Taxon Details

Ceanothus thyrsiflorus var. obispoensis

San Luis Obispo ceanothus

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Taxon Summary:

Ceanothus thyrsiflorus var. obispoensis, commonly known as San Luis Obispo ceanothus, is a perennial shrub in the Rhamnaceae that is found only in California. It occurs within Chaparral, and Cismontane woodland, growing at elevations from 140 to 225 meters. Ceanothus thyrsiflorus var. obispoensis is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

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:
Name Status:	JEF, FNA, POWO, IPNI, Tropicos

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

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:
Threat List Total:	0
	Total EOs	% of EOs
EOs with Threat Listed:	0	%

Occurrence Data from the CNDDB

Element Occurrence Ranks:
Total Occurrences:					3
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

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CNPS Status Review:	Proposed Addition to CRPR 1B.1 G5T1/ S1 (2019)
Original Description:	Systematic Botany 42(3):529-542 (2017)

CNPS Rare Plant Inventory