List of species endemic to Mendocino County, California

This is a list of plant and animal species, subspecies and varieties that are endemic to Mendocino County, California, or to Mendocino and no more than one neighboring county.

• Chorizanthe howellii, a flowering plant in the buckwheat family found only near Fort Bragg
• Cuscuta pacifica var. papillata, a parasitic plant found only in the salt marshes of Mendocino county
• Eriogonum kelloggii, a species of buckwheat found only on Red Mountain near Leggett
• Harmonia guggolziorum, a flowering aster found in two locations near Hopland
• Limnanthes bakeri, a meadowfarm plant known in only 20 locations near Willits
• Pinus contorta var. bolanderi, the Mendocino shore pine tree, a variety of the more widespread lodgepole pine
• Sedum eastwoodiae, a flower in the stonecrop family found only on Red Mountain near Ukiah

• Aplodontia rufa nigra (Point Arena mountain beaver), a mid-sized rodent regarded as a living fossil and found only near Point Arena
• Opercularia ampluscolonia, a protist that inhabits ponds in Mendocino County
• Plebejus idas lotis (Lotis blue butterfly), a possibly extinct gossamer-winged butterfly last recorded near Mendocino town in 1983^[1]
• Speyeria zerene behrensii (Behrens' silverspot butterfly), found only near Point Arena

In addition, the following are endemic to an area contained in Mendocino and only one neighboring county:

• Arctostaphylos mendocinoensis, a species of manzanita found only in Mendocino and Sonoma counties
• Astragalus agnicidus, a species of milkvetch found only in Mendocino and Humboldt counties
• Cupressus pygmaea, a species of cypress tree found only in Mendocino and Sonoma counties
• Lewisia stebbinsii, a flowering purslane found only in Mendocino and Trinity counties
• Veratrum fimbriatum, the fringed corn lily, a relative of the lily found only in Mendocino and Sonoma counties

• Helminthoglypta arrosa pomoensis, the Pomo Bronze Shoulderband, a 39 mm (1.5 in) land snail found in redwood forests in Mendocino County (in the Big River, Navarro River, and Russian Gulch watersheds) and Sonoma County

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Nature of Mendocino County, California.

• Natural history of Mendocino County, California