Clarkia williamsonii
Fort Miller clarkia
(c) My-Lan Le, some rights reserved (CC BY) · licence
Family: Onagraceae · Type: Herb · Native
Clarkia williamsonii (Fort Miller clarkia) is a native California herb in the Onagraceae family, recognized by large fan-shaped petals, bowl-shaped corolla, erect buds.
Fort Miller clarkia is a California native annual found in northern and central Sierra Nevada, southern Sierra Nevada Foothills, and Tehachapi regions in foothill woodland and yellow-pine forest at elevations of 400 to 2,000 meters. Flowering from April to September, this plant produces lavender flowers with white centers and distinctive purple spots, typically 10 to 30 millimeters wide in a delicate fan shape. Growing up to one meter tall with erect stems covered in fine soft hairs, it features narrow linear to lanceolate leaves measuring 2 to 7 centimeters long. Its leaves have short petioles up to 10 millimeters long, with an open inflorescence bearing erect flower buds. The flower hypanthium ranges 7 to 13 millimeters long, with unique bowl-shaped petals that occasionally appear in a uniform wine-red color.
Identification and appearance
Key characters: 35 sympatric species; key features are large fan-shaped petals, bowl-shaped corolla, erect buds
Habitat and range
Habitat: Foothill woodland, yellow-pine forest
Elevation: 400-2000 m
California counties: Tuolumne, Mariposa, Amador, Madera, El Dorado, Placer, Fresno, Tulare, Calaveras, Butte, Nevada, San Joaquin, Shasta, Kern, Stanislaus, Alameda, Santa Barbara, Riverside, Sacramento
Bloom period
Clarkia williamsonii blooms Apr-Sep.
How to tell it apart
vs Epilobium: Clarkia seeds lack a hair tuft and its petals are broad, often clawed or lobed; Epilobium and Chamerion have seeds bearing a tuft of silky hairs and long, thin capsules.; vs Oenothera: Clarkia flowers are pink to lavender-purple and its buds nod before opening; Oenothera flowers are generally yellow (or white), larger, and open at dusk.; vs Camissonia: Clarkia petals are pink-purple, often fan-shaped or lobed with a distinct claw; Camissonia and Camissoniopsis have yellow, unlobed petals.; vs Sidalcea: Clarkia has 4 petals, an inferior ovary, and a 4-lobed stigma; Sidalcea (checkerbloom) has 5 petals, a superior ovary, and a central mallow staminal column.; vs Gayophytum: Clarkia is showy with petals 10-35 mm; Gayophytum has minute white-to-pink flowers only a few mm across on thread-like branches.
Frequently asked questions
Is Clarkia williamsonii native to California?
Yes. Clarkia williamsonii is native to California (recorded as native).
When does Clarkia williamsonii bloom?
Clarkia williamsonii blooms Apr-Sep.
Where in California does Clarkia williamsonii grow?
Clarkia williamsonii occurs in Tuolumne, Mariposa, Amador, Madera, El Dorado, Placer, Fresno, Tulare and other counties, at elevations of 400-2000 m.
What plant family does Clarkia williamsonii belong to?
Clarkia williamsonii is in the Onagraceae family, genus Clarkia.
What habitat does Clarkia williamsonii grow in?
Clarkia williamsonii grows in Foothill woodland, yellow-pine forest.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.