CNPS

CNPS Rare Plant Inventory

Species Details

Cirsium hydrophilum var. vaseyi

Mt. Tamalpais thistle

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  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:

  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
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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 Total: 6
Total EOs % of EOs
EOs with Threat Listed: 9 64 %
THREAT LIST:
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%

  Occurrence Data from the CNDDB

Total Occurrences: 14
Element Occurrence Ranks:
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

  Selected References

Suggested Citation:
California Native Plant Society, Rare Plant Program. 2024. Rare Plant Inventory (online edition, v9.5). Website https://www.rareplants.cnps.org [accessed 19 April 2024].