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white oak

white oak (Quercus alba)

Features and Behaviors

The deciduous white oak, Illinois’ state tree, may grow to a height of 100 feet and a trunk diameter of three feet. Its bark is gray or almost white with gray patches and has shallow furrows. The simple leaves are arranged alternately along the stem. Each leaf has seven to nine rounded lobes. The upper leaf surface is green and smooth while the lower surface is paler and smooth. A leaf may grow to 10 inches long and about five inches wide. Leaves turn red in the fall. Male and female flowers are separate but located on the same tree. The tiny flowers do not have petals. Male (staminate) flowers are arranged in drooping, yellow catkins, while the red female (pistillate) flowers are in small groups. The fruit is an acorn that may be found singly or in pairs on the stem. The acorn is oblong, up to three-fourths inch long, green to green-brown and shiny. The yellow-brown cup covers one-fourth of the acorn.

The white oak may be found statewide in Illinois. This tree grows in moist woods, on wooded slopes and in dry woods. The white oak flowers in April and May as its leaves begin to unfold. The heavy, strong wood is used in interior finishing, for making cabinets, for general construction, for fence posts and for fuel.

Illinois Range


​Kingdom: Plantae

Division: Magnoliophyta

Class: Magnoliopsida

Order: Fagales

Family: Fagaceae

Illinois Status: common, native