Oak (Ang. Sax. ac), the English name of trees of the genus quercus. Some botanists place all the trees and shrubs which have their unisexual flowers in catkins in one family, the amentacem, while others, including American authorities, make several families, placing quercus, the oak, fagus, the beech, castanea, the chestnut, and two less known genera, in a family by themselves, the cupuliferm, which thus restricted comprises trees (rarely shrubs) the fruit of which consists of nuts contained in an involucral cup (whence the name) or dehiscent capsule. The genus quercus consists of trees and shrubs with alternate simple leaves and monoecious flowers; the staminate flowers are in slender, usually pendulous, often interrupted catkins, the bracts or catkin scales falling early, their flowers consisting of five to twelve stamens within a two- to eight-parted calyx. The fertile or female flowers are solitary or clustered; they have a three-celled ovary with two ovules in each cell, and a three-lobed stigma, and are surrounded by an involucre of small imbricated scales; in fruit the ovary becomes, by abortion of two of the cells and all but one of the ovules, a one-seeded nut (acorn), surrounded at its base by a woody cup, which is formed by the enlarged and indurated scales of the involucre to the ovary.
In his elaboration of the genus, Alphonse de Candolle gives more than 250 accepted species of quercus, some of which have several well marked varieties, and a number of doubtful species. Oaks are found over nearly the whole northern hemisphere, except the extreme north, and in the tropics along the Andes and in the Moluccas. There are both deciduous and evergreen species, presenting a wonderful difference in their leaves and general aspect, some being small shrubs, but all readily recognized by their peculiar fruit, consisting of an acorn and a cup, which never completely encloses the nut. Some of the oaks furnish valuable timber, and one species yields cork. (See Cork.) Tannic and gallic acids are abundant in the oaks, and the bark of many is valuable for tanning, while in some these principles are developed in a remarkable degree in the galls produced by the punctures of insects. (See Galls.) The nuts not only supply human food, but that of various animals. In England in early times the acorns were regarded as the most useful product of the tree, and wooded property was valued according to the number of swine it would support. In some of our western states the mast, or " shack," is an important element in the production of pork.
In the Atlantic states there are about 20 accepted species of oak, with about as many sub-species or varieties. The species vary so much that the genus is puzzling to botanists, and its difficulties are increased by the production of several natural hybrids. The character of the wood is affected by the soil and locality in which the trees grow, and lumbermen make distinctions not recognized by botanists. In some of our oaks the flowers of spring perfect their fruit the same autumn; hence the acorns appear upon the wood of the season's growth, in the axils of the leaves, and often raised on a peduncle or stalk. These are called annual-fruited oaks, and the group is also marked by other characters: the leaves when not entire have their lobes or teeth destitute of bristlelike points; the abortive ovules are found under the seed; the kernel is often sweet, and the timber is more valuable than that of the next section. The biennial-fruited oaks perfect their acorns the year after flowering. After the staminate flowers fall, the pistils undergo little change, but remain until the following spring, when they mature and ripen about 18 months after blossoming.
In these oaks the ripe fruit is found below the growth of the season; the peduncles are short or none, and the kernel bitter; the abortive ovules are at the top of the seed; the leaves when not entire have their lobes terminated by bristlelike points. Each of these sections is subdivided into several smaller groups, characterized by the foliage. - Beginning with the annual-fruited species, the white oak (Q. alba) is one of the most useful as well as most generally distributed. In this, as in others, the leaves present much variety, and trees growing side by side often have leaves sufficiently unlike to belong to different species; they are always deeply lobed, with the lobes obtuse; they are pubescent below when young, smooth when old, shining green on the upper and pale on the under surface; the acorns are about an inch long, in a hemispherical saucer-shaped cup, which is roughened with rounded tubercles; the kernel is usually sweet, but varies in different trees, and the better kinds when roasted are not an unwelcome substitute for chestnuts; the tree fruits so seldom that it is the popular notion that it bears only once in seven years. It is found as far north as Lake Winnipeg, and extends to Florida and the gulf states.
The wood of the white oak, on account of its hardness, toughness, and durability, is regarded as fitted to a greater variety of uses than that of any other tree except the white pine; it is largely employed in ship building, carriage and wagon making, and cooperage, and for various agricultural implements. Among its minor uses is the making of coarse baskets, as the wood of young trees is easily divided into splints of great flexibility and strength; similar splints are used for chair bottoms. The bark is valuable for tanning, and on account of its astringency is used in medicine both internally and as a bath. As a fuel white oak is much inferior to hickory, but it makes excellent charcoal. The white oak is long-lived, and specimens supposed to have been in existence before the settlement of the country are still standing; it is of slow growth, but does not cease to grow as it gets larger. On account of the great value of the wood, the trees are rapidly disappearing, and no provision is made for future supplies. As an ornamental tree the white oak is much esteemed. In autumn the leaves turn to a characteristic purplish color, and remain upon the tree until a new growth begins in spring.
The post oak (Q. obtusiloba), also called rough and box white oak, is smaller, with a denser foliage, and is easily distinguished by its leaves, which are pale and rough above and yellowish downy beneath; their upper lobes are much larger than the lower, and one- to three-notched; the acorn is one half to three fourths of an inch long, ovoid, with a deep saucer-shaped cup one third to one half its length, and a sweet kernel. This tree is found from New England southward, preferring poor and dry soils, and in the western states it is found on the tracts of poor land known as post-oak barrens. It rarely grows over 40 or 50 ft. high and 12 to 18 in. in diameter; it has such a tendency to branch, producing even when growing thickly branches very low down, that it does not afford timber of much length; its wood is fine-grained, strong, yellowish, and regarded as more durable than any other except the live oak; its durability when used for posts has given it its common name; it is considered the best wood for staves, and is used for knees in ship building.
The burr oak (Q. macrocarpa), closely related to the two preceding species, is in some localities known as the over-cup, and in others as the mossy-cup white oak; it is of medium height with irregular branches; its large leaves are obovate in general outline, deeply lobed below the middle, often nearly to the midrib, and broader and more entire toward the apex, smooth and dark green above, and downy or light-colored beneath. The acorn is broadly ovate, 1 to 1½ in. long, and wholly or partly immersed in its cup, which is thick and woody, and very conspicuous, not only on account of its size, but from being covered with prominent scales, the upper of which terminate in leafy points, to form a mossy fringe to the edge of the cup; the relative size of the acorn to the cup varies greatly. The burr oak is much more abundant in the western than in the Atlantic states, and in richer soils than the white and post oaks. When it has room to develop it forms a handsome tree; and as it grows more rapidly than most other oaks, it is well adapted to ornamental planting, while the value of its timber, being nearly equal to that of white oak, renders it desirable for forest planting.
As its wood is preferred for making the treenails or wooden pins used in ship building, this species is in some parts of New England called pin oak, a name which properly belongs to another species. The southern over-cup oak (Q. lyratd) is found in swamps along rivers from North Carolina south and west, where it forms a large tree, 70 to 80 ft. high, with its seven to nine triangularly lobed leaves crowded at the ends of the branches. The acorns are an inch long and considerably broader, and enclosed in a cup which is clothed with rugged scales and almost conceals the nut. - In the group of chestnut oaks the leaves are not lobed (except slightly in one species), but are coarsely sinuate-toothed, and white or whitish-downy beneath; the cup hoary, hemispherical or somewhat depressed, about half as long as the oblong-ovoid edible acorn. The swamp white oak (Q. bicolor) is found in low grounds, especially in the northern and western states, and frequently attains a large size; its leaves are intermediate between the chestnut and white oaks, being sometimes simply sinuate on the margin, and at others more pinnatifid than toothed, but in all cases wedge-shaped at the base, and hoary beneath with a soft down.
After flowering the foot stalk elongates, and when the fruit is mature is 2 or 3 in. long, or longer than the petioles, and bears one or two acorns an inch long; the cup has its upper scales awn-pointed, and sometimes forming a mossy fringe around the edge. The wood is brownish, heavy, and compact; its uses are similar to those of white oak. The chestnut oak (Q. prinus) has given botanists much trouble on account of its variable character. The leading form is popularly known as the swamp chestnut oak; it has obovate or oblong leaves undulately toothed on the margin, minutely downy beneath, with 10 to 16 pairs of straight rather prominent primary ribs. The fruit-bearing stalk is shorter than the petioles; the acorn is an inch or less in length, with a thick cup covered with hard stout scales. This is found from Pennsylvania southward, and is most plentiful in the Caro-linas and Georgia, inhabiting moist and dry soil, and differing much in size and the quality of its wood according to its situation. It makes durable rails.
A variety of this is the rock chestnut oak (var. montieola), given in some works as a species (Q. montana); it is found in or near the mountains, from Vermont southward, and forms a tree 30 or 40 ft. high; it has large acorns, like the preceding, and more chestnut-like leaves; it produces greatly superior timber, and is highly esteemed as fuel. It is a most valuable tree for planting upon rocky hillsides, in situations which can never be cultivated. Another variety is the yellow chestnut oak (var. acuminata), which is the quercus castanea of Muhlenberg and other authors. It has leaves more like the chestnut than the others, as they are on slender petioles and oblong or lanceolate from a rounded base, equally and sharply toothed and with very straight veins. The acorns are rather small, very sweet, with a thin hemispherical cup, having appressed scales. This variety is a handsome tree 60 to 70 ft. high; it is more abundant in the middle states than northward, and extends to Florida. Its wood is very yellow, strong, and durable. Not only is there some confusion in the botanical nomenclature of oaks, but the common names are carelessly applied; in the western states the yellow chestnut oak is called chinquapin oak, a name that belongs to the variety humilis mentioned below.
Another variety of Q. prinus is Michaux's oak (var. Michauxii of Chapman), a large tree found in low grounds from South Carolina to Florida; it has smaller and more rigid leaves than the rock chestnut oak, velvety underneath, and obtuse or slightly cordate at base, with a nut 1½ in. long. The smallest variety of this species, the chinquapin oak (var. humilis), is sometimes called the dwarf chestnut oak. It is the smallest of the northern oaks, being usually 2 or 3 ft. high, and seldom above 5 ft. Some botanists regard this as a distinct species, and it has several different botanical names. It is found from southern New England and New York south and westward in sandy barrens, where it often forms the sole vegetation of many acres. It produces its small acorns very abundantly, and affords food for animals. - The live oak (Q. virens) also belongs to the annual-fruited oaks, and is distinguished from all the eastern species of this section by its thick, evergreen leaves, which are entire, or in one variety with spiny teeth. Its leaves are 2 to 4 in. long, oblong, obtuse, smooth and shining above, and as well as the branchlets hoary beneath; the fruit stalk is conspicuous, bearing one to three fruits; acorn oblong, chestnut-brown, with a top-shaped, hoary cup.
This is usually a large, much-branched tree, found from Virginia to Texas, and seldom more than 50 m. inland from the coast; it also extends into Mexico and Central America, and is found in some of the West India islands. The wood of this species is yellowish, fine-grained, and of exceedingly slow growth; it is considered of greater value than any other for ship building, and is highly prized by all maritime nations; the tree usually branches low, and it therefore supplies an abundance of knees; it is also of great value to the wheelwright and the millwright. A seaside variety (var. maritima) has acute leaves, larger fruit, and does not exceed 10 ft. in height; and a still smaller form (var. dentata) is found in the pine barrens of Florida, only 1 or 2 ft. high, with the earliest leaves toothed and nearly sessile, and the fruit short-peduncled or nearly sessile. - The characters of the biennial-fruited oaks have been described; these, like the annual-fruited species, are in groups, one of which is the willow oaks, which are nearly or quite evergreen at the south, their leaves generally entire, and the acorn globose.
The upland willow oak (Q. cinerea) is a small worthless tree of the pine barrens from Virginia southward, resembling the live oak, from which it is distinguished by its narrower, more downy leaves, and its globular acorn. The willow oak (Q. phellos) is distinguished from all other oaks by its willow-like leaves, which are from 3 to 4 in. long, and smooth when old; the flat cup encloses the base of the hemispherical nut. It is slender, 30 to 50 ft. high, and found along swamps and streams from Long island to Florida; its timber is of little value; it is planted in some of the southern cities as a shade tree. The variety laurifolia is a larger tree with longer and broader leaves, and the variety arenaria is a mere shrub with smaller leaves. The shingle oak (Q. imbricaria), also called the laurel oak, has lance-oblong leaves, which are smooth above and downy beneath; it grows from 30 to 50 ft. high, and is found from New Jersey south and west. Its wood, though hard, is poor; it is used for shingles in some of the western states. The water oak (Q. aquatka) is small and very variable, growing in wet places from Maryland to Florida; it has a smooth bark and usually wedge-shaped, smooth, and shining leaves, which are sometimes lobed and bristle-pointed; the wood is tough but not durable.
Related to the preceding in the shape and variableness of its foliage is the black-jack (Q. nigra), which grows on sandy barrens from southern New York to Florida, and westward to Illinois; it is readily distinguished by the wedge-shaped leaves, which are conspicuously broad at the summit and often bristle-pointed, shining above and rusty beneath; the cup is top-shaped, with coarse scales. This tree rarely exceeds 30 ft., and is usually much smaller; its wood is of little value save for fuel. Lea's oak (Q. Leana), Bartram's oak (Q. heterophylla), and several others, are regarded as hybrids of the preceding biennial species with others. - The black and red oaks make another group of biennial species; these all have pinnatiiid or lobed, long-petioled, deciduous leaves. The smallest is the bear or black scrub oak (Q. iliafolia), which is found on rocky hills and sandy plains from New England to Kentucky; it is 3 to 8 ft. high, with obovate leaves, ridge-shaped at base, about five-lobed, and abundantly downy beneath; acorn ovoid, often beautifully striped, with a deep orange kernel; as it produces a great number of scraggy branches, it has been suggested as a hedge plant for poor lands.
The Spanish oak (Q.yalcata) was so called by the Spanish settlers in the south from its resemblance to the common oak of Spain; it is distinguished by the falcate or scythe-shaped lobes of its leaves, which are grayish or yellowish-downy beneath; it is found in dry localities from New Jersey to Florida and to Illinois; when growing alone it is very handsome, sometimes 80 ft. high; its wood is porous and unlit for barrels to contain liquids, but is sometimes used for felloes; its bark is valuable for tanning, and is said to color the leather less than that of any other oak. The remainder of this group have their much-lobed, usually ovate leaves smooth on both sides, and turning some shade of red in autumn. The Turkey or pine-barrens scrub oak (Q. Catesboei) grows in North Carolina and southward, on land too poor to sustain any other vegetation; it has thicker leaves than any others of this group, and a thick cup with coarse scales; it is small and of no value save for fuel. - The scarlet oak (Q. coccinea) is one of the commonest species, and is found, usually in dry soil, over a wide range from north to south; it is, except northward, large and handsome, with leaves deeply pinnatifid, and the lobes often toothed, bright green, shining, and in autumn turning to a beautiful scarlet; the acorn is about three fourths of an inch long, more than half covered by the coarsely scaly cup; the scar of the acorn within the cup as well as its flesh is white or yellowish.
The black, quercitron, or yellow-barked oak, formerly regarded as a species, is now placed as var. iinctoria of the preceding. Although extreme forms are readily distinguished by differences in the leaves and fruit, yet in many cases it is impossible to decide whether a specimen is a scarlet or a black oak without cutting into the bark, which in the latter is much thicker, and orange-colored within; the kernel of the acorn is yellowish, find its seat within the cup is orange-colored; in autumn the foliage turns a rich yellowish brown, russet, orange, or dull red. While the wood of the species is of little value even for fuel, that of the variety is second only to white oak, and much used by ship builders and wagon makers. The bark contains much tannin and an abundant coloring matter; it is valuable for tanning and dyeing, for which use large quantities are yearly exported. (See Quercitron.) There are other forms of the scarlet oak, probably hybrids. The red oak (Q. rubra) has an equally wide range with the scarlet and black oaks, and extends further north than any other; it has less deeply lobed leaves, which turn to a dark red before they fall, and the acorn cup is broader and shallower.
Its wood is of little value for timber or fuel, but the tree itself is very ornamental. - In the states on the Pacific coast each of the groups here mentioned is represented either by species peculiar to those regions, or by forms so like the eastern species that botanists regard them as varieties; the oaks there are even more variable than those of the Atlantic coast, and as each botanist who has studied them has come to different conclusions from his predecessors, the subject is somewhat confused, and only a few of the more striking species will be mentioned. Garry's oak (Q. Garry ana) is found from Washington territory southward to California, varying in height from 30 to 80 ft.; it belongs to the same group with the white oaks, and has the under side of the leaves covered with a dense dingy down; it branches low down, and at a distance a grove of it looks like an apple orchard; this is one of the species of which the nuts are gathered for food by the Indians, and its wood is considered nearly equal to that of the white oak for ship building.
Another of the white oak group is Q. lobata, given in the various reports as Q. Hindsii, though the former is the older name; this is regarded as the finest species on the Pacific coast, and one of the most abundant; it has a thick and rough bark, leaves shaped much like those of our white oak, and acorns often 2 in. long and pointed, but varying in this respect. It often reaches a diameter of 6 to 8 ft. and a height of 50 to 75 ft., with wide-spreading branches; the wood is brittle and porous, and the nut edible. Douglas's oak (Q. Douglasii) is smaller, but very difficult to distinguish from some forms of the preceding. The chestnut oak of California is Q. densiflora, and an evergreen; it is a small handsome tree of the foot hills south of San Francisco; its foliage is very variable, being sometimes entire, but often toothed like that of the chestnut, its resemblance to that tree being carried out in the acorn cup, which is densely covered with long spreading scales and appears much like a chestnut burr.
Another evergreen species is Q. chrysolepis, which upon the Sierra Nevada is a mere shrub, but on the foot hills is 40 ft. high, with usually entire leaves, yellowish downy beneath; the acorn is about an inch long, with a remarkably thick and velvety cup, on account of which Torrey called it Q. crassipoeula, and from its yellowish pubescence it was named Q.falvencens by Kellogg, both of which names are more recent than that here adopted. The variable tree known in California as the scrub or evergreen oak is Q. agrifolia, which extends from the valley of the Sacramento to the Mexican border; it is, according to locality, a large shrub or a tree 30 or 40 ft. high; its leaves, which are as variable as in the other species, are often sharply toothed, and the acorns elongated, acute, and sometimes very narrow, like a cockspur. - The European or British oak, or royal oak as it is often called, appears to vary quite as much as some of our species, different forms having been described as distinct species, and botanists are not agreed in regard to one of the commonest and most important European plants.
Hooker and Bentham make but one species, Q. robur, and place what others call Q. sessiliflora and Q. pedunculata as varieties of this, with the same names for the varieties as others give to the species. Q. robur is found over the whole of Europe except at the extreme north, and extends into Asia along the Caucasus; it is the oak of poetry and history, and is one of the stateliest and longest-lived of the genus. It belongs to the same section with our white oaks, but has smaller leaves, which are not whitened beneath, and they are not deeply lobed; the oblong acorn is over an inch long, in a short cup which is covered with short, obtuse, closely imbricated scales. In the variety sessiliflora the fruits are solitary or few in a cluster, nearly sessile in the axils of the leaves, which have petioles half an inch to an inch long, while in the variety pedunculata the fruits are clustered above the middle of a slender stalk, which varies from 1 to even 6 in. long; the leaves vary from sessile to short-petioled.' The first named is more abundant in North Wales and the hilly portions of northern England, while the other is the commonest over the greater part of England and the lowlands of Scotland. In durability the timber of the two varieties is regarded as equal; but as that of the pedunculate oak shows more of the silver grain, it is more valuable for cabinet work than the other.
Each of these varieties has a dozen or more sub-varieties, marked by a distinct habit of growth or some striking form of foliage, which are made use of in ornamental planting. Some of the oaks now standing in England were old trees at the time of the conquest, and their remains so long as they retain any vitality are cherished with reverent care. This oak succeeds remarkably in the United States, and to judge from the size of the older specimens now growing, it will after some centuries become even larger than in its native country. The Turkey oak (Q. cerris), a native of the southern parts of Europe, succeeds well in this country; its short-petioled leaves are deeply and unequally pinnated, and downy beneath; the cup of the acorn is covered with bristly scales, on which account it is often called in England the mossy-cup oak. This has also produced several varieties, some of singular beauty; some are very spreading, and others are almost evergreen even in America, holding their foliage nearly to Christmas. The timber of the Turkey oak is regarded as equal in value to that of the British oak.
The common evergreen species of Europe is the holm or holly oak (Q. ilex), abundant in the southern countries, especially in Italy and Spain, and extends to northern Africa and to Asia; it grows naturally on hilly ground near the sea, and in England has been found to grow upon the seashore where no other oak will live. It is a low or middle-sized tree, and is furnished with branches down to the ground, but if pruned may be made to grow much taller with a clean trunk; its leaves are thick, and either entire or toothed like those of the holly; its wood is brown at the heart, fine-grained, hard, tough, elastic, and remarkably heavy, and greatly esteemed for ship building. It is a long-lived tree, and is the oak of Pliny and the early historians. In England it is used in ornamental planting and for screens; it is not hardy in our northern states. - The acorns of several California!, species furnish a large share of the winter food of the Indians of the western coast. They are powdered in a mortar, and the meal, after washing it to remove the bitterness, is made into cakes or mush. An evergreen species, Q. ballota, abundant in Algeria and Morocco, has large nuts which are eaten raw or roasted.
The acorns of the Gra-mont oak (Q. Gramuntia) of Spain, when in perfection, are regarded as even superior to chestnuts, and are much eaten. Besides the use of the bark in tanning (see Leatiiee), a secondary one is of some importance in horticulture; a mass of the spent tan bark gradually ferments and gives off a mild heat, which, though more gentle than that from manure, is long continued and especially adapted to some plants, particularly the pineapple. In the valonia oak (Q. oegilops) of the Grecian islands and throughout Greece, the tannin is so abundantly secreted in the acorn cups that these form an article of commerce under the name of valonia; the tree is large, with foliage much like that of our chestnut oaks, and large acorns, the cups of which are about 2 in. across, hemispherical, and clothed with large reflexed woody scales. Two varieties are also known in commerce: camata, which is the half-grown acorns dried in their cups, and camatina, which is the undeveloped acorns gathered soon after flowering when about the size of large peas; these last are much richer in tannin than the other two.
Besides the yellow dye of the quercitron oak, a crimson one is furnished by Q. cocci/era, found in the Levant; its leaves arc much infested by a scale insect, a species of coccus, which when it has completed its growth has every appearance of a berry, and is known as kermes. (See Cochineal.) The oak manna of Kurdistan, usually ascribed to Q. mannifera, is, according to Ilaussknecht, afforded by Q. vallonea and Q. Persica; the twigs are visited by myriads of a small white coccus, and from the punctures made by these exudes a saccharine fluid which solidifies in small grains; this is collected by the wandering tribes, who use it as a substitute for sugar. - Oaks form very long perpendicular tap roots, and in cultivation when the plants are a year old they should be transplanted, and at the same time the tap root be shortened; by frequent transplanting thereafter, trees may be obtained with a good share of small roots, and such may be removed without difficulty. In planting for timber or for ornament, except in streets, the surer way is to put in several acorns where the trees are to stand, and when the plants are two or three years old remove all but one.
Although so hardy and robust when old, the oak is exceedingly tender during its first few years; and in England it is customary to provide "nurse trees," which shade and protect the oaks until they become thoroughly established. - There are many fine oaks in Japan and northern China, as well as in the mountainous parts of Mexico and the Himalayas.
White Oak (Qucrcus alba).
White Oak Tree.
Post or Rough White Oak (Qucrcus obtusiloba).
Burr or Over-cup Oak (Quercus macrocarpa).
Swamp White Oak (Quercus bicolor).
Rock Chestnut Oak (Quercus prinus, var. monticola).
Live Oak (Quercus virens).
Live Oak Tree.
Willow Oak (Quercus phellos).
Bear or Black Scrub Oak (Quercus ilicifolia).
Scarlet Oak (Quercus cocciuea).
California Evergreen Oak (Quercus agrifolia).
European Oak (Quercus robur). 1. Var. sessiliflora. 2. Var. pedunculata.
Valonia Oak (Quercus a)gilops).