"Trees are God's Architecture."—Anonymous.

"A Student who has learned to observe and describe so simple a matter as the form of a leaf has gained a power which will be of lifetime value, whatever may be his sphere of professional employment."—Wm. North Rice.

PREFACE.

This book has been prepared with the idea that teachers generally would be glad to introduce into their classes work dealing with the real objects of nature, provided the work chosen were of a character that would admit of its being studied at all seasons and in all localities, and that the subject were one of general interest, and one that could be taught successfully by those who have had no regular scientific instruction.

The trees of our forests, lawns, yards, orchards, streets, borders, and parks give us just such a department. Though many consider a large part of the vegetable kingdom of little importance, and unworthy of any serious study, there are few who do not admire, and fewer still who do not desire to know, our trees, the monarchs of all living things.

The difficulty in tree study by the aid of the usual botanies lies mainly in the fact that in using them the first essential parts to be examined are the blossoms and their organs. These remain on the trees a very short time, are often entirely unnoticed on account of their small size or obscure color, and are usually inaccessible even if seen. In this book the leaves, the wood, the bark, and, in an elementary way, the fruit are the parts to which the attention is directed; these all can be found and studied throughout the greater part of the year, and are just the parts that must be thoroughly known by all who wish to learn to recognize trees.

Though every teacher is at liberty to use the book as he thinks best, the author, who has been a class teacher for over twenty years, is of the opinion that but little of Part I. need be thoroughly studied and recited, with the exception of Chapter III. on leaves. The object of this chapter is not to have the definitions recited (the recitation of definitions in school work is often useless or worse than useless), but to teach the pupil to use the terms properly and to make them a portion of his vocabulary. The figures on pages 38-43 are designed for class description, and for the application of botanical words. The first time the chapter is studied the figure illustrating the term should be pointed out by the pupil; then, as a review of the whole chapter, the student should be required to give a full description of each leaf.

After this work with Chapter III., and the careful reading of the whole of Part I., the pupils can begin the description of trees, and, as the botanical words are needed, search can be made for them under the proper heads or in the Glossary.

The Keys are for the use of those who know nothing of scientific botany. The advanced botanist may think them too artificial and easy; but let him remember that this work was written for the average teacher who has had no strictly scientific training. We can hardly expect that the great majority of people will ever become scientific in any line, but it is possible for nearly every one to become interested in and fully acquainted with the trees of his neighborhood.

The attainment of such botanical knowledge by the plan given in this volume will not only accomplish this useful purpose, but will do what is worth far more to the student, i.e., teach him to employ his own senses in the investigation of natural objects, and to use his own powers of language in their description.

With hardly an exception, the illustrations in the work are taken from original drawings from nature by the author. A few of the scales of pine-cones were copied from London's "Encyclopædia of Trees"; some of the Retinospora cones were taken from the "Gardener's Chronicle"; and three of the illustrations in Part I. are from Professor Gray's works.

The size of the illustration as compared with the specimen of plant is indicated by a fraction near it; ¼ indicates that the drawing is one fourth as long as the original, 1/1 that it is natural size, etc. The notching of the margin is reduced to the same extent; so a margin which in the engraving looks about entire, might in the leaf be quite distinctly serrate. The only cases in which the scale is not given are in the cross-sections of the leaves among the figures of coniferous plants. These are uniformly three times the natural size, except the section of Araucaria imbricata, which is not increased in scale.

The author has drawn from every available source of information, and in the description of many of the species no attempt whatever has been made to change the excellent wording of such authors as Gray, Loudon, etc.

The ground covered by the book is that of the wild and cultivated trees found east of the Rocky Mountains, and north of the southern boundary of Virginia and Missouri. It contains not only the native species, but all those that are successfully cultivated in the whole region; thus including all the species of Ontario, Quebec, etc., on the north, and many species, both wild and cultivated, of the Southern States and the Pacific coast. In fact, the work will be found to contain so large a proportion of the trees of the Southern States as to make it very useful in the schools of that section.

Many shrubby plants are introduced; some because they occasionally grow quite tree-like, others because they can readily be trimmed into tree-forms, others because they grow very tall, and still others because they are trees in the Southern States.

In nomenclature a conservative course has been adopted. The most extensively used text-book on the subject of Botany, "Gray's Manual," has recently been rewritten. That work includes every species, native and naturalized, of the region covered by this book, and the names as given in that edition have been used in all cases.

Scientific names are marked so as to indicate the pronunciation. The vowel of the accented syllable is marked by the grave accent (`) if long, and by the acute (´) if short.

In the preparation of this book the author has received much valuable aid. His thanks are especially due to the authorities of the Arnold Arboretum, Boston, Massachusetts, and of the Missouri Botanical Garden, St. Louis, for information in regard to the hardiness of species; to Mr. John H. Redfield, of the Botanical Department of the Philadelphia Academy of Natural Sciences, for books, specimens from which to make illustrations, etc.; and to Dr. A. C. Stokes, of Trenton, New Jersey, for assistance in many ways, but especially for the accurate manner in which he has inked the illustrations from the author's pencil-drawings.

The author also wishes to acknowledge the help received from many nurserymen in gathering specimens for illustration and in giving information of great value. Among these, special thanks are due to Mr. Samuel C. Moon, of Morrisville Nurseries, who placed his large collection of living specimens at the author's disposal, and in many other ways gave him much intelligent aid.

CONTENTS.

TREES.

PART I.

THE ESSENTIAL ORGANS, AND THE TERMS NEEDED FOR THEIR DESCRIPTION.

Chapter I.

Roots.

Trees with large tap-roots are very hard to transplant, and cannot with safety be transferred after they have attained any real size. The Hickories and Oaks belong to this class.

Trees having multiple roots are readily transplanted, even when large. The Maples and Elms are of this class.

Roots that grow from the root-end of the embryo of the seed are called primary roots; those growing from slips or from stems anywhere are secondary roots.

Some trees grow luxuriantly with only secondary roots; such trees can readily be raised from stems placed in the ground. The Willows and Poplars are good examples of this group. Other trees need all the strength that primary roots can give them; these have to be raised from seed. Peach-trees are specially good examples, but practically most trees are best raised from seed.

A few trees can be easily raised from root-cuttings or from suckers which grow up from roots. The Ailanthus, or "Tree of Heaven," is best raised in this way. Of this tree there are three kinds, two of which have disagreeable odors when in bloom, but the other is nearly odorless. By using the roots or the suckers of the third kind, only those which would be pleasant to have in a neighborhood would be obtained. One of the large cities of the United States has in its streets thousands of the most displeasing of these varieties and but few of the right sort, all because the nurseryman who originally supplied the city used root-cuttings from the disagreeable kind.

If such trees were raised from the seed, only about one third would be desirable, and their character could be determined only when they had reached such a size as to produce fruit, when it would be too late to transplant them. Fruit-trees, when raised from the seed, have to be grafted with the desired variety in order to secure good fruit when they reach the bearing age.

Chapter II.
Stems and Branches.

The stem is the distinguishing characteristic of trees, separating them from all other groups of plants. Although in the region covered by this book the trees include all the very large plants, size alone does not make a tree.

A plant with a single trunk of woody structure that does not branch for some distance above the ground, is called a tree. Woody plants that branch directly above the soil, even though they grow to the height of twenty feet or more, are called shrubs, or, in popular language, bushes. Many plants which have a tendency to grow into the form of shrubs may, by pruning, be forced to grow tree-like; some that are shrubs in the northern States are trees further south.

All the trees that grow wild, or can be cultivated out of doors, in the northern States belong to one class, the stems having a separable bark on the outside, a minute stem of pith in the center, and, between these, wood in annual layers. Such a stem is called exogenous (outside-growing), because a new layer forms on the outside of the wood each year.

Another kind of tree-stem is found abundantly in the tropics; one, the Palmetto, grows from South Carolina to Florida. While in our region there are no trees of this character, there are plants having this kind of stem, the best illustration being the corn-stalk. In this case there is no separable bark, and the woody substance is in threads within the pithy material. In the corn-stalk the woody threads are not very numerous, and the pith is very abundant; in most of the tropical trees belonging to this group the threads of wood are so numerous as to make the material very durable and fit for furniture. A stem of this kind is called endogenous (inside-growing). Fig. 1 represents a longitudinal and a cross section of an exogenous stem, and Fig. 2 of an endogenous one.

Since all the stems with which we have to deal are exogens, a particular description of that class will here be given. Fig. 1 shows the appearance of a section of an Ash stem six years old. The central portion, which is about as thick as wrapping-twine, is the pith; from this outward toward the bark can be seen the six annual layers of the wood; and then comes the bark, consisting of two portions. First there is an inside layer of greenish material, the fresh-growing portion, and lastly the outer or dead matter. This outer portion must crack open, peel off, or in some way give a chance for the constant growth of the trunk. The different kinds of trees are readily known by the appearance of the bark of the trunk, due to the many varieties of surface caused by the allowance for growth. None of the characteristics of trees afford a better opportunity for careful observation and study than the outer bark.

The Birches have bark that peels off in thin horizontal layers—the color, thinness, and toughness differing in the different species; the Ashes have bark which opens in many irregular, netted cracks moderately near each other; the bark of the Chestnut opens in large longitudinal cracks quite distant from one another. The color of the bark and the character of the scales are quite different in the White and the Black Oaks.

In the woody portion radiating lines may be seen; these are the silver grain; they are called by the botanist medullary rays.

The central portion of the wood of many large stems is darker in color than the rest. This darker portion is dead wood, and is called heart-wood; the outer portion, called sap-wood, is used in carrying the sap during the growing season. The heart-wood of the Walnut-tree is very dark brown; that of the Cherry, light red; and that of the Holly, white and ivory-like. The heart-wood is the valuable part for lumber.

If examined under a magnifying glass, the annual layers will be seen to consist of minute tubes or cells. In most trees these tubes are much larger in the portion that grew early in the season, while the wood seems almost solid near the close of the annual layer; this is especially true in the Ashes and the Chestnut; some trees, however, show but little change in the size of the cells, the Beech being a good example. In a cross-section, the age of such trees as the Chestnut can readily be estimated, while in the Beech it is quite difficult to do this. Boxwood, changing least in the character of its structure, is the one always used for first-grade wood-engravings.

When wood is cut in the direction of the silver grain, or cut "quartering" as it is called by the lumbermen, the surface shows this cellular material spread out in strange blotches characteristic of the different kinds of wood. Fig. 16 shows an Oak where the blotches of medullary rays are large. In the Beech the blotches are smaller; in the Elm quite small. Lumber cut carefully in this way is said to be "quartered," and with most species its beauty is thereby much increased.

Any one who studies the matter carefully can become acquainted with all the useful and ornamental woods used in a region; the differences in the color of the heart-wood, the character of the annual layers, and the size and the distribution of the medullary rays, afford enough peculiarities to distinguish any one from all others.

Branching.—The regular place from which a branch grows is the axil of a leaf, from what is called an axillary bud; but branches cannot grow in the axils of all leaves. A tree with opposite leaves occasionally has opposite branches; while a tree with alternate leaves has all its branches alternate.

Most branches continue their growth year after year by the development of a bud at the end, called a terminal bud. Many trees form this bud for the next year's growth so early in the year that it is seldom or never killed by the winter weather; such trees grow very regularly and are symmetrical in form. Most evergreens are good examples. Fig. 3 represents a good specimen. The age of such trees, if not too great, can be readily ascertained by the regularity of each year's growth. The tree represented is sixteen years old. The branches that started the fifth year, about the age at which regular growth begins, are shown by their scars on the trunk.

The terminal buds of many trees are frequently killed by the frosts of winter; such trees continue their growth by the development of axillary buds; but as growth from an axillary bud instead of a terminal one will make a branch crooked, such trees are irregular in their branching and outline. Just which axillary buds are most apt to grow depends upon the kind of tree, but trees of the same variety are nearly uniform in this respect. Most trees are therefore readily recognized by the form of outline and the characteristic branching. A good example of a tree of very irregular growth is the Catalpa (Indian Bean), shown in Fig. 4. The tendency to grow irregularly usually increases with age. The Buttonwood, for example, grows quite regularly until it reaches the age of thirty to forty years; then its new branches grow in peculiarly irregular ways. The twigs of a very old and a young Apple-tree illustrate this change which age produces.

There are great differences in the color and surface of the bark of the twigs of different species of trees; some are green (Sassafras), some red (Peach, on the sunny side), some purple (Cherry). Some are smooth and dotless, some marked with dots (Birch), some roughened with corky ridges (Sweet Gum), etc.

The taste and odor of the bark are characteristics worthy of notice: the strong, fragrant odor of the Spice-bush; the fetid odor of the Papaw; the aromatic taste of the Sweet Birch; the bitter taste of the Peach; the mucilaginous Slippery Elm; the strong-scented, resinous, aromatic Walnut, etc.

The branches of trees vary greatly in the thickness of their tips and in their tendency to grow erect, horizontal, or drooping. Thus the delicate spray of the Birches contrasted with the stout twigs of the Ailanthus, or the drooping twigs of the Weeping Willow with the erect growth of the Lombardy Poplar, give contrasts of the strongest character. In the same way, the directions the main branches take in their growth from the trunk form another distinctive feature. Thus the upward sloping branches of the Elm form a striking contrast to the horizontal or downward sloping branches of the Sour Gum, or, better still, to certain varieties of Oaks.

When the main trunk of a tree extends upward through the head to the tip, as in Fig. 3, it is said to be excurrent. When it is soon lost in the division, as in Fig. 4, it is said to be deliquescent.

Chapter III.
Leaves.

Leaves are the lungs of plants. The food taken in by the roots has to pass through the stem to the leaves to be acted upon by the air, before it becomes sap and is fit to be used for the growth of the plant. No portion of a plant is more varied in parts, forms, surface, and duration than the leaf.

No one can become familiar with leaves, and appreciate their beauty and variety, who does not study them upon the plants themselves. This chapter therefore will be devoted mainly to the words needed for leaf description, together with their application.

The Leaf.—In the axil of the whole leaf the bud forms for the growth of a new branch. So by noting the position of the buds, all the parts included in a single leaf can be determined. As a general thing the leaf has but one blade, as in the Chestnut, Apple, Elm, etc.; yet the Horse-chestnut has 7 blades, the Common Locust often has 21, and a single leaf of the Honey-locust occasionally has as many as 300. Figs. 17-58 (Chapter VII.) are all illustrations of single leaves, except Fig. 43, where there are two leaves on a twig. A number of them show the bud by which the fact is determined (Figs. 25, 26, 31, 33, 34, 36, 40, etc.); others show branches which grew from the axillary buds, many of them fruiting branches (Figs. 37, 42, 43, 50, and 54), one (Fig. 51) a thorny branch.

The cone-bearing plants (Figs. 59-67) have only simple leaves. Each piece, no matter how small and scale-like, may have a branch growing from its axil, and so may form a whole leaf. A study of these figures, together with the observation of trees, will soon teach the student what constitutes a leaf.

Arrangement.—There are several different ways in which leaves are arranged on trees; the most common plan is the alternate; in this only one leaf occurs at a joint or node on the stem. The next in frequency is the opposite, where two leaves opposite each other are found at the node. A very rare arrangement among trees, though common in other plants, is the whorled, where more than two leaves, regularly arranged around the stem, are found at the node. When a number of leaves are bundled together,—a plan not rare among evergreens,—they are said to be fasciculated or in fascicles. The term scattered is used where alternate leaves are crowded on the stem. This plan is also common among evergreens.

Caution.—In some plants the leaves on the side shoots or spurs of a twig are so close together, the internodes being so short, that at first sight they seem opposite. In such cases, the leaf-scars of the preceding years, or the arrangement of the branches, is a better test of the true arrangement of the leaves. The twig of Birch shown in Fig. 5 has alternate leaves.

There is one variety of alternation, called two-ranked, which is quite characteristic of certain trees; that is, the leaves are so flattened out as to be in one plane on the opposite sides of the twig (Fig. 6). The Elm-trees form good examples of two-ranked alternate leaves, while the Apple leaves are alternate without being two-ranked. Most leaves spread from the stem, but some are appressed, as in the Arbor-vitæ (Fig. 7). In this species the branches are two-ranked.

Parts of Leaves.—A complete leaf consists of three parts: the blade, the thin expanded portion; the petiole, the leafstalk; and the stipules, a pair of small blades at the base of the petiole. The petiole is often very short and sometimes wanting. The stipules are often absent, and, even when present, they frequently fall off as soon as the leaves expand; sometimes they are conspicuous. Most Willows show the stipules on the young luxuriant growths.

Veining.—The leaves of most trees have a distinct framework, the central line of which is called a midrib; sometimes the leaf has several other lines about as thick as the midrib, which are called ribs; the lines next in size, including all that are especially distinct, are called veins, the most minute ones being called veinlets (Fig. 8).

Kinds.—Leaves are simple when they have but one blade; compound when they have more than one. Compound leaves are palmate when all the blades come from one point, as in the Horse-chestnut; pinnate when they are arranged along the sides, as in the Hickory. Pinnate leaves are of two kinds: odd-pinnate, when there is an odd leaflet at the end, as in the Ash, and abruptly pinnate when there is no end leaflet.

Many trees have the leaves twice pinnate; they are either twice odd-pinnate or twice abruptly pinnate. The separate blades of a compound leaf are called leaflets. Leaves or leaflets are sessile when they have no stems, and petiolate when they have stems.

When there are several ribs starting together from the base of a blade, it is said to be radiate-veined or palmate-veined. When the great veins all branch from the midrib, the leaf is feather-veined or pinnate-veined. If these veins are straight, distinct, and regularly placed, the leaf is said to be straight-veined. The Chestnut is a good example. Leaves having veinlets joining each other like a net are said to be netted-veined. All the trees with broad leaves in the northern United States, with one exception, have netted-veined foliage. A leaf having its veinlets parallel to one another is said to be parallel-veined or -nerved. The Ginkgo-tree, the Indian Corn, and the Calla Lily have parallel-veined leaves. The narrow leaves of the cone-bearing trees are also parallel-veined.

Forms.—Leaves can readily be divided into the three following groups with regard to their general outline:

1. Broadest at the middle. Orbicular, about as broad as long and rounded. Oval, about twice as long as wide, and regularly curved. Elliptical, more than twice as long as wide, and evenly curved. Oblong, two or three times as long as wide, with the sides parallel. Linear, elongated oblong, more than three times as long as wide. Acerose, needle-shaped, like the leaf of the Pine-tree.

2. Broadest near the base. Deltoid, broad and triangular. Ovate, evenly curved, with a broad, rounded base. Heart-shaped or cordate, similar to ovate, but with a notch at the base. Lanceolate, shaped like the head of a lance. Awl-shaped, shaped like the shoemaker's curved awl. Scale-shaped, short, rounded, and appressed to the stem. The Arbor-vitæ has both awl-shaped and scale-shaped leaves.

3. Broadest near the apex. Obovate, same as ovate, but with the stem at the narrow end. Obcordate, a reversed heart-shape. Oblanceolate, a reversed lanceolate. Wedge-shaped or cuneate, having a somewhat square end and straight sides like a wedge.

These words are often united to form compound ones when the form of the leaf is somewhat intermediate. The term which most nearly suits the general form is placed at the end; thus lance-ovate indicates a leaf between lanceolate and ovate, but nearer ovate than lanceolate; while ovate-lanceolate indicates one nearer lanceolate.

Bases.—Oftentimes leaves are of some general form, but have a peculiar base, one that would not be expected from the statement of shape. An ovate leaf which should have a rounded base might have a tapering one; it would then be described as ovate with a tapering base. A lanceolate leaf should naturally have a tapering base, but might have an abrupt one. Many leaves, no matter what their general form may be, have more or less notched bases; such bases are called cordate, deeply or slightly, as the case may be; and if the lobes at base are elongated, auriculate. If the basal lobes project outward, the term halberd-shaped is used. Any form of leaf may have a base more or less oblique.

Points.—The points as well as the bases of leaves are often peculiar, and need to be described by appropriate terms. Truncate indicates an end that is square; retuse, one with a slight notch; emarginate, one with a decided notch; obcordate, with a still deeper notch; obtuse, angular but abrupt; acute, somewhat sharpened; acuminate, decidedly sharp-pointed; bristle-pointed and awned, with a bristle-like tip; spiny-pointed, with the point sharp and stiff (Holly); mucronate, with a short, abrupt point.

Margins.—Entire, edge without notches; repand, slightly wavy; sinuate, decidedly wavy; dentate, with tooth-like notches; serrate, with notches like those of a saw; crenate, with the teeth rounded; twice serrate, when there are coarse serrations finely serrated, as on most Birch leaves; serrulate, with minute serrations; crenulate, with minute crenations. Leaves can be twice crenate or sinuate-crenate. Revolute indicates that the edges are rolled over.

When a leaf has a few great teeth, the projecting parts are called lobes, and the general form of the leaf is what it would be with the notches filled in. In the description of such leaves, certain terms are needed in describing the plan of the notches, and their depth and form.

Leaves with palmate veining are palmately lobed or notched; those with pinnate veining are pinnately lobed or notched. While the term lobe is applied to all great teeth of a leaf, whether rounded or pointed, long or short, still there are four terms sometimes used having special signification with reference to the depth of the notches. Lobed indicates that the notches extend about one fourth the distance to the base or midrib; cleft, that they extend one half the way; parted, about three fourths of the way; and divided, that the notches are nearly deep enough to make a compound leaf of separate leaflets.

So leaves may be palmately lobed, cleft, parted or divided, and pinnately lobed, cleft, parted or divided. The term pinnatifid is often applied to pinnately cleft leaves. The terms entire, serrate, crenate, acute-pointed, etc., are applied to the lobes as well as to the general margins of leaves.

Surface.—The following terms are needed in describing the surface of leaves and fruit.

Glabrous, smooth; glaucous, covered with a whitish bloom which can be rubbed off (Plum); rugous, wrinkled; canescent, so covered with minute hairs as to appear silvery; pubescent, covered with fine, soft, plainly seen hairs; tomentose, densely covered with matted hairs; hairy, having longer hairs; scabrous, covered with stiff, scratching points; spiny, having stiff, sharp spines; glandular-hairy, having the hairs ending in glands (usually needing a magnifying glass to be seen).

Texture.—Succulent, fleshy; scarious, dry and chaffy; punctate, having translucent glands, so that the leaf appears, when held toward the light, as though full of holes; membranous, thin, soft, and rather translucent; thick, thin, etc.

Duration.—Evergreen, hanging on the tree from year to year. By noticing the color of the different leaves and their position on the twigs, all evergreen foliage can readily be determined at any time during the year. Deciduous, falling off at the end of the season. Fugacious, falling early, as the stipules of many leaves.

Chapter IV.
Flowers and Fruit.

The author hopes that those who use this work in studying trees will become so much interested in the subject of Botany as to desire more information concerning the growth and reproduction of plants than can here be given. In Professor Asa Gray's numerous works the additional information desired may be obtained: "How Plants Grow" contains an outline for the use of beginners; "The Elements of Botany" is a more advanced work; while the "Botanical Text Book", in several volumes, will enable the student to pursue the subject as far as he may wish. In this small book the barest outline of the parts of flowers and fruit and of their uses can be given.

Flowers.—Parts. The flowers of the Cherry or Apple will show the four kinds of organs that belong to a complete flower. Fig. 9 represents an Apple-blossom. The calyx is the outer row of leaves, more or less united into one piece. The corolla is the row of leaves within the calyx; it is usually the brightest and most conspicuous part of the flower. The stamens are the next organs; they are usually, as in this case, small two-lobed bodies on slender, thread-like stalks. The enlarged parts contain a dust-like material called pollen. The last of the four kinds of parts is found in the center of the flower, and is called the pistil. It is this part which forms the fruit and incloses the seed.

The stamens and the pistil are the essential organs of a flower, because they, and they only, are needed in the formation of seeds. The pollen from the stamen, acting on the pistil, causes the ovules which are in the pistil to grow into seeds.

The calyx and corolla are called enveloping organs, since they surround and protect the essential parts.

The pieces of which the calyx is composed are called sepals. The Apple-blossom has five sepals.

The pieces that compose the corolla are called petals.