The Vegetable World: Being a History of Plants, with Their Botanical Descriptions and Peculiar Properties

Fig. 283.—Haricot Bean germinating. influence of an energetic agent, which is developed near the germs at the time of the seed ge? agent has received the name of diastase. —; this dissolvingminating The starchy matter transformed by diastase into a soluble substance, bears the name of destrin. Destrin is modified in its tum under the influence of diastase, and becomes sugar. We shall be right, then, in saying, that the first nourishment of the yours plant is sugared water. Efforts have been made to discover if a grain of starch, while being transformed into destrin, shows any visible trace of so com”

plete a molecular change; whether it disappeared suddenly under the action of diastase, or is only gradually changed into a somewhat similar substance, so that one could follow out with the microscope all the phases of this change. It has been proved that this change is only, brought about by successive steps, and we are enabled to follow _ the progress of this alteration in the germination of several plants. To return to the evolution of the embryo. However thus nourished and strengthened, either at the expense of the albumen, or of its own cotyledons, the embryo quickly presses the integuments covering it on

Fig. 284.—Germination of the Spanish Bean.all sides, which, in the end, are broken, thus giving 1it a passage through. This rupture takes place sometimes in an irregular manner, as in the Spanish

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Fig. 285.—Germinating of the Sugar Cane. and other Beans (Fig. sometimes in a very regular 284); manner, as in the Virginian Spider-wort, the Date, and the

Flowering Cane. In the last case the embryo appears outside, through an opening very regularly cut out in the integument covering the seed. This opening is hidden at first by a sort of disc, or lid, which the little root of the embryo lifts up in order to make its way out and bury itself in the ground.

Fig. 285 shows the successive stages through which a germinating seed of the Sugar Cane passes. The little lid is lifted up and cast aside (1); the cotyledon is developed, elongated horizontally, and the radicle pushes out (2); the radicle is sometimes pointed to the ground (3); the gemmule, or bud, sallies out from the opening of the cotyledon, which is transformed into a sheath (4); the radicle is increased in size, and the rudiment of the stalklet appears (5); the stalklet is formed (6). The seeds of most of the monocotyledonous plants are provided with albumen, and at the time of germination the cotyledonous limb remains shut up in the seed, as we see in the Palms, Flowering Cane, and Virginian Spider-wort.

Fig. 286.—Germination of a seed without albumen, showing the Cotyledons which rise on the stem.

[illegible artist signature]

PART 11.

CLASSIFICATION OF PLANTS.

Every plant which grows on the surface of the earth or in the waters constitutes a distinct individuality. The careful examination and comparison of a certain number of these individuals of the Vegetable World will lead to the admission that many are quite identical in some of their characteristics, while others possess no character in common. Examine the individual plants, for instance, which compose a field of oats; in each the root, the stem, the flowers, the fruit, present the same identical characters. The seed of any one whatever of these plants will yield other plants like those of the field. Every individual in the field belongs _ to the same species—to the species Avena

The species, then, is a collection of all the individuals which resemble each other, ie which will reproduce other individuals like themselves. These species may present, as the result of diverse influences, such as change of climate or cultivation, differences more or less marked—tendencies more or less tenacious in resisting efforts to withdraw them from the original type. To these, according to theit importance, botanists give the name of varieties and sub-varieties. ‘The Wheat-plant, the Vine, the Pear, the Apple, and most of our cultivated legumes, all yield, under the influence of culture extending over along series of years, plants altogether different from the original in their exterior; but they preserve, one and all, the essential characters of the species. They are varieties of the Wheat-plant, of the Vine, of the Pear, of the Apple.

The assemblage of a certain number of distinct species present- 3 o

WA ing the same general characteristics, the same disposition of organs, the same structure of flower and fruit, constitute a group to which the name of genus is applied. Rosa Canina, R. Villosa, and F. Sabini are three different species of the same group—the — genus Hosa. The words oak, poplar, barley, are collective com-— _ mon names, which served, long before Natural Science existed, to designate a certain group of plants. These are true generic names of popular creation, which botanists have accepted because they were the result of exact observation. “A man of observant — eye and quick intelligence,” says Pyramus de Candolle, “ would observe certain groups in the vegetable kingdom which we call genera, before discerning the species.”.

The germs of Botanical Science are to be sought for in the rudimentary state in very remote antiquity. In the sacred writ-_ ings we meet with constant allusions to the vegetable world. The cultivators of the science among the early Greeks and Romans — were not Botanists, but Rhizotome, or root-cutters, since they — directed their attention to the roots in search of medicinal properties. Aristotle of Stagira, who lived four hundred years before { our era, may be regarded as the founder of botany; Mithridates, 2 several Greek kings, and the younger Juba, King of Mauritania, were among its cultivators. They established Botanic Gardens, " - some probably from love of the science, others of them in order: to cultivate the deadly plants from which poisonous juices were | obtained. Nicander of Colophon, Cato, Varro Columella, Virgil, a Pedacius, Diascorides of Silicia, and lastly, the elder Pliny, all — = dwell upon the wonders of vegetation; and war, notwithstanding. its desolating tendencies, was made to promote the interests of — science. To the Arabians of the twelfth century we are next indebted for our knowledge of botany. After them the darkness of the Middle — Ages set in, and it is only since the illustrious Venetian, Marco Polo, came to examine and describe the wonders of the East, that the darkness has been dispelled. He examined the treasures of Asia and the East Coast of Africa, described many plants of India and the Indian Ocean, and from his day to the present our knowledge the names of plants, as well as of their structure and physiology, , has been continually on the increase.

The science of botany, as now understood, cannot be held, how- ’ ever, to date farther back than two centuries. In the year 1682 ' Nehemiah Grew, the Secretary to the Society of London, after-

| wards the Royal Society, published his “‘ Anatomy of Plants.”* A

' few years later the French botanist Tournefort, then Professor of ' Fig. 287.—Tournefort.

| Botany at the Jardin des Plants, published his “Elements of

• Botany,” being the first attempt to define the exact limits of genera in vegetables. Most of the genera established by Teurne-fort remain, proving the correctness of the formula from which he dedueed their common characters. Tournefort succeeded to a large L, £xtent in unravelling the chaos into which the science of botany 0 2

had been plunged from the days of Theophrastus and Dioscorides. Separating genera and species according to their characteristics, hé described no less than 698 genera, and 6,146 species. He announced, at the same time, a system for the classification of plants, eminently attractive, especially if we connect it with the times in which it appeared. The French botanist directed the attention of observers, probably for the first time, to those parts of plants most likely to excite admiration, namely, the different — forms of the corolla. - In selecting the form of the Corolla as the basis of his classification, Tournefort has, perhaps, contributed more to the progress of botany than any other savant of any age. The task of instruction was rendered a pleasure by thus taking, as a subject of scien- — tific inquiry, the most attractive part of the plant. He soon © made adepts of those who had hitherto only contemplated flowers — as the source of an agreeable sensation.

Tournefort first established two grand divisions of the vegetable; world, Herbaceous Plants and Trees. The flowers of herbaceous plants are furnished, or not, with a corolla; they are simple of compound; the corolla is Monopetalous or Polypetalous; i 38 regular or irregular. Such were some of the considerations 0 which Tournefort founded his classification of herbaceous vege- a tables. As to trees, their flower is provided with a corolla, or it is not; that is to say, it is Apetalous or Petalous. The apetalous trees have the flowers disposed in catkins, or they have not; the petalous: trees have the corolla regular or irregular.

Arranged and tabulated, according to the systemof Tournefort, the vegetable world will stand as follows:—

FLOWER-BEARING TREES.

ly so called. i — a ret Monoreta.ovs...... Monopetalons ) Polypetalous gular.. Rosacem. Petalous, Peseweh. Paprionacex.

Trees, then, form five classes. de

In the. class of Apetalous plants are ranged the Box-tree ant” the Pistachio;in the class of Amentacee are the Oak, theWoler |ttee, and the Willows. |

7 The Lilies, the Elder, and the Catalpa of India belong to the the Apple, the Pear, and the Cherry to division;__ AMonopetalous the Rosacee; the Acacia, the Laburnum, to the Papilionacee.

| he herbaceous flowering plants without corolla are subdivided

into three classes: (1) plants provided with stamens; (2) flowerless _ plants provided with seeds; (3) plants in which the flowers and _ fruits are not apparent. Wheat, Barley, and Rice belong to apetalous herbaceous plants, with stamens; the Ferns and Lichens to flowerless apetalous herbaceous plants, provided with fruits; and the Mosses and Mushrooms to apetalous herbaceous plants without

SESgtotisRatio,5than flowers and having no apparent fruit.

Tournefort formed fourteen classes of flowering herbaceous plants provided with a corolla. The first twelve classes include the herbaceous plants with isolated and distinct flowers; the three others include the flowering herbs, which constitute the compositee, namely, the Floscular, or flowers with funnel-shaped petals; the semi-floscular and the radiating plants, such as the Sunflower and the Daisies. The following is a tabular arrangement of simple-flowering herbaceous plants, according to the grouping of Tournefort:—

In addition, Tournefort has subdivided each class into sections, - More or less considerable, based upon its composition, upon the consistence of its fruit, and upon some particular modifications of the form of the corolla.

Such is the first known system for the classification of plants. This scientific conception met with great favour among his con-poraries on account of its simplicity. Nevertheless, in its application this system presented many difficulties. The form of the corolla is not always so exactly appreciable that the class to which the plant belongs can be settled from that character alone. But the