox or hairy phlox, is a species of phlox. It is a small flowering plant that grows in the serpentine soils of Siskiyou County, California and is the official city flower of Yreka, California, after which it is named.
Sabulina stolonifera is a rare species of flowering plant in the pink family known by the common names Scott Mountain sandwort and stolon sandwort.
Aletris bracteata is a plant species native to southern Florida and to the Bahamas. It grows in the Everglades and other wet areas very close to sea level. Some hybridization between this species and the yellow-flowered A. lutea has been noted.
Eulonchus tristis is a species of small-headed flies in the family Acroceridae.
