Red oak, gray oak

This tree usually grows 18 to 25 m tall, but may reach over 35 m. Its bark is smooth and gray when young, but develops dark wide grooves and long flat ridges with age. The twigs are moderately stout, smooth and dark red or greenish-brown. The terminal buds are reddish-brown, pointed, shiny and smooth. The alternate, simple leaves are 10 to 20 cm long. They have 7 to 13 divided lobes, ending in a spiny tip. Their V-shaped notches reach halfway to the central vein. The leaves are dull or shiny yellowish-green. The flowers are tiny. The male flowers are grouped in drooping, flexible, spindly catkins; the female flowers are single or in small groups on a sturdy stalk. The fruit is a reddish-brown acorn with a bitter seed. It is ovoid, 1.5 to 2.8 cm long and bears a usually shallow saucer-shaped cup that encloses about one-quarter to one-third of the nut.