Streptanthus howellii
Howell's jewelflower
(c) Trevor Van Loon, some rights reserved (CC BY) · licence
Family: Brassicaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Streptanthus howellii (Howell's jewelflower) is a native California herb in the Brassicaceae family, recognized by distinctive perennial habit and large maroon petals.
Howell's jewelflower is a rare (CNPS 1B.2) California native perennial found in northern Klamath Ranges in Del Norte County, occurring in open conifer and hardwood forests on rocky serpentine terrain at elevations of 600 to 800 meters. Flowering from June to July, this plant produces maroon to purple flowers 8 to 12 millimeters long with narrow petals less than 1 millimeter wide. Growing with simple or distally branched stems 30 to 80 centimeters tall, it has a glabrous appearance with a simple or branched caudex. Its leaves are distinctive, with fleshy basal leaves and mid-cauline leaves that are broadly obovate to round, ranging from 1.5 to 10 centimeters long and varying from entire to wavy or obtusely dentate. The fruit is a spreading-ascending silique 5.5 to 12 centimeters long with glabrous valves and 24 to 44 broadly oblong seeds.
Identification and appearance
Key characters: 11 sympatric species; distinctive perennial habit and large maroon petals
Habitat and range
Habitat: Open conifer/hardwood forest on rocky serpentine
Elevation: 600-800 m
Outside California: southwestern Oregon
Bloom period
Streptanthus howellii blooms Jun-Jul.
Conservation status
CNPS 1B.2
How to tell it apart
vs Caulanthus: Seed pods are flattened like sword blades versus cylindrical tubes in Caulanthus.; vs Boechera: Robust plants often over 2.5 feet with large flowers (sepals 4-8mm) versus more delicate habit.; vs Claytonia: Mustard family with 4 petals and 6 stamens versus Claytonia with 5 petals.; vs Silene: Mustard family with seed pods versus Silene with inflated capsules and opposite leaves.; vs Lonicera: Herbaceous mustard with alternate leaves versus woody vine with opposite leaves.
Frequently asked questions
Is Streptanthus howellii native to California?
Yes. Streptanthus howellii is native to California (recorded as native).
When does Streptanthus howellii bloom?
Streptanthus howellii blooms Jun-Jul.
What plant family does Streptanthus howellii belong to?
Streptanthus howellii is in the Brassicaceae family, genus Streptanthus.
Is Streptanthus howellii rare or endangered?
Streptanthus howellii carries California Rare Plant Rank 1B.2, state rank S2.
What habitat does Streptanthus howellii grow in?
Streptanthus howellii grows in Open conifer/hardwood forest on rocky serpentine.
Related species
Other California species in the same genus, family, or bioregion.
- Streptanthus insignis — San benito jewelflower
- Streptanthus insignis subsp. insignis — plumed jewelflower
- Streptanthus insignis subsp. lyonii — Arburua ranch jewelflower
- Streptanthus juneae — June's jewelflower
- Streptanthus longisiliquus — Long-fruit jewelflower
- Streptanthus medeirosii — Tejon jewelflower
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
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.