CNPS

CNPS Rare Plant Inventory

Species Details

Ceanothus thyrsiflorus var. obispoensis

San Luis Obispo ceanothus

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  Classification

Scientific Name:
Ceanothus thyrsiflorus Eschsch. var. obispoensis D. O. Burge
Common Name:
San Luis Obispo ceanothus
Family: Rhamnaceae
Element Code: PDRHA04461
USDA Plants Symbol:
Synonyms/Other Names:

  Conservation Status

CA Rare Plant Rank: 1B.1
Fed List: None
State List: None
Global Rank: G5T1
State Rank:
 S1
Other Status: SB_UCSC
CRPR Changes:
added to 1B.1 on 2019-01-30
Add Date: 2019-01-30
Date Edited: 2023-08-01

  Ecology and Life History

Lifeform: perennial shrub
Blooming Period: Jun
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Elevation:
140 - 225 meters
460 - 740 feet
General Habitats:
  • Chaparral
  • Cismontane woodland
Microhabitat Details: Dacite
Microhabitat:

  Notes

Notes:
Similar to C. thyrsiflorus var. griseus; differentiated by dense, wavy, matted hairs on abaxial surfaces of young leaves and twigs, often forming a tomentum that obscures tertiary leaf venation.
Threats:
Potentially threatened by urbanization.
Taxonomy:

  Threat List Data from the CNDDB

Threat List Total: 0
Total EOs % of EOs
EOs with Threat Listed: 0 %
THREAT LIST:
No threats

  Occurrence Data from the CNDDB

Total Occurrences: 3
Element Occurrence Ranks:
A B C D X U
0 0 0 0 0 3
Occurrence Status:
Historical >20 Years 0
Recent <=20 Years 3
Presence:
Presumed Extant 3
Possibly Extirpated 0
Presumed Extirpated 0

  Location

California Endemic:
California Island:
States: Name (Code)
California (CA)
California Counties and Islands: Name (Code)
San Luis Obispo (SLO)
Quads: Name (Quad Code)
Morro Bay South (3512037)
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

CNPS Status Review: Proposed Addition to CRPR 1B.1 G5T1/ S1 (2019)
Original Description: Systematic Botany 42(3):529-542 (2017)
Suggested Citation:
California Native Plant Society, Rare Plant Program. 2024. Rare Plant Inventory (online edition, v9.5). Website https://www.rareplants.cnps.org [accessed 25 April 2024].