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flower already examined. It is necessary that I should remark that our stock must be a single one. Those fine purple double stocks that we prize so highly would be totally disregarded by a botanical student, who considers all double flowers either as the sport of Nature or the effect of art, and consequently unsuited for his investigation.
In the examination of this flower the first thing that you will see is the calyx, an exterior part which was wanting in the crown imperial. In the stock it consists of four pieces, which we must call leaves, leaflets, or folioles, having no proper name by which to express them as we have for the pieces that compose the corolla. These leaflets are commonly unequal by pairs. That is, there are two opposite and equal of a smaller size, and two others, also opposite and equal, but larger. This calyx contains a corolla composed of four petals. I say nothing of their colour, because that forms no permanent part of their character. Each of these petals is fastened to the receptacle or bottom of the calyx, by a narrow pale part called the claw of the petal, and this spreads out over the top of the calyx into a large, flat, coloured piece, distinguished by the name of lamina, or the border. Admire the regularity of the corolla of the flowers of this tribe. The petals grow generally wide of each other, and exactly opposite to one another, forming a figure resembling that of a cross, which has given them the name of cruciform, or cross-shaped. The petals of the corolla and the leaflets of the calyx are placed alternately, and this position prevails in all flowers in which is a correspondent number of petals and leaflets. In the centre of the corolla is one pistil or pointal, long and cylindrical, chiefly composed of a germ, ending in a very short style, and that terminated by an oblong stigma, which is bisected, or divided into two parts that are bent back on each side.
It remains now to speak of the stamens. There are six of them. two shorter than tho other four. opposite to each other: these arc separated—as are also the others—in pairs. When the corolla withers, the germ increases considerably in length, and thickens a little as the fruit ripens; when it is ripe it becomes a kind of flat pod called silique. This silique is composed of two valves, each covering a small cell, and these cells are divided by a thin partition. When the seeds are ripe, the valves open from the bottom upwards to give them passage, and remain fast to the stigma at top. Then you may discover the flat round seeds arranged along each side of the partition, and you will find that they are fastened alternately to right and left (by a short pedicle or footstalk) to the sutures or edges of the partition. The great number of species in this class has determined botanists to divide it into two sections, in which the flowers are perfectly alike; but there is a material difference in the fruits, pericarps, or seed vessels.
Although I have wandered far from the subject, I have not forgotten my promise of describing the curious mechanism employed in the structure of the pea flower.
On examining this elegant and wonderful blossom you will observe that the calyx is of one piece, divided at the edge into five segments or distinct points, two of which are wider than the other three, and are situated on the upper side of the calyx, whilst the three narrower ones occupy the lower part. The corolla is composed of four petals. The first is broad and largo, covering the others, and standing, as it were, on the upper part of the corolla, to defend and shelter it, in the manner of a shield, from the injuries of the weather. By way of pre-eminence it is called the standard or banner. In taking off the standard, remark how deeply it is inserted on each side, that it may not easily be driven out of its place by the wind. The side petals, distinguished by the name of wings, are exposed to view by taking off the banner. They are as useful in protecting the sides of the flower as the banner is in covering the whole. Take off the wings and you will perceive the keel, called so on account of its fancied resemblance to the shape of the bottom of a boat; this encloses and preserves the centre of the flower from harm, -which its delicate texture might receive from air and water.
If you are curious to examine the contents of this little casket, slip the keel gently down, and you will discover a membrane, terminated by ten distinct threads which surround the germ or embryo of the legume or pod. Each of these threads or filaments is tipped with a yellow anther, the farina of which covers the stigma which terminates the style or goes along the side of it. The filaments form an additional defence to the germ from external injuries. As the other parts decay and fall off, the germ gradually becomes a legume or pod. This legume is distinguished from the silique of the cruciform tribe by the seeds being fastened to one side only of the case or shell, though alternately to each valve of it. Compare the pod of a pea and a stock together, and you will immediately perceive the difference. The footstalk which supports this flower is slender, and easily moved by the wind. In wet and stormy weather tho pea turns its back to the storm, whilst the banner enfolds the wings by closing about them, and partly covers them: they perform the same office to the keel, containing the essential parts of the fructification. Thus is this flower curiously sheltered and defended from its natural enemies, rain and wind; and, when the storm is over and fair weather returns, the flower changes its position, as if sensible of the alteration, expands its wings, and erects its standard as before.
A FEW BOTANICAL NOTES FOE BEGINNERS.
All the known vegetable productions upon the surface of the' globe have been reduced by naturalists to classes, orders, genera, species, and varieties. The classes are composed of
orders, the orders are composed of genera, the genera of species, and the species of varieties. Let us endeavour to obtain a clearer idea of classes, orders, &c, by comparing them 'with the general divisions of the inhabitants of the earth :—Vegetables resemble man; classes, nations of men; orders, tribes or divisions of nations; genera, the families that compose the tribes; species, individuals of which families consist; varieties, individuals under different appearances.
Linnaeus, dissatisfied with every system invented before his time, undertook to form a new one upon a plan approaching nearer to perfection, and depending on parts less liable to variation. The stamens and pointals are the basis of his classification. He divided all vegetables into twenty-four classes. These classes are subdivided into nearly one hundred orders; these orders include about two thousand families or genera; and these families about twenty thousand species, besides the innumerable varieties produced by the accidental changes of cultivation, soil, and climate. As you acquire accurate notions of stamens and pistils, you will find but little difficulty in mastering the classes and orders, the former depending principally upon the number, the length, the connection, or the situation of the stamens; the latter being founded (in the thirteen first classes) on the number of the pointals, and the others on circumstances to be hereafter explained.
The characters of the genera are marked from some particulars in the flower, unnoticed in the definitions of the classes or orders. The generic description includes all the most obvious appearances in the flower. In a science depending so much on memory and minute definitions, it is advisable to proceed step by step, and make yourself perfectly acquainted with the classes before you advance to the orders. Should you gather a flower in order to know to what class it belongs, observe first whether it be a perfect flower containing both stamens and pointals; if that be the case, examine whether the stamens are entirely separate from the pointal, and from each other from top to bottom. If you find that they are perfectly distinct, and of equal height when at maturity, and are less than twenty in number, the number of them alone will be sufficient to determine the class :—
Those that have one stamen will belong to the first class— Monandria.
Those that have two, to the second—Diandria.
Those that have three, to the third—Triandria.
Those that have four, to the fourth—Tetrandria.
Those that have five, to the fifth—Pentandria.
Those that have six, to the sixth—Hexandria.
Those that have seven, to the seventh—Heptandria.
Those that have eight, to the eighth—Octandria.
Those that have nine, to the ninth—Enneandria.
Those that have ten, to the tenth—Decandria.
Thus far it is easy to arrange each flower under its proper class, as you have nothing more to do but observe the four above-mentioned peculiarities, and to count the stamens, and refer them to their respective classes according to their number. The distinctions in the remaining classes I shall point out in their proper order. The names of the classes are Greek, and express the peculiarities of each; it is absolutely necessary to learn them perfectly by heart, which cannot be considered as a difficult task, as there are but twenty-four of them, and far the greater number terminate in the same word, andria.
Flowers growing wild, without culture, are the most suitable for examination, because those that are domesticated in the rich soil of our gardens are frequently transformed, by change of nourishment, &c, into something very different from what Nature made them. It will be proper to extend your observation to several flowers of the same class, as it sometimes happens that the number of the stamens varies from accidental causes, and if the flowers are disposed in spikes or bunches, the terminating one should be preferred.