Leaves are alternate, simple, lobed. Lobes have pointed tips. Fruit is an acorn.
The black oak is a medium sized tree, 60 to 80 feet tall and one to two feet in diameter, with a wide and irregularly shaped crown. It is found widely over the eastern part of the United States as far west as eastern Nebraska, Kansas, Oklahoma and Texas. It is found quite generally throughout Iowa on dry ridges.
The leaves are single, 5 to 7 lobed, bristle-tipped, 5 to 10 inches long and 3 to 6 inches wide. The lobes are sometimes shallow and sometimes deeply lobed, the shape varying greatly. They are dark green and shiny above and pale beneath, with rusty brown hairs in the forks of the leaf veins.
The buds are distinctly angular. The twigs are stout and dull reddish brown to dark brown in color.
The black oak's small, rounded acorn is often hairy or velvety. The acorn cap reaches one-half way up the acorn with a rough margin.
On branches and young trees the bark is smooth and dark brown. It is thick and black on older trees, with deeply furrowed and broken ridges. The inner bark is bright yellow and bitter to the taste, because of the tannic acid it contains
This key was developed by "bt" in June 1982. It was put into HTML format by Stephen Ostermiller in July 1997. Copies of the entire guide in zip format that may be taken to camp on a laptop are available to those who write.