Quercus ×macdonaldii
Macdonald oak, Macdonald Oak
(c) Douglas Goldman, some rights reserved (CC BY-SA), uploaded by Douglas Goldman · licence
Family: Fagaceae · Type: Tree · Native
Quercus ×macdonaldii (Macdonald oak) is a native California tree in the Fagaceae family, recognized by lobed leaves distinctive for Channel Islands habitat.
Macdonald oak is a California native tree found on Santa Cruz, Santa Rosa, and Santa Catalina islands in woodland and canyon slopes at elevations below 600 meters. Flowering from March to May, this tree produces small greenish flowers typical of oak species. Growing 5 to 15 meters tall with a deciduous habit and scaly gray bark, it develops gnarled, spreading branches with tomentose (woolly) twigs. Its oblong to obovate leaves are 4 to 7 centimeters long, with 2 to 6 shallow pointed lobes, appearing glossy green on top and pale green underneath with dense stellate hairs. The tree produces acorn cups 10 to 20 millimeters wide with tubercled, grayish scales, maturing its nuts within one year.
Identification and appearance
Key characters: 15 sympatric species; lobed leaves distinctive for Channel Islands habitat
Habitat and range
Habitat: Slopes, canyons, woodland
Elevation: < 600 m
Bloom period
Quercus ×macdonaldii blooms Mar-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 ×macdonaldii native to California?
Yes. Quercus ×macdonaldii is native to California (recorded as native).
When does Quercus ×macdonaldii bloom?
Quercus ×macdonaldii blooms Mar-May.
What plant family does Quercus ×macdonaldii belong to?
Quercus ×macdonaldii is in the Fagaceae family, genus Quercus.
What habitat does Quercus ×macdonaldii grow in?
Quercus ×macdonaldii grows in Slopes, canyons, woodland.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.