Quercus cornelius-mulleri
Muller's oak, Muller's Oak
Photo by Chez Brungraber
Family: Fagaceae · Type: Tree · Native
Quercus cornelius-mulleri (Muller's oak) is a native California tree in the Fagaceae family, recognized by distinctive white tomentose undersides with yellow midrib.
Muller's oak is a California native shrub found in southern Sierra Nevada, San Gabriel Mountains (northern slope), San Bernardino Mountains (northern slope), Peninsular Ranges (eastern slope), southern desert mountains including Little San Bernardino Mountains, and desert regions at elevations of 300 to 2,140 meters in chaparral and pinyon woodland. Flowering from February to April, this shrub produces small cream or yellow flowers on densely branched evergreen stems. Growing 1 to 2.5 meters tall with finely tomentose twigs, it forms a compact, intricate branching structure. Its leathery leaves are oblong to narrowly obovate, 2.5 to 3.5 centimeters long, with yellow to gray-green surfaces and densely white-tomentose undersides, featuring entire or subtly toothed margins. The mature acorns develop in cup-shaped husks 12 to 20 millimeters wide, with elliptical nuts 20 to 30 millimeters long.
Identification and appearance
Key characters: 23 sympatric species; distinctive white tomentose undersides with yellow midrib
Habitat and range
Habitat: Slopes, generally granitic soils, chaparral, pinyon woodland
Elevation: 300-2140 m
California counties: San Bernardino, Riverside, San Diego, Orange, Imperial, Kern, Los Angeles, Marin, Ventura
Outside California: Baja California
Bloom period
Quercus cornelius-mulleri blooms Feb-Apr.
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 cornelius-mulleri native to California?
Yes. Quercus cornelius-mulleri is native to California (recorded as native).
When does Quercus cornelius-mulleri bloom?
Quercus cornelius-mulleri blooms Feb-Apr.
Where in California does Quercus cornelius-mulleri grow?
Quercus cornelius-mulleri occurs in San Bernardino, Riverside, San Diego, Orange, Imperial, Kern, Los Angeles, Marin and other counties, at elevations of 300-2140 m.
What plant family does Quercus cornelius-mulleri belong to?
Quercus cornelius-mulleri is in the Fagaceae family, genus Quercus.
What habitat does Quercus cornelius-mulleri grow in?
Quercus cornelius-mulleri grows in Slopes, generally granitic soils, chaparral, pinyon woodland.
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.