Castilleja ambigua subsp. humboldtiensis
Humboldt bay owl's-clover, Humboldt Bay Owl's-Clover
Photo: parent species Castilleja ambigua · (c) Simone Littledale, some rights reserved (CC BY) · licence
Family: Orobanchaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Castilleja ambigua subsp. humboldtiensis (Humboldt bay owl's-clover) is a native California herb in the Orobanchaceae family, recognized by salt marsh habitat and fleshy texture distinctive.
Humboldt bay owl's-clover is a rare (CNPS 1B.2) California native annual found in northern coastal California, including Humboldt, Mendocino, and Marin counties, inhabiting salt marshes at near sea level. Flowering from May to June, this plant produces pink or rose-purple flowers with yellow accents, featuring delicate lower lip teeth 2 to 3 millimeters long. Growing as a somewhat fleshy, ascending plant with few branches from its mid-stem, it develops a distinctive appearance with rounded to truncate bract tips in soft yellow-pink to rose-purple tones. Its compact structure and subtle coloration make it a distinctive inhabitant of coastal salt marsh environments. The small seeds measure 2 to 2.5 millimeters, reflecting the plant's delicate, ephemeral nature.
Identification and appearance
Key characters: 15 sympatric species, salt marsh habitat and fleshy texture distinctive
Habitat and range
Habitat: Salt marshes
Elevation: +- 0 m.
California counties: Humboldt, Marin, Mendocino
Bloom period
Castilleja ambigua subsp. humboldtiensis blooms May-Jun.
Conservation status
CNPS 1B.2
How to tell it apart
vs Triphysaria: Castilleja lacks the sharp fold in flower throat; Triphysaria has abrupt crease above lower lip.; vs Trifolium: Castilleja has tubular flowers with colorful bracts; Trifolium has round heads of pea-like flowers and three leaflets.; vs Pedicularis: Castilleja has open forward beak and colorful bracts; Pedicularis has closed hood and fern-like leaves.; vs Orthocarpus: Castilleja has open beak you can see into; Orthocarpus has closed hood covering stamens completely.; vs Epilobium: Castilleja has tubular two-lipped flowers and colorful bracts; Epilobium has four separate petals arranged in cross.
Frequently asked questions
Is Castilleja ambigua subsp. humboldtiensis native to California?
Yes. Castilleja ambigua subsp. humboldtiensis is native to California (recorded as native).
When does Castilleja ambigua subsp. humboldtiensis bloom?
Castilleja ambigua subsp. humboldtiensis blooms May-Jun.
Where in California does Castilleja ambigua subsp. humboldtiensis grow?
Castilleja ambigua subsp. humboldtiensis occurs in Humboldt, Marin, Mendocino, at elevations of +- 0 m..
What plant family does Castilleja ambigua subsp. humboldtiensis belong to?
Castilleja ambigua subsp. humboldtiensis is in the Orobanchaceae family, genus Castilleja.
Is Castilleja ambigua subsp. humboldtiensis rare or endangered?
Castilleja ambigua subsp. humboldtiensis carries California Rare Plant Rank 1B.2, state rank S2.
Related species
Other California species in the same genus, family, or bioregion.
- Castilleja ambigua subsp. insalutata — pink Johnny-nip
- Castilleja ambigua var. heckardii — Heckard's owl's- clover
- Castilleja ambigua var. meadii — Mead's owls- clover
- Castilleja angustifolia var. flavescens — northwestern paintbrush
- Castilleja applegatei — Pine indian paintbrush
- Castilleja applegatei subsp. disticha
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-10-08
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.