ePub 版
[ocr errors]

of the leaves which had withered in autumn, delight us with new verdure and beauty.

The poet Cowper has the following lines on the formation of buds; they evince that character of piety which distinguishes this excellent man, in all his writings:

Fig. 28.

"When all this uniform uncoloured scene,
Shall be dismantled of its fleecy load,
And flush into variety again,

From dearth to plenty, and from death to life,
Is Nature's progress, when she lectures man
In heavenly truth; evincing, as she makes
The grand transition, that there lives and works
A soul in all things, and that soul is GOD.
HE sets the bright procession on its way,
And marshals all the order of the year;

HE marks the bounds which winter may not pass,
And blunts his pointed fury; in its case,
Russet and rude, folds up the tender germ,
Uninjured, with inimitable art;

And ere one flowery season fades and dies,
Designs the blooming wonders of the next."

You may here see a representation of two scaly buds; one of which appears as if cut vertically, in order to show the germ or embryo which is enfolded by the scales.

Some French botanists* have explained the formation of the scaly covering of buds in a manner somewhat different from the generally received opinion. They suppose that the bud does indeed begin its existence in the latter part of summer, the eye being then formed; that it exists in this state during the winter, but being acted upon by some change of the temperature, it begins to force its way through the bark into the atmosphere; here the young leaves which would put forth, becoming chilled by an ungenial atmosphere, contract and harden, and at length form scales. These scales afterwards protect the new leaves, that, urged by the same vegetable instinct, are in their turn, seeking to emerge into fight and air. If we admit this explanation with respect to the formation of scales, it seems not difficult to account for that of the downy substance, which, lining these scales, protects the embryo leaves and flowers from cold; and the covering of varnish, which defends them from moisture. When the leaf becomes a scale, it then absorbs from the sap but a portion of what was destined for its use, and it is supposed that this sap is converted into the resinous substance, or varnish. With re


* De Candolle, and some others.

Opinion of some botanists with respect to the formation of the scaly covering of buds.

spect to the downy coat upon the inside of the scales, this may be seen in the rudiments of the leaves, if examined before the bud is developed.

These hypotheses do not, in any degree, derogate from the wisdom of Him, of whom Cowper says, that " with art inimitable, he folds up the tender germ;" for whether He acts by secondary causes, or "Speaks and it is done,” the design is alike apparent.

The term bud, in common language, extends to the rudiments of all plants, whether with scales or without, which originate upon other living plants. Buds with scales are chiefly confined to the trees of cold countries. In the northern part of the United States, there are few trees which can endure the cold weather, without this security. In Sweden, it is said, there is but one shrub* destitute of buds, and this from the peculiarity of its situation, is always protected from the inclemencies of the weather.

It appears that no perennial plants, but those furnished with scaly buds, can live in climates where it snows a part of the year; the trees of the torrid zone, the wood of which appears hard and firm, perish in our climate. In warm climates the buds of the trees are without scales, as the tender shoots do not need their protection.

That there is, in reality, a difference in the nature of vegetables, as well as animals, is very apparent; an orange tree will never form scales to protect its buds from cold, any more than the most delicate tropical animals can resist the rigors of a polar climate. There are cases however in which plants, as well as animals, change their habits. The horse-chesnut, in India, its native climate, unfolds its leaves to the atmosphere, without their receiving any check in their developement; in a colder climate, the leaves in attempting to unfold, are checked in their progress, and degenerate into scales, and form buds.

Monocotyledonous plants seldom produce more than one bud annually. On the summit of the palm appears the bud, containing the leaves and flowers; from the centre of this bud, a footstalk springs up bearing the flower, while the leaves spread out at its base. The following year the old leaves decay, forming by their indurated remains a ring around the stipe of the palm, and a new bud is formed upon its summit as before. * A species of Rhamnus, which grows under trees, in marshy forests.

These hypotheses, if admitted, do not derogate from the wisdom of the Creator-The term bud, how extensive in its application-Scaly buds chiefly confined to cold countries-Difference in the nature of vegetables-Plants sometimes change their habits; example, the horse-chesnut--Buds of the palm.

This bud of the palm, from its form and size, is often called the cabbage.

Some botanists enumerate four kinds of buds: 1st. the bulb; 2d. the bulbille; 3d. the turion, or little bulb; and 4th. the bud.


We have already considered the bulb, under the head of roots. Botanists have occasioned some confusion in the science by placing the bulb among roots and buds; yet they seem to bear a close analogy to both. An onion bulb, like the bud of the palm, contains the stem, leaves and flower; its radicles are indeed the true root.

The bulbille is often found in the axils of leaves, as was represented at Fig. 26.


Fig. 29.


The turion differs but little, except in size, from the bulb; it appears upon roots of perennial plants, as may be seen in Fig. 29, a.

Of the proper bud, there are three sorts;

1st. The flower bud, which is of a short round form, and contains the rudiments of one or several flowers, without leaves, folded over each and surrounded with scales. It is often found at the extremities of small short branches; this is the kind of bud which is employed in grafting or innoculating. This operation is performed by cutting into the bark of another tree, and placing a bud or several buds in the aperture.

2nd. The leaf bud, contains the rudiments of several leaves without flowers; it is usually longer and more pointed than the flower bud.

3rd. The mixed bud; containing both leaves and flowers. In the peach we have examples of the two first divisions; the leaf and flower bud being distinct. In the lilac they are enclosed together in the same bud.

The leaf buds, if taken from the tree and planted in the earth, will grow and put forth roots; but the flower buds in the same situation will perish. You will perceive that a striking analogy exists between buds and seeds, as well as between buds and roots.

You have now seen the manner in which buds commence their existence; and how they gradually unfold themselves until they become in their turn branches, covered with leaves and flowers. In considering this subject you cannot but have

Different kinds of Buds-1st. Bulb-2d. Bulbille-Turion-Proper budFlower bud-Leaf bud-Mixed bud--Reflections suggested by a view of the subject.


been impressed with a sense of the goodness of that great Being who watches with unceasing care, over his vast creation. observe the progress of life, whether in the vegetable or animal kingdoms, is highly interesting to an investigating mind; but here the power of man can achieve nothing; he may plant and water, but God alone giveth the increase.

A bud lives, an infant lives; both are destined to grow, and to pass through physical changes; but the bud, although active with a principle of life, knows not its own existence; while the infant becomes conscious of its own powers and faculties, capable of loving those who have contributed to its well being, and especially of adoring the great Author of its existence.

man race.

It is delightful, while gratifying our natural love of knowledge, by inquiring into the economy of nature, to be thus met at every step, with new proofs of the goodness and wisdom of the Author of Nature, particularly as manifested towards the huTo discover the character of the Deity, should indeed be the end and aim of all knowledge; and even should an occasional digression from the subject of your present study, retard your progress in botanical investigations, the loss would be slight, compared to the gain of one pious and devout aspiration of the heart.

When we become so deeply engaged in philosophical speculations, as to forget Him whose works we study, we have wandered far from the path of true knowledge. It was not thus that Newton studied the laws of matter, or Locke and Watts the laws of mind, or Paley the animal and vegetable physiol ogy; these great and good men, made their rich treasures of knowledge subservient to one great design, that of illustrating the character of God, and teaching our duty to him.

Of Leaves.

You all know what is meant by the leaf of a vegetable; but were you called on to give a definition of the term leaf, you might find it more difficult than at first you would imagine. Young persons are often disconcerted, when asked by their teachers to explain some word of which they have an idea, and yet find themselves unable to give a definition; but although

Comparison between a bud and an infant-The goodness of God particularly manifested towards the human race-Philosophical speculations should not lead us to forget the Author of nature-Difficulty in giving correct definitions..

the pupil may be surprised at this fact, it is not unaccountable to those who know, that although we may have the picture of an object in the mind, it is not always easy to convey our conceptions to the minds of others. To give correct definitions of terms, is one of the greatest difficulties in science.

The manner in which different persons describe objects, varies with the degree of knowledge possessed respecting their properties. For example; in attempting to describe common salt, if a person knew nothing more of it than his unassisted senses had informed him, he would speak of its colour, taste, and other obvious properties; one familiar with the principles of chemistry, would first speak of the materials which compose salt; he would describe it as a compound substance, consisting of chlorine and sodium; and then might enumerate its properties. In the first definition, given without any reference to scientific principles, there is nothing so definite as to afford a certain mark of distinction between salt and other substances; in the chemical definition, we have a test for salt, in a knowledge of its composition, which distinguishes it from all other substancés.

In botanical definitions, we do not include the constituent elements of the vegetable substance; this belongs to the department of chemistry, but we consider the external forms and uses of the various parts of the plant.

One botanist* says, "leaves are organs of an expanded form, almost always of a green colour, internally vascular, and more or less pulpy." Another botanistt says, "the leaf may be defined to be a temporary organ of plants, which performs nearly the same function in the economy of vegetable life, as the lungs perform in the animal; or, they are the respiratory organs of plants."

We might go on quoting from different authors, each of whom describe according to their own manner of considering the subject; but as our object is, to express botanical facts in the most simple terms, we will merely add to the definitions above given, one which, with your present knowledge, is as scientific as you can understand.

The leaf is generally a thin, flat organ, consisting of an expansion of the fibres of the bark, connected by a substance which is called the cellular tissue; the whole is covered with a green coat or skin called the cuticle. Leaves are furnished,

[blocks in formation]

Descriptions of objects vary with our knowledge of their properties-Differ ent definitions of leaves-General description of a leaf.

« 上一頁繼續 »