Taxon Report

Cirsium arizonicum (A. Gray) Petrak var. tenuisectum Keil

desert mountain thistle

Print Report

Taxon Summary

Cirsium arizonicum var. tenuisectum, commonly known as desert mountain thistle, is a perennial herb in the Asteraceae that is found in California and elsewhere. It occurs within Joshua tree "woodland", Mojavean desert scrub, and Pinyon and juniper woodland, growing at elevations from 1500 to 2800 meters. Cirsium arizonicum var. tenuisectum is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Cirsium arizonicum (A. Gray) Petrak var. tenuisectum Keil
Common Name:	desert mountain thistle
Family:	Asteraceae
Element Code:	PDAST2E083
USDA Plants Symbol:
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial herb
Blooming Period: Jun-Nov	Jun-Nov
Elevation:	1500-2800 (4920-9185)
General Habitats:	Joshua tree "woodland", Mojavean desert scrub, Pinyon and juniper woodland
Microhabitat:	Disturbed areas, Roadsides (often), Rocky
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G5T2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	SB_CalBG/RSABG
CRPR Changes:	added to 1B.2 on 2006-12-27

Occurrence Data from the CNDDB


Total Occurrences:	8
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	1
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	7

Location


California Endemic: False
California Counties and Islands: Name (Code)
San Bernardino (SBD)
Quads: Name (Quad Code)
Clark Mtn. (3511555), Ivanpah (3511533), Pinto Valley (3511523)

Threat List Data from the CNDDB


Threat List Total:	2
EOs with Threat Listed:	Total EOs	% of EOs
	2	25 %
Other	1	12%
Recreational use (non-ORV)	1	12%

Notes



Known in CA only from the New York Mountains of San Bernardino County. The name Cirsium nidulum has long been misapplied to this species. May be distinctive enough to be its own taxon and not a variety of Cirsium arizonicum. See SIDA 21(1): 210 (2004) for original description.
Threats:

Taxonomy:

Selected References

CRPR List Addition on 2006-12-27

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 January 2025].