Streptanthus callistus
Mount hamilton jewelflower, Mount Hamilton Jewelflower
(c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda · licence
Family: Brassicaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Streptanthus callistus (Mount hamilton jewelflower) is a native California herb in the Brassicaceae family.
Mount hamilton jewelflower is a rare (CNPS 1B.2) California native annual found in southeastern San Francisco Bay bioregion in the Mount Hamilton Range in open chaparral and gravelly sedimentary scree at elevations of 500 to 900 meters. Flowering from April to May, this plant produces purple flowers with darker purple veins approximately 8 to 11 millimeters long. Growing with bristly hairy stems 2 to 9 centimeters tall, it has a simple or branched form. Its basal leaves are oblong to obovate with dentate edges, while mid-cauline leaves are broadly ovate, sessile, and clasping at the base, with bristly surfaces. The fruit is spreading, curved upwards, 1.3 to 2.5 centimeters long with stiff-hairy valves.
Identification and appearance
Key characters: Geographically isolated with 0 sympatric species
Habitat and range
Habitat: Open chaparral, gravelly sedimentary scree
Elevation: 500-900 m
California counties: Santa Clara
Bloom period
Streptanthus callistus blooms Apr-May.
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 callistus native to California?
Yes. Streptanthus callistus is native to California (recorded as native).
When does Streptanthus callistus bloom?
Streptanthus callistus blooms Apr-May.
Where in California does Streptanthus callistus grow?
Streptanthus callistus occurs in Santa Clara, at elevations of 500-900 m.
What plant family does Streptanthus callistus belong to?
Streptanthus callistus is in the Brassicaceae family, genus Streptanthus.
Is Streptanthus callistus rare or endangered?
Streptanthus callistus carries California Rare Plant Rank 1B.2, state rank S1.
Related species
Other California species in the same genus, family, or bioregion.
- Streptanthus campestris — Southern jewelflower
- Streptanthus cordatus — Heartleaf jewelflower
- Streptanthus cordatus var. cordatus — Heartleaf jewelflower
- Streptanthus cordatus var. piutensis — Piute mountains jewelflower
- Streptanthus diversifolius — Varied-leaved jewelflower
- Streptanthus drepanoides — Sickle-fruit jewelflower
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · 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.