Quercus cedrosensis
Cedros island oak, Cedros Island Oak
(c) Sula Vanderplank, some rights reserved (CC BY) · licence
Family: Fagaceae · Type: Tree · Native
Conservation status: CNPS 2B.2
Quercus cedrosensis (Cedros island oak) is a native California tree in the Fagaceae family.
Cedros island oak is a rare (CNPS 2B.2) California native shrub found in the southwestern Peninsula Ranges on Otay Mountain in San Diego County in chaparral at elevations of 100 to 1,800 meters. Flowering from April to May, this plant produces flowers in muted tones within its evergreen canopy. Growing as a variable shrub from decumbent forms to 3 meters tall or prostrate forms to 20 centimeters, it features distinctive brown, hairy twigs that turn dark gray with age. Its leaves are small and variable, ranging from 0.6 to 2 centimeters long, with lanceolate to ovate blades that are glossy green on top and glaucous underneath, often with subtle spine-tipped irregular teeth. The fruit develops as a narrow ovoid nut nestled in a cup-shaped structure, maturing over two years with a tomentose interior shell.
Identification and appearance
Key characters: 0 sympatric species; geographically isolated
Habitat and range
Habitat: Chaparral
Elevation: 100-1800 m
Outside California: Baja California
Bloom period
Quercus cedrosensis blooms Apr-May.
Conservation status
CNPS 2B.2
How to tell it apart
vs Prunus: Quercus has acorns in cups; cherries/plums have fleshy round fruits.; vs Notholithocarpus: Quercus has drooping catkins; tanoak has upright flower spikes.; vs Rhamnus: Quercus has acorns; buckthorns have berry-like fruits.; vs Ceanothus: Quercus has acorns; California lilacs have small capsule fruits.; vs Platanus: Quercus has acorns; sycamores have hanging ball-shaped seed clusters.
Frequently asked questions
Is Quercus cedrosensis native to California?
Yes. Quercus cedrosensis is native to California (recorded as native).
When does Quercus cedrosensis bloom?
Quercus cedrosensis blooms Apr-May.
What plant family does Quercus cedrosensis belong to?
Quercus cedrosensis is in the Fagaceae family, genus Quercus.
Is Quercus cedrosensis rare or endangered?
Quercus cedrosensis carries California Rare Plant Rank 2B.2, state rank S1.
What habitat does Quercus cedrosensis grow in?
Quercus cedrosensis grows in Chaparral.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.