Part 42
[6] This is a very large family, containing trees, shrubs, and vines, such as locusts, acacias, beans, and clovers. There are 430 genera in the world, and many times that many species. The United States has seventeen genera and thirty species of the pea family that are large enough to be classed as trees. Their common names follow: Florida Cat’s Claw, Huajillo, Texan Ebony, Wild Tamarind, Huisache, Texas Cat’s Claw, Devil’s Claw, Leucæna, Chalky Leucæna, Screwbean, Mesquite, Redbud, Texas Redbud, Honey Locust, Water Locust, Coffeetree, Horsebean, Small-leaf Horsebean, Greenbark Acacia, Palo Verde, Frijolito, Sophora, Yellow-wood, Eysenhardtia, Indigo Thorn, Locust, New Mexican Locust, Clammy Locust, Sonora Ironwood, Jamaica Dogwood. These species are treated separately in the following pages, and are given space according to their relative commercial importance in the particular regions where they grow.
Several of the names refer to the color of the wood, and seem contradictory, for yellow, green, and red are not the same; yet the names describe with fair accuracy. Color of the heartwood varies with different trees, yellow with some, tinged with red with others, and sometimes it might be appropriately called blue locust, for the heartwood is nearer that color than any other.
The natural range of locust seems to have been confined to the Appalachian mountain ranges from Pennsylvania to Georgia. It probably existed as a low shrub in parts of Arkansas and Oklahoma. Its range has been extended by planting until it now reaches practically all the states, but is running wild in only about half of them. It has received a great deal of attention from foresters and tree planters. It attracted notice very early, because of its hardness, strength, and lasting properties. At one time the planting of locust came nearly being a fad. In England it was supposed that it would rise to great importance in shipbuilding, and in France it was looked upon as no less important. Books were written on the subject in both English and French. All the details of planting and utilization were discussed. Its generic name, _Robinia_, is in honor of a Frenchman, Robin. Extravagant claims were once made for the wood. When American ships were gaining victory after victory over English vessels in the war of 1812, it was asserted in England that the cause of American success was the locust timber in their ships. The claim may have been partly true, but other factors contributed to the phenomenal series of successes.
The locust craze died a natural death. Too much was claimed for the wood. Possibilities in the way of growth were over estimated. It was assumed that the tree, if planted, would grow everywhere as vigorously as on its native mountains in Pennsylvania, Maryland, and Virginia, where trees two or three feet in diameter and eighty feet high were found. Experience proved later that nature had planted the locust in the best place for it, and when transplanted elsewhere it was apt to fall short of expectations. Outside of its natural range it grows vigorously for a time, and occasionally reaches large size; but in recent years the locust borer has defeated the efforts of man to extend the range of this species and make it profitable in regions distant from its native home. The tree is often devoured piecemeal, branches and twigs breaking and falling, and trunks gradually disappearing beneath the attacks of the hungry borers. No effective method of combating the pest is known. The planting of locust trees, once so common, has now nearly ceased.
Within its native range, and beyond that range when it has a chance, locust is a valuable and beautiful tree. It is valuable at all times on account of the superior wood which it furnishes, and beautiful when in bloom and in leaf. A locust in full flower is not surpassed in ornamental qualities by any tree of this country. It is a mass of white, exceedingly rich in perfume. It blooms in May or June. During the summer its foliage shows tropical luxuriance with exquisite grace. Its compound leaves are from eight to fourteen inches long, with seven to nine leaflets. They come late in spring and go early in autumn. The tree’s thorns, resembling cat claws, are affixed to the bark only, and usually fall with the leaves. The fruit is a pod three or four inches long, and contains four or eight wingless seeds. They depend on animals to carry them to planting places. The pods dry on the branches, and rattle in the wind most of the autumn. The tree spreads by underground roots which send up sprouts. A locust in winter is not a thing of beauty. It appears to be dead; not a bud visible. Its black, angular branches lack every line of grace.
Locust wood is remarkable for strength, hardness, and durability. It is about one pound per cubic foot lighter than white oak, but is thirty-four per cent stiffer and forty-five per cent stronger. Its strength exceeds that of shagbark hickory, and it is doubtful whether a stronger wood exists in the United States. Its hardness is equally remarkable, and is said to be due to crystals formed in the wood cells, and known as “rhaphides.” Its durability is probably equal to that of Osage orange, mesquite, and catalpa, but it is not easy to fix a standard of durability by which to compare different woods. Locust is the best fence post wood in this country, because it is usually much straighter than other very durable woods. The posts are expected to last at least thirty years, and have been known to stand twice that long.
For more than 150 years locust was almost indispensable in shipbuilding, furnishing the tree nails or large pins which held the timbers together. It supplied material for other parts of ships also, but in smaller quantities. The substitution of steel ships for wooden lessened demand for locust pins, and in many instances large iron nails are used to fasten timbers together. In spite of this, the demand for locust tree nails is nearly always ahead of supply.
The wood’s figure is fairly strong, due to the contrast between the springwood and that grown later, but not to the medullary rays, which are small and inconspicuous. The wood is not in much demand for ornamental purposes. Small amounts are made into policemen’s clubs, rake teeth, hubs for buggy wheels, ladder rungs, and tool handles.
The tree grows rapidly where conditions are favorable, and very slowly when they are not. Usually trees of fence post size are twenty years old at least, but trunks thirty five years old have been known to produce a post for each two years of age, though that was exceptional. Railroads, especially in Pennsylvania, planted locust largely a few years ago for ties. It has been reported that in some instances expectations of growth have not been fully realized.
CLAMMY LOCUST (_Robinia viscosa_) was originally confined to the mountains of North Carolina and South Carolina where its attractive flowers brought it to the notice of nurserymen who have enlarged its natural range a hundred if not a thousand fold. It is now grown in parks and gardens not only in the United States east of the Mississippi river and as far north as Massachusetts, but in most foreign countries that have temperate climates. It is usually a shrub, but on some of the North Carolina mountains it attains a height of forty feet and a diameter of twelve inches. The wood is seldom or never used for any commercial purpose. The leaves are from seven to twelve inches long, and contain thirteen to twenty-one leaflets. The flowers appear in June, possess little odor, and are admired solely for their beauty. They are mingled red and rose color. The pods are from two to three and a half inches long, and contain small, mottled seeds. The wood is hard and heavy, the heart brown and the sap yellow. In its wild haunts it is usually a shrub five or six feet high.
NEW MEXICAN LOCUST (_Robinia neo-mexicana_) is a small southwestern tree, seldom exceeding a height of twenty-five feet or a diameter of eight inches. It ranges from Colorado to Arizona, and takes its name from its presence in New Mexico. It reaches its largest size near Trinidad, Colorado. It is found at elevations of 7,000 feet. Leaves are from six to twelve inches long, and the leaflets number from fifteen to twenty-one. The flowers appear in May and are less showy than those of the eastern locust. The wood is heavy, exceedingly hard, the heartwood yellow, streaked with brown, the thin sapwood light yellow. This locust is occasionally used locally for small posts or stakes, but is generally too small. It is sometimes met with in cultivation in Europe and the eastern states.
TEXAN EBONY (_Zygia flexicaulis_) ranges from the Texas coast through Mexico to Lower California. It reaches a height of thirty feet or more, and a diameter of two or less. It is a beautiful tree along the lower Rio Grande where it reaches its largest size. The light yellow or cream-colored, very fragrant flowers bloom from June till August; the fruit ripens in Autumn but adheres several months to the branches. Mexicans roast the seeds as a substitute for coffee. The color of the heartwood gives this tree its name, but it is not a true ebony. The wood of the roots is blacker than that of the trunk, and small articles made of roots resemble black ebony of Ceylon. The trunk wood is liable to be streaked with black, brown, and medium yellow. The rings of annual growth are frequently of different colors. Considerable demand is made upon this wood in Texas for crossties. It is very durable, but is so hard that holes must be bored for the spikes. It is sold in large amounts as cordwood, and it burns well. Other articles made of this so-called ebony are foundation blocks for buildings and rollers for moving houses. It is used also for small turnery.
HUAJILLO (_Zygia brevifolia_) has no English name, but Americans in the Rio Grande valley where this tree grows call it by its Mexican name. It is a larger tree in Mexico than on this side of the river. It is not often more than thirty feet high and six inches in diameter, and is generally a shrub. Its beautiful foliage looks like masses of ferns, and the flowers range from white to violet-yellow. The wood is dark, hard, heavy, and is seldom used for anything but fuel.
FLORIDA CAT’S CLAW (_Zygia unguis-cati_), with a Latin name that would make Julius Caesar stare and gasp, reaches its largest size in the United States on Elliott’s Key, Florida. Its name refers to its curved thorns. Trunks twenty-five feet high and eight inches in diameter are the largest in this country. It bears pods, but the leaves are not compound, thus differing from most trees of the pea family. The wood is not put to any use, though it is very hard and heavy, rich red, varying to purple, with clear yellow sapwood. It is said to check badly in drying. The bark is used for medicine in some of the islands of the West Indies.
[Illustration]
HONEY LOCUST
[Illustration: HONEY LOCUST]
HONEY LOCUST
(_Gleditsia Triacanthos_)
This tree has never suffered for want of names, but most of them refer either to the sweetness of the pod or to the fierceness of the thorns. The belief has long prevailed that it was the pods of this tree on which John the Baptist fed while a recluse in the Syrian desert. The tradition should not be taken seriously. It was certainly not this tree, if any, which furnished food to the prophet in the wilderness, for it does not grow in Syria. Some related species may grow there, for species of _Gleditsia_ occur in western Asia as well as in China, Japan, and west Africa. The generic name is in honor of Johann Gottlieb Gleditsch, a German botanist who died in 1786.
The name honey locust refers to the pod, not the flowers. The latter are greenish, inconspicuous, and though eagerly sought by bees, they offer no particular attractions to people. Few persons ever notice them.
In some of the southwestern states the tree is called black locust, though for what reason it is not apparent. Sweet locust, by which name it is known in several states, has reference to the pods, as do the names honey, and honey-shucks locust, applied in different localities. Many persons in naming the tree have thorns in mind. It is known as three-thorned acacia, thorn locust, thorn tree, thorny locust, and thorny acacia. The botanist who named it considered thorns a characteristic, for _Triacanthos_ means “three-thorned.”
No one who has ever had dealings with the thorns, will fail to duly consider them. They are about the most ferocious product of American forests. The tree’s trunk and largest branches bristle with them, standing out like porcupine quills, and sharper than any needle devised by human ingenuity. Microscopists use them for picking up and handling minute objects, their points being smooth and delicate though their shafts may be strong and rough. Thorns are arrested branches, coming from deep down in the wood. No more can one of them be pulled out than a limb can be extracted by the roots. They come from the center of the tree or limb. Some put out leaves and become true branches, but others sharpen their points, assume an attitude of hostility, and remain thorns to the end of their lives. Some of them are a foot long, and are so strong that birds flying against them are impaled and meet cruel death. A well-armed trunk is proof against the agility and skill of the squirrel. He cannot negotiate the thorns, and probably he tries only once. The hot pursuit of a dog will not compel him to attempt it. All trees, however, are not formidably thorned; some have few, and certain varieties have none.
The honey locust is sometimes called the Confederate pin tree in the South. This is a reference to the Civil war, and the use occasionally made of the thorns by soldiers in mending the rents in their torn uniforms. The thorns were once put to a somewhat similar use among the Alleghany mountains where local factories for carding and spinning country wool employed them to pin up the mouths of wool sacks.
The natural range of honey locust has been greatly extended by man. It was not originally found east of the Alleghany mountains. It grew from western Pennsylvania to northern Alabama and Mississippi, and westward to Nebraska and Texas. It is now naturalized east of the Alleghanies, and southward to the Gulf of Mexico. Planting for ornamental purposes and for hedges has been the cause of its extension into new territory. In spite of thorns, it is ornamental. Its foliage is thin, and its flowers inconspicuous, but the tree possesses a grace which wins it favor. It grows very rapidly, and in a short time a seedling becomes a respectable tree, and continues its rapid growth a long time. In southern Indiana and Illinois, which is the best part of its range, trees have attained a height of 140 feet and a diameter of six. The average size of forest-grown specimens is seventy-five feet in height, and two or more in diameter.
The leaves are seven or eight inches long, doubly compound; the fruit a pod a foot or more in length, which assumes a twist when ripe, or sometimes warps several ways. The green pod contains a sweet substance often eaten by children, but it is believed to be of little value for human food. Cattle devour the pods when in the sugary condition; but they cannot often obtain them, because thorns intervene, when the pods would otherwise be in reach. In rural districts, a domestic beer is brewed from the young fruit. The juice extracted from it is permitted to ferment, but the beverage is probably never sold in the market.
The pods are in no hurry to let go and fall, even after they are fully ripe. They become dry, distort themselves with a number of corkscrew twists, and hang until late fall or early winter, rattling in the wind and occasionally shaking out a seed or two.
Honey locust has never been considered important from the lumberman’s standpoint. Sawlogs go to mills here and there, but never many in one place. The wood is not listed under its own name, but is put in with something else. Occasionally, it is said, it passes as sycamore in the furniture factory, though the difference ought not be difficult to detect. It doubtless depends to a considerable degree on the particular wood, for all honey locust does not look alike when converted into lumber. Some of that in the lower Mississippi valley might pass as sycamore if inspection is not too conscientiously carried out. The medullary rays, being darker than the body of the wood, suggest sycamore in quarter-sawed stock. Some of it goes into furniture, finish, balusters, newel posts, panels, and molding, particularly in eastern Texas. In Louisiana, where wood of similar texture and appearance might be expected, it is not looked on with favor, but is employed only in the cheapest, roughest work.
The principal use of the wood is for posts and railroad ties. It lasts well, and is strong. Claims have been made that it is generally equal and in some ways superior to locust. It is difficult to see on what these claims are based. It is lighter, less elastic, and much weaker. Figures showing the comparative durability of the two woods are not available, but in like situations, locust would doubtless last much longer. As timber trees, the former may have the advantage over locust in being free from attacks of borers, attaining greater size, and thriving in a much larger area. It has been planted for ornament in other lands than this, and is now prospering in all the important countries of the temperate zone. One variety is thornless, and is known to botanists as _Gleditsia triacanthos lævis_; another has short thorns.
WATER LOCUST (_Gleditsia aquatica_) looks so much like honey locust that the two are often supposed to be the same species in Louisiana; yet there are a number of differences. Water locust has fewer thorns and they are smaller, and often flat like a knife blade. The pods are entirely different from those of honey locust, being short and wide. The two species share the same range to some extent, but that of water locust is smaller, extending from South Carolina to Texas, Illinois, and Missouri; but the best of the species is west of the lower Mississippi where trees may reach a height of sixty feet and a diameter of two. The wood is heavy, hard, and strong, the heartwood rich bright brown, tinged with red, the sapwood yellow. The wood is much like that of honey locust, and when used at all is employed in the same way.
TEXAS LOCUST (_Gleditsia texana_) is of no importance as a timber tree, and deserves mention only because its extremely restricted range gives it an interest. It exists, as far as known, in a single grove on the bottom lands of the Brazos river, near Brazoria, Texas, where some of the trees exceed 100 feet in height, and a diameter of two. The bark is smooth and thin, the leaves resemble those of honey locust, and the pods are about one-third as long.
HUISACHE (_Acacia farnesiana_) is native along the Rio Grande in Texas, but it is running wild in Florida from planted trees. It is one of the most widely distributed species in the world, both by natural dispersal and by planting; and it is one of the handsomest members of the large group of acacias which includes more than 400 species. It bears delicate double-compound leaves, small and graceful. A tree in full leaf in its native wilds along the Rio Grande looks like a trembling fluffy mass of green silk. Nature formed the tree for ornament, not for timber. It attains a height of from twenty to forty feet, diameter eighteen inches or less. Trunk usually divides into several branches near the ground. Perhaps the only place in this country where the wood is used is in southern Texas where is it called “cassie,” a shortening of acacia. The wood so much resembles mesquite that locally they are considered the same. Huisache warps and checks in seasoning, but it is employed in a small way for furniture, usually as small table legs, spindles, knobs, and ornaments. It takes high polish, and resembles the best grades of black walnut, but is much heavier, harder, and stronger. It is next to impossible to drive a nail into it without first boring a hole. When used as crossties, holes must be bored for the spikes. The heartwood resists decay a long time, but the thin sapwood is liable to be riddled by small boring insects, which seldom or never enter the heartwood.
TEXAS CAT’S CLAW (_Acacia wrightii_) is a hardluck tree of western Texas where it is usually found on dry, gravelly hills and in stony ravines. Its twice-compound leaves are among the smallest of the acacias, seldom exceeding two inches in length. The fragrant, light yellow flowers appear from March to May, and the short pods ripen in midsummer, but like so many trees of the pea family, they are in no hurry to fall. The largest trees are thirty feet high and one in diameter, but most people associate cat’s claw with low, tangled brush, tough as wire, and armed with curved thorns so strong that their hold on clothing can hardly be broken. When a cat’s claw bush strikes out to become a tree--which is infrequent--it grows rapidly. It has been known to attain a diameter of nine inches in twenty-three years. The heart is dark in color and exceedingly hard. The color varies from nearly red to nearly black, and takes a polish almost like ivory. The thin yellow sapwood is preyed on by boring insects. Heartwood is made into canes, umbrella sticks, tool handles, rulers, and turned novelties.
DEVIL’S CLAW (_Acacia greggii_) has such paradoxical names as paradise flower, ramshorn, and cat’s claw. It deserves them all where it grows wild on the semi-deserts of the Southwest from Texas to California. The double-compound leaves are one or two inches long, its bright, creamy-yellow and exquisitely fragrant flowers are the glory of desert places, while its masses of thorns readily suggest the common name by which it is known. The wood is scarce, but extraordinarily fine. It is dark rich red, but clouded with streaks and patches of other shades, becoming at times gray, at others green. No nail can be driven into it, and an ordinary gimlet will hardly bore it. It is so saturated with oil that it is greasy to the touch. It is manufactured into small articles, but apparently is not used outside of the locality where it grows. The wood is often contorted, due to pits and cavities which slowly close as the tree advances in age. They add to rather than detract from the wood’s beauty.
[Illustration]
COFFEE TREE
[Illustration: COFFEE TREE]
COFFEETREE
(_Gymnocladus Dioicus_)
This tree is scarce though its range covers several hundred thousand square miles, from New York to Minnesota, and from Tennessee to Oklahoma. It never occurs in thick stands, and usually the trees are widely scattered. Many districts of large size within the limits of its range appear to have none.