valley oak Fagaceae Quercus
Leaf: Alternate, simple, and deciduous; 2 to 4 inches long; margins typically have 9 to 11 deep, rounded lobes; dull green and often pubescent above, and pale green below.
Flower: Species is monoecious; males flowers are borne in pendent yellow-green catkins (aments) about 1 to 2 inches long; female flowers are small, usually solitary or in clusters of 2 or 3, and occur in the axils of leaves on current year's twigs; appearing in spring.
Fruit: Acorns; shape varies greatly but is usually conical or bullet-shaped; 1 to 2 inches long; caps may be shallow or deep and often have warty knobs; ripen in a single year.
Twig: Slender; gray-brown to brown; pubescent when young but smooth by second year; often bear the spherical galls of native wasps.
Bark: Younger bark is thin (up to 1 inch), gray, and checkered or shallowly fissured; older bark is darker gray, several inches thick, and deeply fissured with flattened ridges.
Form: A large deciduous tree with massive limbs and a rounded, spreading crown; terminal branches often droop to the ground.
Looks like: Oregon white oak - blue oak