Taxon Report

Arctostaphylos stanfordiana Parry ssp. decumbens Wells

Rincon Ridge manzanita

Print Report

Taxon Summary

Arctostaphylos stanfordiana ssp. decumbens, commonly known as Rincon Ridge manzanita, is a perennial evergreen shrub in the Ericaceae that is found only in California. It occurs within Chaparral (rhyolitic), and Cismontane woodland, growing at elevations from 75 to 370 meters. Arctostaphylos stanfordiana ssp. decumbens is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Arctostaphylos stanfordiana Parry ssp. decumbens Wells
Common Name:	Rincon Ridge manzanita
Family:	Ericaceae
Element Code:	PDERI041G4
USDA Plants Symbol:	ARSTD4
Synonyms/Other Names:	Arctostaphylos stanfordiana Parry var. repens Roof

Ecology and Life History


Lifeform:	perennial evergreen shrub
Blooming Period: Feb-Apr(May)	Feb-Apr(May)
Elevation:	75-370 (245-1215)
General Habitats:	Chaparral, Cismontane woodland
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G3T1
State Rank:	S1
State List:	None
Fed List:	None
Other Status:	SB_UCSC
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	12
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	2
Fair (C)	2
Poor (D)	1
None (X)	1
Unknown (U)	6

Location


California Endemic: True
California Counties and Islands: Name (Code)
Napa (NAP), Sonoma (SON)
Quads: Name (Quad Code)
Calistoga (3812255), Camp Meeker (3812248), Cazadero (3812351), Geyserville (3812268), Kenwood (3812245), Rutherford (3812244), Santa Rosa (3812246), Sebastopol (3812247)

Threat List Data from the CNDDB


Threat List Total:	9
EOs with Threat Listed:	Total EOs	% of EOs
	8	67 %
Development	7	58%
Agriculture	4	33%
Road/trail construction/maint.	3	25%
ORV activity	3	25%
Other	1	8%
Mining	1	8%
Non-native plant impacts	1	8%
Vandalism/dumping/litter	1	8%
Wood cutting or brush clearing	1	8%

Notes



Known from approximately ten occurrences. Seriously threatened by development, road construction, vehicles, and viticulture. See Four Seasons 4(2):16 (1972) for original description and 9(2):60-63 (1992) for revised nomenclature.
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 5 February 2025].