Taxon Report

Streptanthus howellii Wats.

Howell's jewelflower

Print Report

©Rick York and CNPS

Taxon Summary

Streptanthus howellii, commonly known as Howell's jewelflower, is a perennial herb in the Brassicaceae that is found in California and elsewhere. It occurs within Lower montane coniferous forest (rocky, and serpentine), growing at elevations from 305 to 1500 meters. Streptanthus howellii is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Streptanthus howellii Wats.
Common Name:	Howell's jewelflower
Family:	Brassicaceae
Element Code:	PDBRA2G0N0
USDA Plants Symbol:	STHO
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial herb
Blooming Period: Jul-Aug	Jul-Aug
Elevation:	305-1500 (1000-4920)
General Habitats:	Lower montane coniferous forest
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G2G3
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	USFS_S
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	28
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	3
Fair (C)	2
Poor (D)	3
None (X)	0
Unknown (U)	20

Location


California Endemic: False
California Counties and Islands: Name (Code)
Del Norte (DNT)
Quads: Name (Quad Code)
Gasquet (4112378), High Divide (4112481), High Plateau Mtn. (4112388), Shelly Creek Ridge (4112387)

Threat List Data from the CNDDB


Threat List Total:	5
EOs with Threat Listed:	Total EOs	% of EOs
	13	46 %
Road/trail construction/maint.	9	32%
Mining	8	28%
Improper burning regime	4	14%
Other	2	7%
Wood cutting or brush clearing	1	3%

Notes



Threatened by mining. Candidate for state listing in OR. See Proceedings of the American Academy of Arts and Sciences 20:353 (1885) for original description.
Threats:

Taxonomy:

Selected References

Streptanthus howellii profile for potential Species of Conservation Concern evaluation (2018)

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 8 December 2025].