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How to tell them from other trees and from each other: The hickory trees, though symmetrical, have a rugged appearance and the branches are so sturdy and black as to give a special distinction to this group. The buds are different from the buds of all other trees and sufficiently characteristic to distinguish the various species of the group. The bark is also a distinguishing character.
The walnut and butternut have chambered piths which distinguish them from all other trees and from each other.
Distinguishing characters: The yellowish brown buds nearly as large as those of the mockernut hickory, are each provided with two long, dark, outer scales which stand out very conspicuously as shown in Fig. 67. The bark in older specimens shags off in rough strips, sometimes more than a foot long, as shown in Fig. 68. These two characters will readily distinguish the tree at all seasons of the year.
Leaf: The leaf is compound, consisting of 5 or 7 leaflets, the terminal one generally larger.
Form and size: A tall, stately tree—the tallest of the hickories—of rugged form and fine symmetry, see Fig. 66.
Range: Eastern North America.
Soil and location: The shagbark hickory grows in a great variety of soils, but prefers a deep and rather moist soil.
Enemies: The hickory bark borer ( Scolytus quadrispinosus ) is its principal enemy. The insect is now killing thousands of hickory trees in the vicinity of New York City and on several occasions has made its appearance in large numbers in other parts of the country.
Value for planting: It is difficult to transplant, grows slowly and is seldom found in nurseries.
Commercial value: The wood is extremely tough and hard and is used for agricultural implements and for the manufacture of wagons. It is excellent for fuel and the nuts are of great value as a food.
Other characters: The fruit is a nut covered by a thick husk that separates into 4 or 5 segments. The kernel is sweet.
Other common names: Shellbark hickory .
Distinguishing characters: The bud is the largest among the hickories—nearly half an inch long—is hard and oval and covered with yellowish brown downy scales which do not project like those of the shagbark hickory, see Fig. 69. The twigs are extremely coarse. The bark is very tight on the trunk and branches and has a close , hard, wavy appearance as in Fig. 70.
Leaf: The leaf consists of 5, 7 or 9 leaflets all of which are large and pubescent and possess a distinct resinous odor.
Form and size: A tall tree with a broad spreading head.
Range: Eastern North America.
Soil and location: The mockernut hickory grows on a great variety of soils, but prefers one which is rich and well-drained.
Enemies: The same as for the shagbark hickory.
Value for planting: It is not commonly planted.
Commercial value: The wood is similar to that of the shagbark hickory and is put to the same uses.
Other characters: The fruit is a nut, larger and covered with a shell thicker than that of the shagbark. The husk is also thicker and separates into four segments nearly to the base. The kernel is small and sweet.
Other common names: Bigbud hickory ; whiteheart hickory .
Comparisons: The pignut hickory ( Hicoria glabra ), sometimes called broom hickory or brown hickory, often has a shaggy bark, but differs from both the shagbark and the mockernut hickory in possessing buds very much smaller, twigs more slender and leaflets fewer. The nut has a thinner husk which does not separate into four or five segments. The tree prefers drier ground than the other hickories.
The bitternut ( Hicoria minima ) can be told from the mockernut and other species of hickory by its bud, which has no scales at all. The color of its bud is a characteristic orange yellow. The bark is of a lighter shade than the bark of the mockernut hickory and the leaflets are more numerous than in any of the hickories, varying from 7 to 11. Its nuts are bitter.
Distinguishing characters: By cutting a twig lengthwise, it will be seen that its pith is divided into little chambers as shown in Fig. 71. The bud is dark gray and satiny. The bark is dark brown and deeply ridged and the fruit is the familiar round walnut.
Form and size: A tall tree with a spreading crown composed of stout branches. In the open it grows very symmetrically.
Range: Eastern United States.
Soil and location: The black walnut prefers a deep, rich, fertile soil and requires a great deal of light.
Enemies: The tree is a favorite of many caterpillars.
Value for planting: It forms a beautiful spreading tree on open ground, but is not planted to any extent because it is hard to transplant. It grows slowly unless the soil is very deep and rich, develops its leaves late in the spring and sheds them early in the fall and produces its fruit in great profusion.
Commercial value: The wood is heavy, strong, of chocolate brown color and capable of taking a fine polish. It is used for cabinet making and interior finish of houses. The older the tree, usually, the better the wood, and the consumption of the species in the past has been so heavy that it is becoming rare. The European varieties which are frequently planted in America as substitutes for the native species yield better nuts, but the American species produces better wood.
Other characters: The fruit is a large round nut about two inches in diameter, covered with a smooth husk which at first is dull green in color and later turns brown. The husk does not separate into sections. The kernel is edible and produces an oil of commercial value.
The leaves are compound and alternate with 15 to 23 leaflets to each.
Comparisons: The butternut ( Juglans cinerea ) is another tree that has the pith divided into little chambers, but the little chambers here are shorter than in the black walnut, as may be seen from a comparison of Figs. 71 and 72. The bark of the butternut is light gray while that of the black walnut is dark. The buds in the butternut are longer than those of the black walnut and are light brown instead of gray in color. The form of the tree is low and spreading as compared with the black walnut. The fruit in the butternut is elongated while that of the black walnut is round. The leaves of the butternut have fewer leaflets and these are lighter in color.
Distinguishing characters: There are four characters that stand out conspicuously in the tulip tree—the bud , the trunk , the persistent fruit cups and the wedged leaf .
The bud, Fig. 74, about three-quarters of an inch long, is covered by two purplish scales which lend special significance to its whole appearance. The trunk is extremely individual because it rises stout and shaft-like, away above the ground without a branch as shown in Fig. 73. The tree flowers in the latter part of May but the cup that holds the fruit persists throughout the winter. The leaf, Fig. 75, has four lobes, is nearly as broad as it is long and so notched at the upper end that it looks different from any other leaf.
Form and size: The tulip tree is one of the largest, stateliest and tallest of our trees.
Range: Eastern United States.
Soil and location: Requires a deep, moist soil.
Enemies: Comparatively free from insects and disease.
Value for planting: The tree has great value as a specimen on the lawn but is undesirable as a street tree because it requires considerable moisture and transplants with difficulty. It should be planted while young and where it can obtain plenty of light. It grows rapidly.
Commercial value: The wood is commercially known as whitewood and yellow poplar . It is light, soft, not strong and easily worked. It is used in construction, for interior finish of houses, woodenware and shingles. It has a medicinal value.
Other characters: The flower , shown in Fig. 75, is greenish yellow in color, appears in May and resembles a tulip; hence the name tulip tree. The fruit is a cone.
Other common names: Whitewood ; yellow poplar ; poplar and tulip poplar .
Distinguishing characters: The persistent, spiny , long-stemmed round fruit ; the corky growths on the twigs , the characteristic star-shaped leaves (Fig. 76) and the very shiny greenish brown buds and the perfect symmetry of the tree are the chief characters by which to identify the species.
Form and size: The sweet gum has a beautiful symmetrical shape, forming a true monopodium.
Range: From Connecticut to Florida and west to Missouri.
Soil and location: Grows in any good soil but prefers low wet ground. It grows rapidly and needs plenty of light.
Enemies: Is very often a favorite of leaf-eating caterpillars.
Value for planting: The tree is sought for the brilliant color of its foliage in the fall, and is suitable for planting both on the lawn and street. In growing the tree for ornamental purposes it is important that it should be frequently transplanted in the nursery and that it be transported with burlap wrapping around its roots.
Commercial value: The wood is reddish brown in color, tends to splinter and is inclined to warp in drying. It is used in cooperage, veneer work and for interior finish.
Other characters: On the smaller branches there are irregular developments of cork as shown in Fig. 76, projecting in some cases to half an inch in thickness.
Other common names: Red gum .
Comparisons: The cork elm is another tree that possesses corky ridges along its twigs, but this differs from the sweet gum in wanting the spiny fruit and its other distinctive traits.
Distinguishing characters: The great distinguishing feature of any linden is the one-sided character of its bud and leaf . The bud, dark red and conical, carries a sort of protuberance which makes it extremely one sided as shown in Fig. 77. The leaf, Fig. 78, is heart-shaped with the side nearest the branch largest.
Form and size: The American Linden is a medium-sized tree with a broad round head.
Range: Eastern North America and more common in the north than in the south.
Soil and location: Requires a rich, moist soil.
Enemies: Its leaves are a favorite food of caterpillars and its wood is frequently attacked by a boring insect known as the linden borer ( Saperda vestita ).
Value for planting: The linden is easily transplanted and grows rapidly. It is used for lawn and street planting but is less desirable for these purposes than the European species.
Commercial value: The wood is light and soft and used for paper pulp, woodenware, cooperage and furniture. The tree is a favorite with bee keepers on account of the large quantities of nectar contained in its flowers.
Other characters: The fruit is like a pea, gray and woody. The flowers appear in early July, are greenish-yellow and very fragrant.
Other common names: Bass-wood ; lime-tree ; whitewood .
Comparisons: The European lindens , Fig. 79, of which there are several species under cultivation, differ from the native species in having buds and leaves smaller in size, more numerous and darker in color.
The various species of magnolia trees are readily distinguished by their buds. They all prefer moist, rich soil and have their principal value as decorative trees on the lawn. They are distinctly southern trees; some species under cultivation in the United States come from Asia, but the two most commonly grown in the Eastern States are the cucumber tree and the umbrella tree.
Distinguishing characters: The buds are small and slender compared with those of the other magnolia trees and are with small silvery silky hairs . The habit of the tree is to form a straight axis of great height with a symmetrical mass of branches, producing a perfect monopodial crown. The tree is sometimes known as mountain magnolia .
Distinguishing characters: The buds , Fig. 80, are extremely long , often one and a half inches, have a purple color and are smooth . The tree does not grow to large size and produces an open spreading head. Its leaves, twelve to eighteen inches long, are larger than those of the other magnolia trees. The tree is sometimes called elkwood .
Distinguishing characters: The bark of the trunk is rough and deeply ridged , as shown in Fig. 81. The buds are hardly noticeable ; the twigs sometimes bear small spines on one side. The leaves are large, compound, and fern-like. The individual leaflets are small and delicate.
Form and size: The locust is a medium-sized tree developing a slender straight trunk when grown alongside of others; see Fig. 82.
Range: Canada and United States.
Soil and location: The locust will grow on almost any soil except a wet, heavy one. It requires plenty of light.
Enemies: The locust borer has done serious damage to this tree. The grubs of this insect burrow in the sapwood and kill the tree or make it unfit for commercial use. The locust miner is a beetle which is now annually defoliating trees of this species in large numbers.
Value for planting: It has little value for ornamental planting.
Commercial value: Though short-lived, the locust grows very rapidly. It is extremely durable in contact with the soil and possesses great strength. It is therefore extensively grown for fence-posts and railroad ties. Locust posts will last from fifteen to twenty years. The wood is valuable for fuel.
Other characters: The flowers are showy pea-shaped panicles appearing in May and June. The fruit is a small pod.
Other common names: Yellow locust ; common locust ; locust .
Comparisons: The honey locust ( Gleditsia triacanthos ) can be told from the black locust by the differences in their bark. In the honey locust the bark is not ridged, has a sort of dark iron-gray color and is often covered with clusters of stout, sharp-pointed thorns as in Fig. 83. The fruit is a large pod often remaining on the tree through the winter. This tree has an ornamental, but no commercial value.
Distinguishing characters: The tree may be told by its fruit , which hang in long slender pods all winter. The leaf-scars appear on the stem in whorls of three and rarely opposite each other.
Form and size: The catalpa has a short, thick and twisted trunk with an irregular head.
Range: Central and eastern United States.
Soil and location: It grows naturally on low bottom-lands but will also do well in poor, dry soils.
Enemies: Practically free from disease and insects.
Value for planting: The catalpa grows very rapidly and is cultivated in parks for ornament and in groves for commercial purposes. The hardy catalpa is preferable to the common catalpa for planting.
Commercial value: The wood is extremely durable in contact with the soil and is consequently used for posts and railroad ties.
Other characters: The flowers , which appear in late June and early July, are large, white and very showy.
Other common names: Indian bean ; western catalpa .
Comparisons: The white flowering dogwood ( Cornus florida ) is a small tree which also has its leaves in whorls of three or sometimes opposite. It can be readily told from other trees, however, by the small square plates into which the outer bark on the trunk divides itself, see Fig. 85, and by the characteristic drooping character of its branches. It is one of the most common plants in our eastern deciduous forests. It is extremely beautiful both in the spring and in the fall and is frequently planted for ornament. There are many varieties of dogwood in common use.
A small tree recognized by its small round reddish brown buds and light brown, finely furrowed (wavy looking) bark .
The tree, probably a native of China, is grown under cultivation in eastern Canada and United States. It grows rapidly in moist soil and is not fastidious in its light requirements. Its chief value is for screening and for underplanting in woodlands.
The red mulberry ( Morus rubra ) is apt to be confused with the white mulberry, but differs in the following characters: The leaves of the red mulberry are rough on the upper side and downy on the under side, whereas the leaves of the white mulberry are smooth and shiny. The buds in the red are larger and more shiny than those of the white.
The Osage orange ( Toxylon pomiferum ) is similar to the mulberry in the light, golden color of its bark, but differs from it in possessing conspicuous spines along the twigs and branches and a more ridged bark.