Part 5

THE black locust is a native to the Appalachian Mountains but has been introduced into Illinois, and now occurs throughout the entire State growing on all soils and under all conditions of moisture except in swamps. It is found generally in thickets on clay banks and waste places or along fence rows.

The twigs and branchlets are armed with straight or slightly curved sharp, strong spines, sometimes as much as 1 inch in length which remain attached to the outer bark for many years. The _bark_ is dark brown and divides into strips as the tree grows older.

The _leaves_ are pinnate, or featherlike, from 6 to 10 inches in length, consisting of from 7 to 19 oblong thin leaflets.

The _flowers_ are fragrant, white or cream-colored, and appear in early spring in graceful pendent racemes. The _fruit_ is a pod from 3 to 5 inches long containing 4 to 8 small hard seeds which ripen late in the fall. The pod splits open during the winter, discharging the seeds. Some seeds usually remain attached to each half of the pod; the pod thus acts as a wing upon which the seeds are borne to considerable distances before the strong spring winds.

The _wood_ is yellow in color, coarse-grained, very heavy, very hard, strong, and very durable in contact with the soil. It is used extensively for fence posts, poles, tree nails, insulator pins and occasionally for lumber and fuel.

The tree is very rapid in growth in youth but short-lived. It spreads by underground shoots and is useful for holding and reclaiming badly gullied lands. The usefulness of the black locust is, however, very greatly limited by the fact that it is subject to great damage from an insect known as the locust borer.

+TREE OF HEAVEN+ _Ailanthus altissima_ Swingle

THIS tree is a native of China but planted in Illinois because of its tropical foliage. It has escaped and become naturalized. It is a handsome, rapid-growing, short-lived tree, attaining a height of 40 to 60 feet, and a trunk diameter of 2 to 3 feet. Its crown is spreading, rather loose and open. The twigs are smooth and thick with a large reddish-brown pith. The _winter buds_ are small, globular and hairy, placed just above the large leaf-scars.

The _leaves_ are alternate, pinnately compound and one to three feet long. The leaflets number from 11 to 41, are smooth, dark green above, paler beneath, turning a clear yellow in autumn.

The _flowers_ appear soon after the leaves are full grown, on different trees, borne in large upright panicles. They are small yellow-green in color with 5 petals and 10 stamens. The staminate flowers have a disagreeable odor.

The _fruit_, ripening in October but remaining on the tree during the winter, is a one-seeded samara, spirally twisted, borne in crowded clusters.

The tree of heaven is useful for landscape planting, succeeding in all kinds of soils and all kinds of growing conditions. It makes a rapid showing and is practically free from all diseases and insect injury.

+SMOOTH SUMAC+ _Rhus glabra_ L.

THE smooth sumac is usually a tall shrub but occasionally it develops as a tree 20 to 25 feet tall with a trunk diameter of 6 to 10 inches. A few large spreading branches form a broad, flat, open head. The twigs are smooth and glabrous and have a thick, light brown pith with small round winter buds.

The compound _leaves_ are 6 to 18 inches long, composed of 9 to 27 leaflets with sharply notched margins. They are dark green above, whitish beneath, changing to red, purple and yellow early in the autumn.

The _flowers_ are small and green, produced in dense terminal panicles. The _fruit_ is a small globose berry, covered with crimson hairs and has a pleasant acid taste. The conspicuous deep red panicles of fruit remain unchanged on the tree during the winter.

The _wood_ is light and of a golden yellow color. Either as a tree, or as a shrub, the smooth sumac is excellent for ornamental planting, being particularly desirable on terraces or hillsides, where mass effects are desired. It transplants very readily and spreads freely.

The staghorn sumac, _Rhus typhina_ L., is a slightly taller tree, as it reaches a height of 20 to 35 feet, and a stem diameter of 8 to 12 inches. The twigs and leaves are similar to those of the smooth sumac but are conspicuously hairy. Its occurrence is limited to the northern part of the State.

The shining sumac, _Rhus copallina_ L., usually occurs in shrub form but it occasionally reaches a height of 20 feet with a stem diameter of 6 inches. The leaves are smooth above but somewhat hairy beneath with a winged rachis and about 9 to 21 leaflets that are slightly toothed. Late in the summer its foliage turns a brilliant red. The fruit clusters are much smaller than the preceding species. It is found throughout the State.

+SUGAR MAPLE+ _Acer saccharum_ Marsh.

THE sugar maple is an important member of the climax forests which stretch from Maine to Minnesota and southward to Texas and Florida. It is an associate of the hemlocks and the birches in the North, with the beeches and chestnuts through the middle states, with the oaks in the West and with the tulip and the magnolias in the South. In Illinois it is a common and favorite tree throughout the State. In the open it grows fairly rapidly and has a very symmetrical, dense crown, affording heavy shade. It is, therefore, quite extensively planted as a shade tree. The _bark_ on young trees is light gray and brown and rather smooth, but as the tree grows older, it breaks up into long, irregular plates or scales, which vary from light gray to almost black. The twigs are smooth and reddish-brown, and the _winter buds_ are smooth and sharp-pointed. The tree attains a height of more than 100 feet and a diameter of 3 feet or more. The sap yields maple sugar and maple syrup.

The _leaves_ are 3 to 5 inches across, simple, opposite, with 3 to 5 pointed and sparsely-toothed lobes, the divisions between the lobes being rounded. The leaves are dark green on the upper surface, lighter green beneath, turning in autumn to brilliant shades of dark red, scarlet, orange and clear yellow.

The _flowers_ are yellowish-green, on long threadlike stalks, appearing with the leaves, the two kinds in separate clusters. The _fruit_, which ripens in the fall, consists of a two-winged "samara", or "key", the two wings nearly parallel, each about 1 inch in length and containing a seed. It is easily carried by the wind.

The _wood_ is hard, heavy, strong, close-grained and light brown in color. It is known, commercially as hard maple, and is used in the manufacture of flooring, furniture, shoe-lasts and a great variety of novelties.

The black maple, _Acer nigrum_ Michx., occurs with the sugar maple with darker bark. The leaves are usually wider than long, yellow-green and downy beneath, and the base of the petioles enlarged. The two lower lobes are very small; the lobes are undulate or entire.

+SILVER MAPLE+ _Acer saccharinum_ L.

THE silver or river maple, also called the soft maple, occurs on moist land and along streams. It attains heights of 100 feet or more and diameters of 3 feet or over. It usually has a short trunk which divides into a number of large ascending limbs. These again subdivide, and the branches droop but turn upward at the tips. The _bark_ on the old stems is dark gray and broken into long flakes or scales; on the young shoots it is smooth and varies in color from reddish to a yellowish-gray. The silver maple grows rapidly and has been much planted as a shade tree. Because of the brittleness of its wood, it is often damaged by summer storms and winter sleet.

The _leaves_ are opposite on the stem, have from 3 to 5 lobes ending in long points with toothed edges and are separated by deep angular sinuses or openings; they are pale green on the upper surface and silvery-white underneath. The buds are rounded, red or reddish-brown, blunt-pointed; generally like those of red maple.

The _flowers_ appear in the spring before the leaves, in dense clusters, and are of a greenish-yellow color. The _fruit_ ripens in late spring. It consists of a pair of winged seeds or "keys" with wings 1 to 2 inches long on slender, flexible, threadlike stems about an inch long.

The _wood_ is soft, weak, even-textured, rather brittle, easily worked, and decays readily when exposed. It is considerably used for boxboards, furniture, veneers and fuel.

The red maple, or swamp maple, _Acer rubrum_ L., has leaves deeply lobed with the lobes sharply toothed. The autumn color is deep red. The flowers also are red and the fruit is small reddish, maturing late in spring.

+BOX ELDER+ _Acer negundo_ L.

THE box elder is a fairly rapidly growing tree, found commonly along streams rather generally over the State. It is a tree of medium size, rarely reaching over 24 inches in diameter and 60 to 70 feet in height. It has been considerably planted for shade because in good soil its growth is rapid. Its limbs and branches, however, are fragile, and the tree as a whole is rather subject to disease. It is not long-lived or generally satisfactory for any purpose. It is prolific in reproduction but is largely destroyed by grazing and cultivation.

The _bark_ on young branches is smooth and green to purple in color; on old trees it is thin, grayish to light brown and deeply divided.

The _leaves_ are compound, with usually 3 leaflets (rarely 5 or 7), opposite, smooth and lustrous, green, and borne on a leaf stem or petiole 2 to 3 inches long. The leaflets are 2 to 4 inches long by 1 to 2 inches wide, making the whole leaf 5 to 8 inches in length.

The _fruit_ is a samara, or key, winged similarly to that of a sugar maple, but smaller. It ripens in late summer or early fall, and so is like its close relative, the sugar maple, but unlike its close relatives, the red maple and silver maple.

The _wood_ is soft, light, weak, close-grained and decays readily in contact with heat and moisture. It is used occasionally for fuel.

The Norway maple, _Acer platanoides_ L., is a European species which has been extensively planted. It forms a round, spreading crown of stout branches with coarse twigs. The leaves resemble those of the sugar maple but somewhat broader and the petioles exude a milky juice when cut. The flowers are larger than those of our native maples and fruit is large with diverging wings. It holds its leaves longer in the fall and the autumn coloring is pale yellow. It succeeds well as a city shade tree.

+OHIO BUCKEYE+ _Aesculus glabra_ Willd.

THE buckeye is rare in the northern fourth of Illinois, but is known in the rest of the State, forming no considerable part of the forest stand. It reaches a height of 60 to 70 feet and a diameter of 18 to 24 inches. The trunk is usually short, limby, and knotty. The crown or head, is generally open and made up of small spreading branches and twigs orange-brown to reddish-brown in color. The _bark_ is light gray and, on old trees, divided or broken into flat scales, which make the stem of the tree rough; the bark is ill-smelling when bruised.

The _leaves_ are opposite on the twigs, compound and consisting of 5 long-oval, rarely 7, pointed, toothed, yellow-green leaflets, set like the fingers of a hand at the top of slender petioles 4 to 6 inches long. They usually turn yellow and then fall early in the autumn.

The _flowers_ appear after the leaves unfold; are cream-colored; in terminal panicles 5 to 7 inches long and 2 to 3 inches broad, quite downy.

The _fruit_ is a thick, leathery, prickly capsule about an inch in diameter, and, breaking into 2 or 3 valves, discloses the bright, shiny, mahogany colored seeds, or nuts.

The _wood_ is light, soft and weak, and decays rapidly when exposed. It is used for woodenware, artificial limbs, paper pulp, and for lumber and fuel.

The horse-chestnut, _Aesculus hippocastanum_ L., is a handsome European tree with a very symmetrical crown. The flowers are larger than those of our native species and add beauty to the foliage. It forms a desirable shade tree.

+BASSWOOD+ _Tilia americana_ L.

THE basswood, or American linden, is a rather tall tree with a broad, round-topped crown. It ranges throughout Illinois and may be found wherever rich, wooded slopes, moist stream banks and cool ravines occur. It grows best in river bottoms, where it is common and forms a valuable timber tree, attaining a height of 80 feet and a diameter of 4 feet. The _bark_ is light brown, deeply furrowed and the inner bark furnishes bast for making mats.

The _leaves_ are broadly heart-shaped, 3 to 6 inches long, coarsely saw-toothed, smooth on both sides, except for some hairs on the axils of the veins. They are dark above but light green beneath.

The _flowers_ are yellowish-white, in drooping clusters opening in early summer, and flower stem is united to the middle of a long narrow leaf-like bract. They are very fragrant and from them the bees make a large amount of choice grade honey.

The _fruit_ is a berry-like, dry, 1 or 2 seeded, rounded nutlet 1/4 to 1/2 an inch in diameter, covered with short, thick and brownish wool. It remains attached in clusters to the leafy bract, which later acts as a wing to bear it away on the wind.

The _wood_ is light, soft, tough, not durable, light brown in color. It is used in the manufacture of pulp, woodenware, furniture, trunks, excelsior and many other articles.

It makes a fine shade tree, grows rapidly and is easily transplanted.

The white basswood, _Tilia heterophylla_ Vent., is similar to the preceding species, but with somewhat lighter bark. The leaves are larger, dark yellow-green above, the under surface being generally densely covered with short, silvery or gray hairs with tufts of brown hairs in the axils of the veins. It is more plentiful in the southern part of the State.

+FLOWERING DOGWOOD+ _Cornus florida_ L.

THE flowering dogwood is rare in the northern third of the State. It is a small tree, growing under the larger forest trees, usually 15 to 30 feet in height and 6 to 12 inches in diameter, with a rather flat and spreading crown and short, often crooked trunk. The _bark_ is reddish-brown to black and broken up into small 4-sided scaly blocks.

The _leaves_ are opposite, ovate, 3 to 5 inches long, 2 to 3 inches wide, pointed, entire or wavy on the margin, bright green above, pale green or grayish beneath.

The _flowers_, which unfold from the conspicuous round, grayish, winter flower buds before the leaves come out, are small greenish-yellow, arranged in dense heads surrounded by large white or rarely pinkish petal-like bracts, which give the appearance of large spreading flowers 2 to 4 inches across.

The _fruit_ is a bright scarlet "berry", 1/2 inch long and containing a hard nutlet in which are 1 or 2 seeds. Usually several fruits, or "berries", are contained in one head. They are relished by birds, squirrels and other animals.

The _wood_ is hard, heavy, strong, very close-grained, brown to red in color. It is in great demand for cotton-mill machinery, turnery handles and forms. One other tree has quite similar wood--the persimmon.

The dogwood, with its masses of early spring flowers, its dark red autumn foliage and its bright red berries, is probably our most ornamental native tree. It should be used much more extensively in roadside and ornamental planting.

The alternate-leaved dogwood, _Cornus alternifolia_ L., occasionally reaches tree size with long slender branches arranged in irregular whorls giving the tree a storied effect. The flowers are small, followed by blue-black fruit borne in loose red-stemmed clusters.

+SOUR GUM+ _Nyssa sylvatica_ Marsh.

THE sour gum, often called black gum, is found in many types of soil and in most conditions of soil moisture in southern Illinois, but it becomes rare in the northern half of the State. In lowlands, it is occasionally found in year-round swamps with cypress, and in the hills on dry slopes with oaks and hickories.

The _leaves_ are simple, 2 to 3 inches long, entire, often broader near the apex, shiny, dark green in color. In the fall the leaves turn a most brilliant red.

The _bark_ on younger trees is furrowed between flat ridges, and gradually develops into quadrangular blocks that are dense, hard and nearly black. Most of the branches are nearly horizontal.

The greenish _flowers_ on long slender stems appear in early spring when the leaves are about one-third grown. They are usually of two kinds, the male in many-flowered heads and the female in two to several-flowered clusters on different trees. The _fruit_ is a dark blue, fleshy berry, 2/3 of an inch long, containing a single hard-shelled seed, and is borne on long stems, 2 to 3 in a cluster.

The _wood_ is very tough, cross-grained, not durable in contact with the soil, hard to work, and warps easily. It is used for crate and basket veneers, box shooks, rollers, mallets, rough floors, mine trams, pulpwood and fuel.

The tupelo gum, or cotton gum, _Nyssa aquatica_ L., is found in deep river swamps which are flooded during a part of the year. It occurs in 4 or 5 of the southern counties of Illinois in cypress swamps. The enlarged base and the larger fruit serve to distinguish it from the sour gum. This fruit or "plum" is about an inch long, dark purple and has a tough skin enclosing a flattened stone. The wood is light, soft, and not strong and is used for woodenware, handles, fruit and vegetable packages.

+PERSIMMON+ _Diospyros virginiana_ L.

THE persimmon, often called "simmon", is well known throughout its range. It is a small tree, rarely exceeding 50 feet in height and 1 inch in diameter, occurring throughout the State from the southern part north to Peoria County. It seems to prefer dry, open situations, and is most abundant in the old fields, though it also occurs on rich bottom lands. The _bark_ of old trees is almost black and separated into thick nearly square blocks, much like the black gum.

The _leaves_ are alternate, oval, entire, 4 to 6 inches long, dark green and shining above, paler beneath.

The small _flowers_, which appear in May, are yellowish or creamy white, somewhat bell-shaped, the two kinds occurring on separate trees; the male in clusters of 2 or 3, the female solitary. They are visited by many insects.

The _fruit_ is a pulpy, round, orange-colored or brown berry, an inch or more in diameter and containing several flattened, hard, smooth seeds. It is strongly astringent while green, but quite sweet and delicious when thoroughly ripe.

The _wood_ is hard, dense, heavy, strong, the heartwood brown or black, the wide sapwood white or yellowish. It is particularly valued for shuttles, golf-stick heads, and similar special uses, but is not of sufficient commercial use to warrant its general encouragement as a timber tree.

The Hercules' club, _Aralia spinosa_ L., grows to tree size in southern Illinois, with a spiny stem 25 to 30 feet tall and a flat-topped head. The doubly compound leaves are often more than 3 feet long. Its small greenish-white flowers are followed by large clusters of purple juicy berries. It is desirable for ornamental planting.

+WHITE ASH+ _Fraxinus americana_ L.

THE white ash is found throughout the State, but grows to best advantage in the rich moist soils of bottom lands. It reaches an average height of 50 to 80 feet and a diameter of 2 to 3 feet, though much larger trees are found in virgin forests. The _bark_ varies in color from a light gray to a gray-brown. The rather narrow ridges are separated with marked regularity by deep, diamond-shaped fissures.

The opposite _leaves_ of the white ash are from 8 to 12 inches long and have from 5 to 9 plainly stalked, sharp-pointed leaflets, dark green and smooth above, pale green beneath.

The _flowers_ are of two kinds on different trees, the staminate in dense reddish-purple clusters and the pistillate in more open bunches. The _fruit_ of the ash is winged, 1 to 1-1/2 inches long, resembling the blade of a canoe paddle in outline, with the seed at the handle end. The fruits mature in late summer and are distributed effectively by the winds.

The _wood_ of the white ash is extremely valuable on account of its toughness and elasticity. It is preferred to all other native woods for small tool handles, such athletic implements as rackets, bats, and oars, and agricultural implements. It is also used extensively for furniture and interior finish.

The green ash, _Fraxinus pennsylvanica lanceolata_ Sarg., is common in stream valleys throughout the State. The hairy form of this tree is known as the red ash. This species differs from the white ash in having the leaves bright green or yellow-green on both sides. The fruit has the wing portion extending well down past the middle of the seed-bearing part, and with the wing sometimes square or slightly notched at the outer end. The wood is similar to that of the white ash, but is not quite so tough.

+BLUE ASH+ _Fraxinus quadrangulata_ Michx.

THE blue ash is not very common but widely distributed in the upland portions of the State, where it is limited to limestone bluffs, occasionally descending to the adjacent bottom lands. It becomes a large tree 60 feet or more in height with a trunk 2 feet in diameter. The young twigs are usually square, sometimes winged or 4-ridged between the leaf bases.

The _bark_ is light gray tinged with red, 1/2 to 2/3 inch thick, irregularly divided into large plate-like scales. Macerating the inner bark in water yields a blue dye.

The _leaves_ are 8 to 12 inches long, having 7 to 11 stalked leaflets, long pointed and coarsely toothed, thick and firm, smooth and yellowish-green above, paler beneath.

The _flowers_ are without petals and appear in clusters when the buds begin to expand.

The _fruit_ is flattened and oblong, 1 to 2 inches long and less than 1/2 inch wide and usually notched at the outer end. The wing is about twice the length of the seed-bearing portion and extends down the sides past the middle.

The _wood_ is heavy, hard, and close-grained, light yellow, streaked with brown, with a very broad zone of lighter sapwood. It is not usually distinguished commercially from the wood of other ashes.

The pumpkin ash, _Fraxinus tomentosa_ Michx., grows in deep river swamps in southern Illinois. It is a tall slender tree, usually with a much enlarged base. The twigs are light gray. The leaves, with 7 to 9 leaflets, smooth above and soft downy below, are from 10 to 18 inches long.