The white oak is one of three groups of oaks. Only the red oak and white oak are found in North America. White oaks have round-lobed leaves that lack spines or bristles. The acorns are sweet, have smooth inner shells, and ripen in one season. Chestnut oaks, a subsection of white oaks, have unlobed leaves with broadly toothed margins. White oaks are found throughout the eastern half of the United States. The trees can grow to 100 feet (30 m) in height and four feet (1.2 m) in diameter. The bark of the white oak is gray and broken into vertical columns of plates.