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Taxon  Report  
Castilleja ambigua  (Hook. & Arn.) T.I. Chuang & Heckard  var. humboldtiensis  (D.D. Keck) J.M. Egger
Humboldt bay owl's-clover
Castilleja ambigua var. humboldtiensis is an annual herb that is native to California, and endemic (limited) to California.
California Rare Plant Rank: 1B.2 (rare, threatened, or endangered in CA and elsewhere).
Siskiyou Del Norte Modoc Humboldt Shasta Lassen Trinity Plumas Tehama Butte Mendocino Glenn Sierra Yuba Lake Nevada Colusa Placer Sutter El Dorado Yolo Alpine Napa Sonoma Sacramento Mono Amador Solano Calaveras Tuolumne San Joaquin Marin Contra Costa Alameda Santa Cruz Mariposa Madera San Francisco San Mateo Merced Fresno Stanislaus Santa Clara Inyo San Benito Tulare Kings Monterey San Bernardino San Luis Obispo Kern Santa Barbara Ventura Los Angeles Riverside Orange San Diego Imperial
Observation Search
~99 records in California
yellowone or more occurrences
within a 7.5-minute quadrangle
Parent: Castilleja ambigua
Genus: Castilleja
Family: Orobanchaceae  
(Scrophulariaceae)
Category: angiosperm  
PLANTS group:Dicot
Jepson eFlora section: eudicot

Wetlands: Occurs usually in wetlands, occasionally in non wetlands

Habitat: salt-marsh, coastal

Communities: Coastal Salt Marsh, wetland-riparian

Name Status:
Accepted by CNPS + POWO
Alternate Names:
CNPSCastilleja ambigua ssp. humboldtiensis
Information about  Castilleja ambigua var. humboldtiensis from other sources
Nursery availability from CNPLX
Commercial availability unknown.
Photos on Calflora

Photos on CalPhotos

Google Images

Photos on iNaturalist

ID Tips on PlantID.net

[explorer.natureserve.org] Threats, Endangered: Endemic to California, Castilleja ambigua ssp. humboldtiensis occurs in Humboldt, Mendocino, Marin, and Pacific Ocean Counties and is threatened by coastal development, cattle trampling, human recreational use, and ORV's. Only a few sites are protected and management plans may not exist. The coastal salt marsh habitat of this taxon is threatened in general. (link added by Mary Ann Machi)


Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals. [web application]. 2025. The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 07/13/2025).