Taxon Details

Cirsium hydrophilum var. vaseyi

Mt. Tamalpais thistle

View Report Copy Link Calflora eFlora CCH CalPhotos iNaturalist

Taxon Summary:

Cirsium hydrophilum var. vaseyi, commonly known as Mt. Tamalpais thistle, is a perennial herb in the Asteraceae that is found only in California. It occurs within Broadleafed upland forest, Chaparral, and Meadows and seeps, growing at elevations from 240 to 620 meters. Cirsium hydrophilum var. vaseyi is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification

Scientific Name: Cirsium hydrophilum (Greene) Jeps. var. vaseyi (Gray) J.T. Howell
Common Name: Mt. Tamalpais thistle
Family:	Asteraceae
Element Code:	PDAST2E1G2
USDA Plants Symbol:	CIHYV
Synonyms/Other Names:
Name Status:	JEF, FNA, POWO, IPNI, Tropicos

Conservation Status

CA Rare Plant Rank:	1B.2
Fed List:	None
State List:	None
Global Rank:	G2T1
State Rank:	S1
Other Status:	SB_CalBG/RSABG
CRPR Changes:
Add Date:	1974-01-01
Date Edited:	2022-12-06

Ecology and Life History

Lifeform: perennial herb

Blooming Period: May-Aug

Elevation:
240 - 620 meters
785 - 2035 feet

General Habitats:

Broadleafed upland forest
Chaparral
Meadows and seeps

Microhabitat Details:

Microhabitat:

Seeps
Serpentine

Notes

Notes: Known from fewer than 20 occurrences on Mt. Tamalpais. Threatened by road construction and non-native plants. See Synoptical Flora of North America 1(2):403-404 (1884) for original description.
Threats:
Taxonomy:

Threat List Data from the CNDDB

THREAT LIST:
Threat List Total:	6
	Total EOs	% of EOs
EOs with Threat Listed:	9	64 %
Road/trail construction/maint.	5	35%
Foot traffic/trampling	3	21%
Non-native plant impacts	2	14%
Recreational use (non-ORV)	2	14%
Development	1	7%
Other	1	7%

Occurrence Data from the CNDDB

Element Occurrence Ranks:
Total Occurrences:					14
A	B	C	D	X	U
2	6	0	0	1	5

Occurrence Status:
Historical >20 Years	9
Recent <=20 Years	5

Presence:
Presumed Extant	13
Possibly Extirpated	0
Presumed Extirpated	1

Location

California Endemic:

California Island:

States: Name (Code)
California (CA)

California Counties and Islands: Name (Code)
Marin (MRN), San Francisco (SFO)

Quads: Name (Quad Code)
Bolinas (3712286), San Francisco North (3712274), San Geronimo (3812216), San Rafael (3712285)

Notes:

Definitions of codes following a county and/or quad:
*		Presumed extirpated
(?)		Occurrence confirmed, but possibly extirpated
Quad and county data is imported from the CNDDB. Species may be present in other areas where conditions are favorable. These data should NOT be substituted for pre-project review or for on-site surveys.

Regional Map

Map

Presumed Extant

Click on quad for name. Hold Shift Key to use mouse scroll wheel

CNPS Rare Plant Inventory