Species Details

Ceanothus masonii

Mason's ceanothus

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Species Description:

Ceanothus masonii, commonly known as Mason's ceanothus, is a perennial evergreen shrub in the Rhamnaceae that is found only in California. It occurs within Chaparral (openings, rocky, and serpentinite), growing at elevations from 230 to 500 meters. Ceanothus masonii is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification

Scientific Name: Ceanothus masonii McMinn
Common Name: Mason's ceanothus
Family:	Rhamnaceae
Element Code:	PDRHA04200
USDA Plants Symbol:	CEMA3
Synonyms/Other Names:
Name Status:	JEP, FNA, POWO, IPNI, Tropicos

Conservation Status

CA Rare Plant Rank:	1B.2
Fed List:	None
State List:	CR (1978-11-01)
Global Rank:	G1
State Rank:	S1
Other Status:	SB_CalBG/RSABG; SB_USDA
CRPR Changes:
Add Date:	1974-01-01
Date Edited:	2021-05-26

Ecology and Life History

Lifeform: perennial evergreen shrub

Blooming Period: Mar-Apr

Elevation:
230 - 500 meters
755 - 1640 feet

General Habitats:

Chaparral (openings, rocky, serpentinite)

Microhabitat Details:

Microhabitat:

Notes

Notes: Known from approximately five occurrences. Threatened by fire suppression. May be a variety of C. gloriosus; needs further study. See Madroño 6(5):171-173 (1942) for original description.
Threats:
Taxonomy:

Threat List Data from the CNDDB

THREAT LIST:
Threat List Total:	4
	Total EOs	% of EOs
EOs with Threat Listed:	5	63 %
Grazing	2	25%
Improper burning regime	2	25%
Road/trail construction/maint.	2	25%
Other	1	12%

Occurrence Data from the CNDDB

Element Occurrence Ranks:
Total Occurrences:					8
A	B	C	D	X	U
1	2	1	0	0	4

Occurrence Status:
Historical >20 Years	5
Recent <=20 Years	3

Presence:
Presumed Extant	8
Possibly Extirpated	0
Presumed Extirpated	0

Location

California Endemic:

California Island:

States: Name (Code)
California (CA)

California Counties and Islands: Name (Code)
Marin (MRN)

Quads: Name (Quad Code)
Bolinas (3712286), Petaluma (3812226), Point Reyes NE (3812227)

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 Rare Plant Inventory