Taxon Report

Quercus cedrosensis C.H. Muller

Cedros Island oak

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Taxon Summary

Quercus cedrosensis, commonly known as Cedros Island oak, is a perennial evergreen tree in the Fagaceae that is found in California and elsewhere. It occurs within Chaparral, Closed-cone coniferous forest, and Coastal scrub, growing at elevations from 255 to 960 meters. Quercus cedrosensis is ranked 2B.2, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Quercus cedrosensis C.H. Muller
Common Name:	Cedros Island oak
Family:	Fagaceae
Element Code:	PDFAG05650
USDA Plants Symbol:	QUCE2
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial evergreen tree
Blooming Period: Apr-May	Apr-May
Elevation:	255-960 (835-3150)
General Habitats:	Chaparral, Closed-cone coniferous forest, Coastal scrub
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	2B.2
Global Rank:	G2G3
State Rank:	S1
State List:	None
Fed List:	None
Other Status:	IUCN_VU; SB_CRES; SB_SDBG
CRPR Changes:	changed from 2.2 to 2B.2 on 2013-06-12

Occurrence Data from the CNDDB


Total Occurrences:	9
Element Occurrence Ranks:
Excellent (A)	3
Good (B)	0
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	6

Location


California Endemic: False
California Counties and Islands: Name (Code)
San Diego (SDG)
Quads: Name (Quad Code)
Dulzura (3211667), Otay Mountain (3211657), San Vicente Reservoir (3211688), Tecate (3211656)

Threat List Data from the CNDDB


Threat List Total:	3
EOs with Threat Listed:	Total EOs	% of EOs
	3	33 %
Other	2	22%
Road/trail construction/maint.	2	22%
Improper burning regime	1	11%

Notes



Known in CA from fewer than ten occurrences near Otay Mtn. Possibly threatened by road construction and Border Patrol activities. Not in The Jepson Manual. See Madroño 16(6):188 (1962) for original description.
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 18 November 2025].