Quercus kelloggii
California black oak, California Black Oak
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Family: Fagaceae · Type: Shrub / Tree · Native
Quercus kelloggii (California black oak) is a native California shrub / tree in the Fagaceae family, recognized by large bristle-tipped lobed leaves and dark bark highly distinctive.
California black oak is a native tree found in California floristic province (except Great Valley, Southern California Coast, and Channel Islands) and Modoc Plateau in woodland and conifer forest slopes and valleys at elevations of 30 to 2,660 meters. Flowering from mid-February to May, this tree produces small greenish-yellow flowers in clusters. Growing to 35 meters tall with a deciduous habit, it develops a distinctive trunk with deeply furrowed, checkered bark that ranges from dark gray to black. Its large leaves are widely elliptic or nearly round, 6 to 20 centimeters long, with bright green upper surfaces and pale green undersides featuring 6 lobed margins with 1 to 4 bristle-tipped teeth. The tree produces acorns with cup-shaped shells 16 to 25 millimeters wide, maturing in its second year.
Identification and appearance
Key characters: 35 sympatric species; large bristle-tipped lobed leaves and dark bark highly distinctive
Habitat and range
Habitat: Slopes, valleys, woodland, conifer forest
Elevation: 30-2660 m
California counties: Los Angeles, Kern, Glenn, Napa, Trinity, San Bernardino, Lake, Riverside, El Dorado, San Diego, San Mateo, Siskiyou, Mendocino, Monterey, San Luis Obispo, Marin, Shasta, Sonoma, Lassen, Solano, Amador, Fresno, Nevada, Placer, Inyo, Santa Cruz, Santa Clara, Mariposa, Tehama, Tulare, Modoc, Tuolumne, Madera, Contra Costa, Butte, Santa Barbara, Humboldt, Sierra, Plumas, Calaveras, Ventura, Del Norte, Orange, Sacramento, Yuba, San Joaquin, Alameda, Colusa, San Benito, San Francisco
Outside California: Oregon, Baja California
Bloom period
Quercus kelloggii blooms Mid Feb-May.
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 kelloggii native to California?
Yes. Quercus kelloggii is native to California (recorded as native).
When does Quercus kelloggii bloom?
Quercus kelloggii blooms Mid Feb-May.
Where in California does Quercus kelloggii grow?
Quercus kelloggii occurs in Los Angeles, Kern, Glenn, Napa, Trinity, San Bernardino, Lake, Riverside and other counties, at elevations of 30-2660 m.
What plant family does Quercus kelloggii belong to?
Quercus kelloggii is in the Fagaceae family, genus Quercus.
What habitat does Quercus kelloggii grow in?
Quercus kelloggii grows in Slopes, valleys, woodland, conifer forest.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
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.