Streptanthus glandulosus subsp. arkii
Kruckeberg's bristly jewelflower
(c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda · licence
Family: Brassicaceae · Type: Annual · Native
Streptanthus glandulosus subsp. arkii (Kruckeberg's bristly jewelflower) is a native California annual in the Brassicaceae family, recognized by distinctive dark maroon sepals and bicolored petals.
Kruckeberg's bristly jewelflower is a California native annual found in coastal and central western California grasslands, outcrops, and roadcuts on serpentine or metamorphic substrates at elevations of 140 to 690 meters. Flowering from March to June, this plant produces striking dark maroon to purple-black flowers with white-margined upper petals, creating a dramatic contrast of deep and pale colors. Growing 20 to 70 centimeters tall with sparsely stiff-hairy stems, it develops an upright and slightly branching form. Its mid-stem leaves are oblanceolate, flat to slightly folded lengthwise, with distinct dentate edges measuring less than five times longer than their width. The distinctive purple and white petals, combined with its serpentine habitat preference, make this jewelflower a remarkable example of California's unique botanical diversity.
Identification and appearance
Key characters: 19 sympatric species; distinctive dark maroon sepals and bicolored petals
Habitat and range
Habitat: Grasslands, outcrops, roadcuts, on serpentine or other metamorphic substrates
Elevation: 140-690 m
Bloom period
Streptanthus glandulosus subsp. arkii blooms Mar-Jun.
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 glandulosus subsp. arkii native to California?
Yes. Streptanthus glandulosus subsp. arkii is native to California (recorded as native).
When does Streptanthus glandulosus subsp. arkii bloom?
Streptanthus glandulosus subsp. arkii blooms Mar-Jun.
What plant family does Streptanthus glandulosus subsp. arkii belong to?
Streptanthus glandulosus subsp. arkii is in the Brassicaceae family, genus Streptanthus.
What habitat does Streptanthus glandulosus subsp. arkii grow in?
Streptanthus glandulosus subsp. arkii grows in Grasslands, outcrops, roadcuts, on serpentine or other metamorphic substrates.
Related species
Other California species in the same genus, family, or bioregion.
- Streptanthus glandulosus subsp. glandulosus — most beautiful jewelflower
- Streptanthus glandulosus subsp. hoffmanii — Hoffman's bristly jewelflower
- Streptanthus glandulosus subsp. josephinensis — Josephine county jewelflower
- Streptanthus glandulosus subsp. niger — Tiburon jewelflower
- Streptanthus glandulosus subsp. pulchellus — Mount tamalpais bristly jewelflower
- Streptanthus glandulosus subsp. raichei — Raiche's jewelflower
Sources: Jepson eFlora · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.