Taxon Report

Streptanthus callistus Morrison

Mt. Hamilton jewelflower

Print Report

Taxon Summary

Streptanthus callistus, commonly known as Mt. Hamilton jewelflower, is a annual herb in the Brassicaceae that is found only in California. It occurs within Chaparral, and Cismontane woodland, growing at elevations from 600 to 790 meters. Streptanthus callistus is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Streptanthus callistus Morrison
Common Name:	Mt. Hamilton jewelflower
Family:	Brassicaceae
Element Code:	PDBRA2G0A0
USDA Plants Symbol:	STCA3
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Apr-May	Apr-May
Elevation:	600-790 (1970-2590)
General Habitats:	Chaparral, Cismontane woodland
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G1
State Rank:	S1
State List:	None
Fed List:	None
Other Status:	BLM_S
CRPR Changes:	changed from 1B.3 to 1B.2 on 2024-01-19

Occurrence Data from the CNDDB


Total Occurrences:	4
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	2
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	1

Location


California Endemic: True
California Counties and Islands: Name (Code)
Santa Clara (SCL)
Quads: Name (Quad Code)
Isabel Valley (3712135), Mt. Sizer (3712125)

Threat List Data from the CNDDB


Threat List Total:	3
EOs with Threat Listed:	Total EOs	% of EOs
	2	50 %
Non-native plant impacts	2	50%
Road/trail construction/maint.	1	25%
Erosion/runoff	1	25%

Notes



Known only from the Mt. Hamilton Range. Possibly threatened by erosion and road construction and maintenance. See Madroño 4(7):205 (1938) for original description.
Threats:

Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 3 November 2025].