Quercus douglasii
| Blue oak | |
|---|---|
| A large blue oak in a pasture in Mariposa County, California | |
| Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Fagales |
| Family: | Fagaceae |
| Genus: | Quercus |
| Subgenus: | Quercus subg. Quercus |
| Section: | Quercus sect. Quercus |
| Species: | Q. douglasii |
| Binomial name | |
| Quercus douglasii | |
| Natural range | |
| Synonyms | |
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Quercus douglasii, known as blue oak, is a species of oak endemic to California, common in the Coast Ranges and the foothills of the Sierra Nevada. It is California's most drought-tolerant deciduous oak, and is a dominant species in the blue oak woodland ecosystem. It is occasionally known as mountain oak and iron oak.