Oak/Acorn Identification

White Oak:

(Quercus alba)

Grows in either dry or moist situations, but not in wet ones. Height to 100 feet tall throughout the Midwest, with heavy, often nearly horizontal branches; wide-spreading.

Leaves:

With five to seven rounded lobes in two distinct forms: one has shallow, wide, rounded lobes; the other has long, narrower, fingerlike lobes with indentations nearly to midrib of leaf.

Bark:

Light gray; rough with long loose scales; becoming blocky on very old trees.

Acorns:

About 3/4-inch long with a cup covered by warty scales.

The Latin alba means “white.”


Post Oak:

(Quercus stellata)

Grows in dry and rocky upland woods, to 60 feet tall. Characteristics similar to white oak. Found in Illinois, Missouri, Iowa, and Indiana.

Leaves:

Usually with five lobes, two of which, above the middle of the leaf, are broad, forming a cross with the axis of the leaf. These and the top lobe are normally slightly indented.

Bark:

Light brown; divided by deep fissures and scaly ridges.

Acorns:

Small to 3/4-inch long, the cup covers onethird to one-half of the nut. The Latin Stellata means “star,” referring to the starlike tufts of hair on the surfaces of the leaf.


Bur Oak:

(Quercus macrocarpa)

Grows both on upland and lowland sites, but does best on rich, moist soils; to 120 feet tall. Found throughout the Midwest.

Leaves:

The largest of any native oak, to one foot long and very wide. Two different basic shapes exist: one widest above the middle, the upper portion shallowly lobed, the lower lobes longer. The other has a deeply lobed central section with indentations coming close to the central vein and a narrower upper part, but still wider than the lower lobes. Both forms are found on the same tree.

Bark:

Similar to white oak but darker and more vertically ridged.

Acorns:

The largest of all North American oaks, about surrounded by a deep cup, which is scaly and has especially fond of them. Macrocarpa is Greek for “big-fruited.”


Swamp White Oak:

(Quercus bicolor)

A medium-sized oak of moist bottomlands. Found throughout the Midwest.

Leaves:

Shiny, green above, downy-white below, with many shallow, evenly spaced lobes all along the egg-shaped leaf, which is widest near the middle of the leaf.

Bark:

Bark on the upper limbs and twigs peels off in papery scales; dark brown and deeply fissured on the main stem of old trees.

Acorns:

Usually carried in pairs, characteristically on a long stem 2 ½ inches long, the cup scaly and with fine, wooly hair.

Bicolor, Latin”two-colored,” referring to the leaves.

Chinkapin Oak:

(Quercus muehlenbergii)

(also known as chestnut oak; Steyermark: Q. prinoides). Grows both on dry, rocky uplands and moist bottomlands to 100 feet tall. Found throughout the Midwest.

Leaves:

Coarsely serrated (like saw teeth) along entire margin, either narrow or wide oblong, wider above the middle, ending in a pointed tooth (but no bristles).

Bark:

Ashy gray; rough and flaky

Acorns:

Small, to 3/4-inch long, dark chestnut colored, the cup usually with a short nut. Chinkapin is the name of a shrubby chestnut, Muehlenbergii (often misspelled) for the botanist 1753-1815.

Swamp Chestnut Oak:

(Quercus michauxii)

(also know as cow-oak or basket oak).

Restricted to moist soils in low, wet woods and along streams; to 100 feet tall.

Leaves:

Similar to chinkapin oak but the small serrations (lobes are rounded, not toothed. Only the tip of the leaf is pointed. Leaf is egg-shaped with the broadest part above the middle.

Bark:

Light gray or tan, irregularly furrowed or scaly.

Acorns:

Large, to 1 ½-inches long, the cup acorn is quite low in tannin, and thus called the leaf resembles that of a true chestnut (Castanea). Michauxii for the French naturalist Andre Michaux, collect plants, 1746-1802.

Overcup Oak:

(Quercus lyrata)

Leaves:

Lobed with irregular broad lobes of varying depths. Leaf is dark green and shiny above; light green and hairy beneath.

Bark:

Brownish-gray and rough; with large irregular plates or ridges.

Acorns:

Up to 1-inch in diameter; almost entirely enclosed in a deep, unfringed cup. Restricted to southern bottomlands and a few central localities in southern Missouri, Illinois, and Indiana.


Dwarf Chestnut Oak:

(Quercus prinoides)

(also know as dwarf chinkapin or scrub oak). Grows as a multi-stemmed shrub only a few feet tall or as a small tree Usually found in prairies and open areas in western Missouri.

Leaves:

Similar to those of chinkapin oak but smaller and usually with more blunt lobes. Leaf is green above, lightercolored and hairy beneath.

Bark:

Brownish-gray becoming rough or scaly on older wood.

Acorns:

About ½-inch in diameter with small, warty scales on cup. This is the shortest of the Missouri’s oaks, and it can produce abundant acorns although only 3 to 10 feet tall.

Chestnut Oak or Rock Chestnut:

(Quercus prinus or Quercus montana )

Chestnut oak is a medium-sized tree, growing to heights of 50 to 70 feet. It has a broad, dense crown, and a large trunk of up to 2 1/2 feet in diameter. Chestnut oak grows on dry, rocky, wooded slopes that are frequently nutrient poor. Chestnut oak is very fire-resistant and under most conditions is a slow growing tree. Like the other oaks, it reproduces from seed as well as stump sprouts. It produces large quantities of acorns almost every year and is an important food source for songbirds, ruffled grouse, wild turkey, mice, deer, and other mammals. The wood of chestnut oak is very hard – harder than that of white oak.

Leaves:

The leaves are alternate and simple, and broadly lance shaped. They are typically from 4 to 9 inches long and up to 4 inches broad. They are pointed at the tip, narrowing toward the base, and have shallowly incised (indented), rounded teeth at the edges. They are leathery, smooth, and dark yellow-green on the surface and paler and hairy underneath.

Bark:

Rock chestnut oak bark is dark brown and furrowed. The ridges in between the furrows are slightly rounded, and the inner bark of the tree is reddish.

Acorns:

The acorns occur singly or in pairs, are on a very short stalk and are up to 1 1/2 inches long. The acorn is chestnut brown and the cup is a reddish brown and covers less than half the length of the acorn.

Northern Red Oak:

(Quercus rubra)

Grows on upland slopes, on moist bottomlands which face north or east and thus stay cooler. The tree can reach 100 feet.

Leaves:

Up to eight inches long with pointed lobes (which are not divided again at their tips), segmented to the midrib. Middle and upper lobes point diagonally upward and have bristle-pointed teeth. Leaves are yellowish-green above.

Bark:

Dark brown to black; smooth on young trees, eventually wide, flat ridges separated by shallow fissures; on very old trees more narrowly ridged.

Acorns:

One-inch long, oblong in shape. The cup saucerlike, flat, covers about one-third of the nut, and has a fine-hairy fringe.

Rubra, Latin, “red.”

Shumard Oak:

(Quercus shumardii)

A large tree, frequently to 100 feet tall, but taller specimens are known. Prefers moist bottomlands, but does occur also on uplands.

Leaves:

To eight inches long, deeply lobed, the tops of the lobes again shallowly divided, each tip with a bristle. Characteristically, the central lobes are more or less at right angles to the leaf axil (rather than pointing diagonally upward). Upper leaf surface dark green.

Bark:

Very similar to northern red oak.

Acorns:

Two kinds exist:

1. egg-shaped, to one inch long, cup saucer-like, enclosing ¼ of nut (var. shumardii)

2. with a deeper, bowl-shaped cup, enclosing at least 1/3 of nut (var. schneckii).

Blackjack Oak :

(Quercus marilandica)

(also know as scrub oak). With few exceptions a gnarled, short  tree found on rocky hillsides in poor and acid soils. The lower branches hang downward.

Leaves:

Large, leathery, dark green and shiny above, wedgeshaped to triangular, spreading toward the top. The top mildly  lobed, each lobe carrying one bristle which may disappear with age.

Bark:

Black; very rough, broken into square or rectangular blocks when old.

Acorns:

Normally only ½ -inch in diameter with deep cup covering half the nut.

Marilandica is Latin for the state of Maryland.

Pin Oak:

(Quercus Palustris)

Under natural conditions a medium-size tree that grows 50- to 70-feet tall in moist valleys, along streams, ponds and swamps, but also sometimes on dry locations. The lower branches spread downward, covering a large area. Pin oak grows faster than other oak species and has become a much planted ornamental. Many specimens provide good fall coloration.

Leaves:

Medium size, four-to-six-inches long with five to seven lobes, which are deeply divided. The ends of the lobes have two to three small divisions, each bristle-tipped. Leaves are dark green and shiny.

Bark:

Grayish-brown, smooth for many years.

Acorns:

Rounded, ½-inch diameter, often striped with many dark lines, with a thin, saucer-shaped cup.

Palustris, Latin, “marshy.”

Northern Pin Oak:

(Quercus ellipsoidalis)

Similar to pin oak but the acorns are more elongated. Also called Hill’s Oak. Can be found throughout the Midwest.

Black Oak:

(Quercus velutina)

(also known as yellow-bark oak). A medium-sized oak to 70 feet tall with a wide distribution. Tolerates rocky, acidic soils but grows also on bottomlands. The inner bark is yellow, rich in tannin. Grows throughout the entire Midwest.

Leaves:

To 12-inches long, the upper half much wider than the lower. The bottom margin of the lowest lobe nearly straight; seven-to-nine inches wide, rather shallow lobes, their ends indented into smaller lobes, each bristle-tipped. Leaves dark green above, pale green below.

Bark:

Black, rough and deeply furrowed. The inner bark is bright orange or yellow and can be used to distinguish black oak from scarlet, northern red and Shumard oaks.

Acorns:

Sharply pointed, to 3/4-inch long, well rounded, the scaly cup with a ragged fringe covers half of the nut. Black oak is considered a reliable producer of acorns.

Velutina, Latin, “velvety,’ probably referring to tufts of hair on the underside of the leaves.

Scarlet Oak :

(Quercus coccinea)

A medium-sized tree, Scarlet oak is one of the most common oaks of the flat ridgetops of the Eastern Ozarks of Missouri but can also be found in Indiana, Kentucky, Wisconsin, and Illinois.

Leaves:

Seven to nine lobes with wide, nearly circular depressions between the lobes. Smooth and dark green above, paler underneath. The leaves turn a deep scarlet in the fall.

Bark:

Smooth and gray, becoming rough, nearly black, broken up into irregular ridges on old trees.

Acorns:

Up to one-inch in diameter, often with concentric rings around the tip. Between 1/3 to ½ of acorn is enclosed in a thin, bowl-shaped cup.

Southern Red Oak:

(Quercus falcata)

It is found on dry upland sites in southeast Missouri, in southern Illinois and in counties along the Arkansas border.

Leaves:

Up to nine inches long and found in two forms: 1) shallow 3-lobed; 2) 5 to 7 deep lobes, often sickle-shaped. The base of the leaf is rounded. Surfaces are dark green and shiny above; pale and hairy below.

Bark:

Similar to black oak except the inner bark is only slightly yellow.

Acorns:

Small, about ½-inch long; enclosed one-third or less in a thin, shallow cup. Restricted to counties along southern Missouri, southern Illinois and northern Arkansas.

Cherrybark Oak:

(Quercus falcata var. pagoda)

Cherrybark oak is limited to the bottomland forest of southern Missouri, Illinois, and Indiana. It is among the largest of the southern oaks.

Leaves:

Five to 11 irregular lobes, with the top of the lobes at nearly right angles to the midrib. Surface is dark green and shiny above, pale and hairy underneath.

Bark:

Nearly black; broken into shallow fissures. The tree was named cherrybark oak because of the resemblance of the bark of older trees to black cherry.

Acorn:

Similar to southern red oak.

Nutall Oak:

(Quercus texana)

Nutall oak is found on poorly drained clay bottomland sites. In Missouri it is known only from a few southeastern counties. Its leaves and bark are similar to pin oak, a tree it is easily confused with. Nutall oak may be distinguished from pin oak by its acorn. Nutall oak acorns are elongated, up to 1 1/4 inches long, one-fourth to one-half enclosed in a deep, thick cup.

Restricted to four southern Missouri counties.


Shingle Oak:

(Quercus imbricaria)

A large tree, grows to 100 feet, tolerating both dry or moist habitats throughout much of the Midwest. Said to be the longest-lived oak under cultivation when used for ornamental purposes.

Leaves:

Broadest above the middle, to two-inches wide, oblong-elliptical, with a shiny upper surface, to six-inches long; the only oak with large, entire leaves in Missouri.

Bark:

Smooth gray when young; becoming nearly black with broad ridges and shallow fissures.

Acorns:

Small, about ¾ inch long, but the nut nearly round, the cup with brown, hairy scales, enclosing one-third to one-half the nut. Shingle oak implies the former use for roof shingles; imbricaria is Latin for “overlapping,” like roof shingles. May refer to the acorn scales.

Willow Oak:

(Quercus phellos)

A medium-size oak, to 75 feet tall, growing on poorly drained soils and swampy woods. Restricted to southern parts of Midwestern states. May do well when planted as ornamental throughout the Midwest.

Leaves:

Narrow, lance-shaped, willowlike; much narrower than the similar shingle-oak leaves, light green above with a pointed tip.

Bark:

Smooth and gray on young trees; later becoming darker and breaking into thick rough ridges separated by irregular fissures.

Acorns:

Small, only ½ inch long, pale brownish-yellow, with striped nuts. The bitter nuts are important food for ducks.

Phellos, Greek, means “cork”.

Water Oak:

(Quercus nigra)

A medium-sized tree found in moist bottomland sites with exception of permanent swamps in southern Missouri.

Leaves:

Two to four inches long, broader at the tip than the base. Edges of the leaves are smooth or slightly wavy.

Bark:

Nearly black, with wide scaly ridges.

Acorns:

About ½-inch long, nearly black; with a thin, saucer-shaped cup. Restricted to four counties in and near the Missouri Bootheel.


Information Sourced From:

The MillionTree Project’s Oak/Acorn Identification Guide was adapted primarily from: The Missouri Department of Conservation

Additional information was also sourced from:

Illinois State Museum

The University of Wisconsin-Green Bay’s Cofrin Center for Biodiversity

The University of Kentucky

IPFW Indiana University-Purdue University Fort Wayne

TreeListByCommonName-Page1-Test.htm

Minnesota Department of Natural Resources

Iowa State University-University Extension