Taxon Report

Streptanthus glandulosus Hook. ssp. niger (Greene) Al-Shehbaz et al.

Tiburon jewelflower

Print Report

Taxon Summary

Streptanthus glandulosus ssp. niger, commonly known as Tiburon jewelflower, is a annual herb in the Brassicaceae that is found only in California. It occurs within Valley and foothill grassland, growing at elevations from 30 to 150 meters. Streptanthus glandulosus ssp. niger is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Streptanthus glandulosus Hook. ssp. niger (Greene) Al-Shehbaz et al.
Common Name:	Tiburon jewelflower
Family:	Brassicaceae
Element Code:	PDBRA2G0T0
USDA Plants Symbol:
Synonyms/Other Names:	Streptanthus niger

Ecology and Life History


Lifeform:	annual herb
Blooming Period: May-Jun	May-Jun
Elevation:	30-150 (100-490)
General Habitats:	Valley and foothill grassland
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G4T1
State Rank:	S1
State List:	CE
Fed List:	FE
Other Status:	SB_CalBG/RSABG; SB_UCBG
CRPR Changes:

Occurrence Data from the CNDDB


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

Location


California Endemic: True
California Counties and Islands: Name (Code)
Marin (MRN)
Quads: Name (Quad Code)
San Quentin (3712284)

Threat List Data from the CNDDB


Threat List Total:	7
EOs with Threat Listed:	Total EOs	% of EOs
	2	100 %
Development	2	100%
Erosion/runoff	2	100%
Foot traffic/trampling	2	100%
Non-native plant impacts	2	100%
Other	2	100%
Road/trail construction/maint.	2	100%
Recreational use (non-ORV)	1	50%

Notes



Known from only two occurrences on the Tiburon Peninsula. Threatened by road construction, trampling, foot traffic, non-native plants, and development. See Bulletin of the Torrey Botanical Club 13:141 (1886) for original description, Madroño 14(7):217-227 (1958) for taxonomic treatment, and Systematic Botany 19(4):557-574 (1994) for discussion of S. glandulosus complex.
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 25 October 2025].