Taxon Report

Cirsium occidentale (Nutt.) Jeps. var. lucianum D.J. Keil

Cuesta Ridge thistle

Print Report

Taxon Summary

Cirsium occidentale var. lucianum, commonly known as Cuesta Ridge thistle, is a perennial herb in the Asteraceae that is found only in California. It occurs within Chaparral, growing at elevations from 500 to 750 meters. Cirsium occidentale var. lucianum is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Cirsium occidentale (Nutt.) Jeps. var. lucianum D.J. Keil
Common Name:	Cuesta Ridge thistle
Family:	Asteraceae
Element Code:	PDAST2E1Z6
USDA Plants Symbol:
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial herb
Blooming Period: Apr-Jun	Apr-Jun
Elevation:	500-750 (1640-2460)
General Habitats:	Chaparral
Microhabitat:	Disturbed areas, Roadsides, Rocky (often), Serpentine, Slopes (often)
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G3G4T2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	BLM_S
CRPR Changes:	added to 1B.2 on 2011-04-08

Occurrence Data from the CNDDB


Total Occurrences:	9
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	0
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	9

Location


California Endemic: True
California Counties and Islands: Name (Code)
San Luis Obispo (SLO)
Quads: Name (Quad Code)
Atascadero (3512046), Lopez Mtn. (3512035), Morro Bay North (3512047), San Luis Obispo (3512036), Santa Margarita Lake (3512034)

Threat List Data from the CNDDB


Threat List Total:	5
EOs with Threat Listed:	Total EOs	% of EOs
	2	22 %
Improper burning regime	2	22%
ORV activity	1	11%
Recreational use (non-ORV)	1	11%
Road/trail construction/maint.	1	11%
Vandalism/dumping/litter	1	11%

Notes



Known only from fewer than 10 extant occurrences in the southern Santa Lucia Mtns. Of SLO Co. Possibly threatened by fire suppression. Similar to var. californicum. Not in The Jepson Manual (1993). See Sida 21(1):207-219 (2004) for original description.
Threats:

Taxonomy:

Selected References

CRPR List Addition on 2011-04-08

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 27 October 2025].