Perideridia oregana
Oregon yampah
(c) Ed Alverson, some rights reserved (CC BY), uploaded by Ed Alverson · licence
Family: Apiaceae · Type: Herb · Native
Perideridia oregana (Oregon yampah) is a native California herb in the Apiaceae family, recognized by bristle-like bracts.
Oregon yampah is a California native perennial found in the Klamath Ranges, northern Coast Ranges, California High Cascade Range, San Francisco Bay Area, and southern Coast Ranges in pine and oak woodland at elevations of 60 to 2,100 meters. Flowering from July to August, this plant produces white flowers in delicate umbels with 10 to 29 small blossoms. Growing 1 to 9 decimeters tall with green to bluish-green stems, it develops distinctive tuberous roots clustered in groups of two to six. Its complex basal leaves are broadly ovate, divided into intricate ternate-pinnate sections with linear or oblong leaflets 0.5 to 6 centimeters long. The plant produces small oblong fruits 3 to 6 millimeters long with delicate thread-like ribs.
Identification and appearance
Key characters: 12 sympatric species; bristle-like bracts help distinguish
Habitat and range
Habitat: Open flats or slopes, pine/oak woodland
Elevation: 60-2100 m
California counties: Del Norte, Modoc, Monterey, San Diego, Siskiyou, Trinity, Sonoma, Lassen, Butte, Glenn, Mendocino, Tehama, Napa, San Luis Obispo, San Benito, Humboldt, Contra Costa, Alameda, Lake, Colusa, Shasta, Santa Clara, Los Angeles, Fresno
Outside California: Oregon
Bloom period
Perideridia oregana blooms Jul-Aug.
How to tell it apart
vs Ligusticum: Perideridia grows from tubers in grasslands; Ligusticum grows from taproots in mountain forests.; vs Daucus: Perideridia fruits are rounded with thin ribs; Daucus fruits are bristly and form a bird's-nest cluster.; vs Eriogonum: Eriogonum is in the buckwheat family with papery flowers; Perideridia has carrot-family umbels.; vs Angelica: Perideridia has small rounded fruits; Angelica has large flattened fruits with broad wings.; vs Achillea: Achillea is in the sunflower family with flat-topped flower heads; Perideridia has carrot-family umbels.
Frequently asked questions
Is Perideridia oregana native to California?
Yes. Perideridia oregana is native to California (recorded as native).
When does Perideridia oregana bloom?
Perideridia oregana blooms Jul-Aug.
Where in California does Perideridia oregana grow?
Perideridia oregana occurs in Del Norte, Modoc, Monterey, San Diego, Siskiyou, Trinity, Sonoma, Lassen and other counties, at elevations of 60-2100 m.
What plant family does Perideridia oregana belong to?
Perideridia oregana is in the Apiaceae family, genus Perideridia.
What habitat does Perideridia oregana grow in?
Perideridia oregana grows in Open flats or slopes, pine/oak woodland.
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.