Taxon Report

Arctostaphylos auriculata Eastw.

Mt. Diablo manzanita

Print Report

Taxon Summary

Arctostaphylos auriculata, commonly known as Mt. Diablo manzanita, is a perennial evergreen shrub in the Ericaceae that is found only in California. It occurs within Chaparral (sandstone), and Cismontane woodland, growing at elevations from 135 to 650 meters. Arctostaphylos auriculata is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.

Classification


Scientific Name:	Arctostaphylos auriculata Eastw.
Common Name:	Mt. Diablo manzanita
Family:	Ericaceae
Element Code:	PDERI04040
USDA Plants Symbol:	ARAU
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial evergreen shrub
Blooming Period: Jan-Mar	Jan-Mar
Elevation:	135-650 (445-2135)
General Habitats:	Chaparral, Cismontane woodland
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.3
Global Rank:	G2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	SB_UCSC
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	17
Element Occurrence Ranks:
Excellent (A)	2
Good (B)	5
Fair (C)	5
Poor (D)	0
None (X)	0
Unknown (U)	5

Location


California Endemic: True
California Counties and Islands: Name (Code)
Contra Costa (CCA)
Quads: Name (Quad Code)
Antioch South (3712187), Clayton (3712188), Diablo (3712178), Tassajara (3712177)

Threat List Data from the CNDDB


Threat List Total:	10
EOs with Threat Listed:	Total EOs	% of EOs
	10	59 %
Improper burning regime	6	35%
Recreational use (non-ORV)	6	35%
Road/trail construction/maint.	6	35%
Grazing	5	29%
Other	4	23%
Development	2	11%
Biocides	1	5%
ORV activity	1	5%
Vandalism/dumping/litter	1	5%
Wood cutting or brush clearing	1	5%

Notes



Known from fewer than twenty occurrences. Threatened by road maintenance. See Bulletin of the Torrey Botanical Club 32:202 (1905) for original description, and American Midland Naturalist 23:622 (1940) for taxonomic treatment.
Threats:

Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 10 March 2025].