The California Scrub Oak (Quercus berberidifolia) is a small evergreen or semi-evergreen shrubby oak in the white oak section Quercus sect. Quercus. It grows to 1-2 m tall, rarely to 4 m, and has sharply toothed, dull green leaves which are 1.5-3 cm long and 1-2 cm broad, leathery on their top surfaces and somewhat hairy underneath. The solitary or paired brown acorns are 1-3 cm long and 1-2 cm broad, and pointed or egg-shaped with thin caps when mature; they mature in about 6-8 months after pollination.
It is a native of the scrubby hills of California. It is a common member of chaparral ecosystems; in fact, the word chaparral is derived from the Spanish word for scrub oak, chaparro. Many other scrub-type oaks can be found in the region, and careful inspection is required to identify individuals of Q. berberidifolia and its hybrids. In cooler, more exposed areas, scrub oak is usually a small, compact shrub, but in warm or sheltered areas the plant can spread out and grow several meters high.
Q. berberidifolia sometimes hybridizes with other species.
It is often known simply as scrub oak, though this name is also applied to other Quercus species, especially several which were formerly grouped under the single name Q. dumosa and are found in scrubby habitats.