The seed or fruit of an oak.

Acorn

The seed or fruit of an oak.

This shows the acorn of Bear Oak, Quercus ilicifolia, (Keeler, 1915).

Bear Oak Acorn

This shows the acorn of Bear Oak, Quercus ilicifolia, (Keeler, 1915).

This shows the acorn of Black Jack Oak, Quercus marilandica, (Keeler, 1915).

Black Jack Oak Acorn

This shows the acorn of Black Jack Oak, Quercus marilandica, (Keeler, 1915).

This shows the acorn of Black Oak, Quercus velutina, (Keeler, 1915).

Black Oak Acorn

This shows the acorn of Black Oak, Quercus velutina, (Keeler, 1915).

This shows the acorn of Bur Oak, Quercus macrocarpa, (Keeler, 1915).

Bur Oak Acorn

This shows the acorn of Bur Oak, Quercus macrocarpa, (Keeler, 1915).

This shows the acorn of chestnut Oak, Quercus prinus, (Keeler, 1915).

Chestnut Oak Acorn

This shows the acorn of chestnut Oak, Quercus prinus, (Keeler, 1915).

This shows the acorn of Chinquapin Oak, Quercus prinoides, (Keeler, 1915).

Chinquapin Oak Acorn

This shows the acorn of Chinquapin Oak, Quercus prinoides, (Keeler, 1915).

This shows the acorn of Pin Oak, Quercus palustris, (Keeler, 1915).

Pin Oak Acorn

This shows the acorn of Pin Oak, Quercus palustris, (Keeler, 1915).

This shows the acorn of Post Oak, Quercus minor, (Keeler, 1915).

Post Oak Acorn

This shows the acorn of Post Oak, Quercus minor, (Keeler, 1915).

This shows the acorn of Red Oak, Quercus rubra, (Keeler, 1915).

Red Oak Acorn

This shows the acorn of Red Oak, Quercus rubra, (Keeler, 1915).

This shows the acorn of Scarlet Oak, Quercus coccinea, (Keeler, 1915).

Scarlet Oak Acorn

This shows the acorn of Scarlet Oak, Quercus coccinea, (Keeler, 1915).

This shows the acorn of Shingle Oak, Quercus imbricaria, (Keeler, 1915).

Shingle Oak Acorn

This shows the acorn of Shingle Oak, Quercus imbricaria, (Keeler, 1915).

This shows acorns of Spanish Oak, Quercus digitata, (Keeler, 1915).

Spanish Oak Acorn

This shows acorns of Spanish Oak, Quercus digitata, (Keeler, 1915).

This shows the acorn of Swamp White Oak, Quercus platanoides, (Keeler, 1915).

Swamp Oak Acorn

This shows the acorn of Swamp White Oak, Quercus platanoides, (Keeler, 1915).

This shows the acorn of Willow Oak, Quercus phellos, (Keeler, 1915).

Willow Oak Acorn

This shows the acorn of Willow Oak, Quercus phellos, (Keeler, 1915).

This shows the acorn of Yellow Oak, Quercus acuminata, (Keeler, 1915).

Yellow Oak Acorn

This shows the acorn of Yellow Oak, Quercus acuminata, (Keeler, 1915).

Leaves - simple; alternate; edge slightly lobed at the upper part (edge of the lobes entire). Outline - abruptly widening above. Apex - of lobes, rounded or sometimes slightly pointed, and bristle-tipped, at least until old. Base - heart-shape or rounded. Leaf - three to four inches long (on vigorous shoots much longer); dark green, smooth, and shining above; below rusty and roughish, thick and tough; ribs distinct above. Lobes - three (sometimes five), very short, and above the middle of the leaf. Bark - of tree, rough and blackish. Acorn - nearly or quite stemless. Cup - top-shaped, coarsely scaly. Nut - one half to two thirds of an inch long; rounded egg-shape; darkish brown when ripe; nearly one half covered by the cup. October. Found - on Long Island, southward and westward. Very common through the Southern States. General Information - A small tree, eight to twenty-five feet high; of slight value except for fuel. Quercus, possible from a Celtic word meaning to inquire, because it was among the oaks that the Druids oftenest practised their rites.

Genus Quercus, L. (Oak)

Leaves - simple; alternate; edge slightly lobed at the upper part (edge of the lobes entire). Outline…

The leaf of a Black oak tree.

Black Oak Leaf

The leaf of a Black oak tree.

Leaves - simple; alternate; edge lobed (edge of the lobes mostly entire, but oftenest with a few teeth toward the end). Outline - reverse egg-shape or oval. Base - usually rounded. Ends of the lobes and of the few teeth, sharp and bristle-pointed, especially when young. Leaf - five to eight inches long; three to five inches wide; very variable. The two types, a and b, are often found on the same tree; b is a variation toward the leaf of the Scarlet Oak. The upper surface is roughish, becoming smoother when mature; the undersurface, rusty-downy until mid-summer, when the down mostly disappears, except from the angles of the ribs. Bark - of trunk, blackish and deeply and roughly furrowed, with an inner bark that is very thick and yellow and bitter. Acorns - variable; usually small; on short stems. Cups - thick; somewhat top-shaped; scales distinct and rather large. . Nut - one half to two thirds of an inch long; rounded; nearly one third covered by the cup. Kernel, bright yellow or orange and bitter. October. Found - from Southern Maine southward and westward. Very common, especially in the Atlantic forests. General Information - A tree fifty to a hundred feet high, with wood that is inferior to that of the White Oak. The yellow inner bark (quercitron of the shops) is a valuable dye, and is rich in tannin. Late in the autumn the leaves turn to a rich yellowish-brown or russet.   It is very probable that the "Black Oak" and the "Scarlet Oak" ought to be considered as one, and described, not as species and variety, but as slightly different forms of the single species Q. coccinea. Though the most distinctive leaves of the "Black Oak" are easily recognized, often others are so nearly like those of the "Scarlet Oak" that it is not easy to distinguish between then; and the same is true of the fruit and the bark. Michaux f. says: "The only constant difference between the acorns of the Scarlet Oak and the Black Oak is in the kernel, which is white in the Scarlet Oak and yellow in the Black Oak."  The Gray Oak (Q. c., ambigua, Gray) is a variety sometimes found along the northeastern boundary of the States (as far as Lake Champlain) and northward. It combines the foliage of the Red Oak with the acorn of the Scarlet Oak. Quercus, possible from a Celtic word meaning to inquire, because it was among the oaks that the Druids oftenest practised their rites.

Genus Quercus, L. (Oak)

Leaves - simple; alternate; edge lobed (edge of the lobes mostly entire, but oftenest with a few teeth…

The leaf of a Black-jack oak tree.

Black-Jack Oak Leaf

The leaf of a Black-jack oak tree.

Leaves - simple; alternate; lobed (the edge of the lobes entire, or of the larger ones sometimes wavy). Outline - reverse egg-shape. Apex - of the lobes, rounded. Base - wedge-shape. Leaf - six to fifteen inches long (the longest of the oak-leaves); smooth above, downy beneath; the lobes usually long and rather irregular, the middle ones longest and often extending nearly to the middle rib. Bark - of the young branches always marked with corky wings or ridges. Acorns - large, with short stems. Cup - two thirds to two inches across, roughly covered with pointed scales, and heavily fringed around the nut. Nut - very large (one to one and a half inches long); broad egg-shape; one half to two thirds or often wholly enclosed by the cup. Found - along the coast of Maine southward as far as the Penobscot, in Western New England, in Western New York, in Pennsylvania, and thence westward to the foot-hills of the Rocky Mountains of Montana, and from Central Nebraska and Kansas southwest to the Indian Territory and Texas. It is found farther west and northwest than any other oak of the Atlantic forests. In the prairie region it forms a principal growth of the "Oak Openings." General Information - One of the most valuable and widely distributed oaks in North America, growing sixty to eighty feet in height, or more, with hard, tough wood resembling that of the White Oak. "The most interesting thing about this tree, perhaps is its power, quite unknown in the other White Oaks, of adapting itself to very different climatic conditions, which enables it to live in the humid climate of Maine and Vermont, to flourish in the somewhat drier climate of the Mississippi Valley, and to exist (still farther west) in the driest and most exposed region in habited by any of the Eastern America Oaks." - Sargent. Q. m. olivaformis is a variety found only in a few districts (near Albany and in Pennsylvania), having narrower and rather more deeply lobed leaves. Quercus, possible from a Celtic word meaning to inquire, because it was among the oaks that the Druids oftenest practised their rites.

Genus Quercus, L. (Oak)

Leaves - simple; alternate; lobed (the edge of the lobes entire, or of the larger ones sometimes wavy).…

The Charter Oak. This venerable relic is still virgorous, and is a "gnarled oak" indeed. It stands upon the northern slope of the Wyllys Hill, a beautiful elevation on the south side of charter Street, a few rods east of Main Street. This engraving is from a sketch which I made of the tree from Charter Street, on the 3d of October, 1848. I omitted the picket fence in front, in order to show the appearance of the whole trunk.

Charter Oak

The Charter Oak. This venerable relic is still virgorous, and is a "gnarled oak" indeed. It stands upon…

The Charter Oak at Hartford, Connecticut

The Famous charter Oak at Hartford, Connecticut

The Charter Oak at Hartford, Connecticut

Leaves - simple; alternate; edge coarsely and evenly wavy-toothed. Outline - reverse egg-shape or sometimes oval. Apex - blunt-pointed. Base - rounded or slightly pointed, and often somewhat unequal. Leaf - four to seven inches long, two to four inches wide; smooth above, paler and downy beneath. Teeth - twelve to twenty-six, decreasing evenly and uniformly to the apex. Bark - of trunk, gray; furrowed up and down with continuous and often very deep furrows, with sharp ridges between. Acorns - usually in pairs on a stem about one half of an inch long, or often shorter. Cup - rounded or somewhat top-shaped, with minute scales, or warty. Nut - usually long egg-shape or long oval; one to one and one fourth inches long; brown; about one third covered by the cup; sweet. September, October. Found - from Eastern Massachusetts to New York, southward to Delaware, along the Alleghany Mountains to Alabama and westward to Central Kentucky and Tennessee. General Information - A tree forth to seventy feet in height, with strong, hard wood, largely used in fencing, or railroad ties, etc.; of less value than that of the White Oak. Its bark is very rich in tannin. Quercus, possible from a Celtic word meaning to inquire, because it was among the oaks that the Druids oftenest practised their rites.

Genus Quercus, L. (Oak)

Leaves - simple; alternate; edge coarsely and evenly wavy-toothed. Outline - reverse egg-shape or sometimes…

Two men cutting cork, made from the bark of the cork oak (Quercus suber).

Cork

Two men cutting cork, made from the bark of the cork oak (Quercus suber).

The leaf of a English oak tree.

English Oak Leaf

The leaf of a English oak tree.

The epidermis of an oak leaf.

Plant Epidermis

The epidermis of an oak leaf.

The leaf of a mossy-cup oak tree.

Mossy-Cup Oak Leaf

The leaf of a mossy-cup oak tree.

Oaks are easily recognized by their characteristic leaves and especially by their peculiar fruit, the well-known acorn.

Oak

Oaks are easily recognized by their characteristic leaves and especially by their peculiar fruit, the…

Oak trees grow in many parts of the country.

Oak

Oak trees grow in many parts of the country.

Oak trees grow in many parts of the country.

Oak

Oak trees grow in many parts of the country.

A valuable and well known tree, or its wood.

Oak

A valuable and well known tree, or its wood.

A genus of trees and shrubs widely distributed in the temperate zones of all the continents, but most abundant in North America. They are not common to the tropical regions of South America, Africa, or Australia.

Oak

A genus of trees and shrubs widely distributed in the temperate zones of all the continents, but most…

Oak tree leaf

Oak

Oak tree leaf

An illustration of a large oak tree. Oaks have spirally arranged leaves, with a lobed margin in many species; some have serrated leaves or entire leaves with a smooth margin. The flowers are catkins, produced in spring. The fruit is a nut called an acorn, borne in a cup-like structure known as a cupule; each acorn contains one seed (rarely two or three) and takes 6–18 months to mature, depending on species.

Oak

An illustration of a large oak tree. Oaks have spirally arranged leaves, with a lobed margin in many…

"Acorn and cupule of Quercus Skinneri, natural size; 2. cross section of the acorn, showing the lobed embryo." -Lindley, 1853

Acorn

"Acorn and cupule of Quercus Skinneri, natural size; 2. cross section of the acorn, showing the lobed…

An illustration of an oak branch.

Oak Branch

An illustration of an oak branch.

Eastern Black oak (Quercus velutina), or more commonly known as simply Black Oak is an oak in the red oak (Quercus sect. Lobatae) group of oaks. It is native to eastern North America from southern Ontario south to northern Florida and southern Maine west to northeastern Texas. It is a common tree in the Indiana Dunes and other sandy dunal ecosystems along the southern shores of Lake Michigan. It is most often found in dry well draining upland soils which can be clayey or sandy in nature in most of the rest of its range. In the northern part of its range, black oak is a relatively small tree, reaching a height of 20-25 m (65-80 ft) and a diameter of 90 cm (35 in), but it grows larger in the south and center of its range, where heights of up to 42 m (140 ft) are known. Black Oak is well known to readily hybridize with other members of the red oak (Quercus sect. Lobatae) group of oaks being one parent in at least a dozen different named hybrids. he inner bark of the black oak contains a yellow pigment called quercitron, which was sold commercially in Europe until the 1940s.

Eastern Black Oak Branch

Eastern Black oak (Quercus velutina), or more commonly known as simply Black Oak is an oak in the red…

The male flower

Oak Flowers

The male flower

The female flower

Oak Flowers

The female flower

Female flowers of <em>q</em>, pedunculata

Oak Flowers

Female flowers of q, pedunculata

Male flowers of <em>q</em>, sessiliflora

Oak Flowers

Male flowers of q, sessiliflora

Female flowers of <em>q</em>, sessiliflora, after fertilization

Oak Flowers

Female flowers of q, sessiliflora, after fertilization

"Cross-sections of leaves of an oak (Quercus novimexicana), showing the effect of different light conditions on the internal anatomy. 1, from leaf growing in sunlight; 2, from leaf growing in the shade." -Gager, 1916

Oak Leaf Cross-Section

"Cross-sections of leaves of an oak (Quercus novimexicana), showing the effect of different light conditions…

The various types of oak leaves: "a. Bur oak, b. Live oak, c. Willow oak, d. White oak." -Foster, 1921

Oak Leaves

The various types of oak leaves: "a. Bur oak, b. Live oak, c. Willow oak, d. White oak." -Foster, 1921

"Leaf arrangement of the oak." -Bergen, 1896

Oak Leaves

"Leaf arrangement of the oak." -Bergen, 1896

Giant oak with man.

Oak tree

Giant oak with man.

Oak Tree

Oak Tree

Oak Tree

"The Charter Oak. In Hartford the colonial government met to deliver up the charter. It was evening, and the charter lay on the table. Suddenly the candles were blown out. When they were relighted, the character had disappeared. One of the members had it carried it off; and the story is that he hid it in the hollow trunk of the oak which long stood, and bore the name of the Charter Oak."—Scudder, 1897

Charter Oak

"The Charter Oak. In Hartford the colonial government met to deliver up the charter. It was evening,…

The famous oak tree that stood upon the northern slope of the Wyllys Hill, in Hartford.

The Charter Oak

The famous oak tree that stood upon the northern slope of the Wyllys Hill, in Hartford.

An oak seedling.

Oak-seedling

An oak seedling.

Leaves - simple; alternate; edge lobed (edges of the lobes mostly entire, but notched and toothed towards the ends). Outline - narrow oval or broad oval. Base - from long wedge-shape to squared. Ends of lobes and of the teeth pointed and bristle-tipped. Leaf - three to five inches long; both sides bright green, smooth, and shining; downy in the angles of the ribs below. Lobes - seven to nine, usually seven, with the hollows between them broad and round and usually reaching about three fourths of the way or more to the middle rib. The wide type of leaf closely resembles the leaves of the scarlet oak, but it is smaller and usually the hollows reach nearer to the middle rib. Bark - smoothish (comparatively), inner bark reddish. Acorns - numerous, small, on short stems. Cup - top-shaped, shallow, and nearly smooth. Nut - rounded, one half inch long or less, sometimes broader than long, light brown. October. Found - from the valley of the Connecticut to Central New York, southward to Delaware and the District of Columbia; in Southern Wisconsin and southward; usually along streams and on low, wet land. Most common and reaching its finest growth west of the Alleghany Mountains. General Information - A handsome tree forty to sixty feet high, usually with a pointed top and with light and delicate foliage. The wood is rather coarse and not durable. It takes its name of Pin Oak from the peg-like look of the dead twigs and short branches with which the lower parts of the tree are usually set. Quercus, possible from a Celtic word meaning to inquire, because it was among the oaks that the Druids oftenest practised their rites.

Genus Quercus, L. (Oak)

Leaves - simple; alternate; edge lobed (edges of the lobes mostly entire, but notched and toothed towards…

Leaves - simple; alternate; edge lobed (edge of the lobes entire, or sometimes hollowed more or less deeply at the ends.) Outline - usually broad, reverse egg-shape or oval. Apex - of lobes, rounded. Base - wedge shape or round. Leaf - four to six inches long; rough above and below; thick and coarse. The lobes, five to seven and exceedingly variable in size and shape, radiating almost at right angles from the middle rib; sometimes broad and squared, sometimes much narrowed toward their base, with the spreading ends themselves lobed or hollowed; often irregularly and unequally placed. Bark - of the trunk, resembling that of the white oak, but rather darker. Inner bark white. Acorns - two to three together on a short stem (bout one fourth inch), or single and nearly stemless. Cup - round saucer-shape, rather thin, with very small scales, not warty. Nut - about one half inch long; egg-shape or oval; more than one third covered by the cup; shining blackish-brown, and often slightly striped; very sweet. Found - from the coast of Massachusetts southward and westward. General Information - A tree twenty to fifty feet high, of value, especially in the Southwestern States, where it is very common. Quercus, possible from a Celtic word meaning to inquire, because it was among the oaks that the Druids oftenest practised their rites.

Genus Quercus, L. (Oak)

Leaves - simple; alternate; edge lobed (edge of the lobes entire, or sometimes hollowed more or less…

The leaf of a red oak tree.

Red Oak Leaf

The leaf of a red oak tree.

Red oak tree three years after planting.

Red oak three years after planting

Red oak tree three years after planting.

Leaves simple; alternate; edge lobed (edges of the lobes mostly entire, but slightly toothed toward the ends). Outline - about oval.  Base - short wedge-shape, or rounded. Ends of the lobes and of their one to three slight teeth, pointed and bristle-tipped. Leaf - six to nine inches long, three to five inches wide; both surfaces smooth. Lobes, nine to thirteen, usually very tapering from the base, with the hollows between them rounded and narrow and extending about half way to the middle rib. Bark - of trunk, dark, greenish-gray, and continuing smooth longer than on any other oak, never becoming as rough, for example, as that of the black oak. Acorns - large and stemless, or nearly so. Cup - flat saucer-shape, bulging, very shallow, nearly smooth, with small scales. Nut - about one inch long, somewhat egg-shape; bitter. October. Found - from Nova Scotia and New Brunswick westward and southward. Very common, especially at the North, and extending farther north than any other Atlantic oak. General Information - A tree fifty to eight feet high, with wood that at the East is porous and not durable (though often of better quality westward). It is used for clapboards and in cooperage. The leaves change in the fall to dark red. Quercus, possible from a Celtic word meaning to inquire, because it was among the oaks that the Druids oftenest practised their rites.

Genus Quercus, L. (Oak)

Leaves simple; alternate; edge lobed (edges of the lobes mostly entire, but slightly toothed toward…

This shows the staminate flower of Scarlet Oak, Quercus coccinea, (Keeler, 1915).

Scarlet Oak Flowers

This shows the staminate flower of Scarlet Oak, Quercus coccinea, (Keeler, 1915).

This shows the pistillate flower of Scarlet Oak, Quercus coccinea, (Keeler, 1915).

Scarlet Oak Flowers

This shows the pistillate flower of Scarlet Oak, Quercus coccinea, (Keeler, 1915).

The leaf of a scarlet oak tree.

Scarlet Oak Leaf

The leaf of a scarlet oak tree.

Leaves - simple; alternate; edge deeply lobed (edges of lobes mostly entire, but notched and toothed towards the ends). Outline - broadly oval or broadly reverse egg-shape. Base - very short wedge-shape or squared. Ends of the lobes and of the teeth pointed and bristle-tipped. Leaf - four to eight inches long, bright green above, slightly lighter below; both surfaces smooth and shining. Lobes - five to nine, usually seven with the hollows rounded and very broad, and reaching about two thirds of the way to the middle rib. Most of the lobes widen and are deeply notched toward their end. Bark - of trunk, thick and rough, usually not quite as dark or as straight-furrowed as that of the Black Oak. The inner bark reddish. Acorns - variable. Cup - very thick, top-shaped, with large somewhat triangular egg-shaped, scales. Nut - one half to three fourths of an inch long; rounded or rounded egg-shape, about one third covered by the cup; kernel bitter and whitish. October. Found - from Southern Maine southward and westward; most common in the Middle and Southern States. General Information - A tree fifth to ninety feet high, with wood of less value than some of the other oaks. In the fall the leaves turn to a bright scarlet, or orange0scarlet, or crimson and red. They often cling throughout the winter. Quercus, possible from a Celtic word meaning to inquire, because it was among the oaks that the Druids oftenest practised their rites.

Genus Quercus, L. (Oak)

Leaves - simple; alternate; edge deeply lobed (edges of lobes mostly entire, but notched and toothed…