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Yet there is no waste which could have been avoided. The quantity of pollen produced in some cases is enormous, infinitely greater than is needful for the fertilization of the pistil; but this is a wise arrangement to secure the desired result, in spite of the influence of winds, and the unfavourable position which the pistil often occupies. In most instances, it is true, the stamens are so arranged as to overtop the pistil, being longer in plants whose flowers are upright, and shorter in drooping flowers. But when we consider that many plants have the stamens and pistils on different flowers, and, still further, that, in the case of cer tain large trees, one tree bears stamens only, and another pistils only, the wonder is, not that so much pollen should have been provided, but that the fertilization should be effected with so much certainty. The pollen is often carried to its destination by the wind, the very influence which seems at first sight likely to cause its entire waste; and, in some cases, the sugary secretions of the corolla attract bees and other insects, to whose bodies the little grains of pollen adhere, and are thus deposited in the place for which nature intended them. Where shall we find a more interesting example of the way in which “ all things work together” to promote the designs of Providence ?
PRESERVATION AND DISPERSION OF SEEDS. The one great intention of nature in the structure of flowers scems to be the perfecting of the sced, and (what is part of the same intention the preserving of it till it be perfected. This is seen, in the first place, in the care which is taken that all the organs immediately concerned in reproduction have every advantage of situation that can be given them. Thus the stigma, ovary, and anthers are lodged in the central recesses of the plant, and exposed only when exposure is beneficial to them. While still tender and immature, they are shut up and sheltered in the bud; as they acquire greater firmness of texture, the expansion of the petals discloses ties to the 12: 24 aér; he is the late, is rary anks, by the Text is otse F AT fore, the light aci beat resered a tea tratze 690care surface of the ox Mazy Fen Lare a so the sitzta faculty of dzicz, ot going to use, ten ist seis in, and opening azzin in the bortizz. Cicers open ocis by night, and at cid-day are u ses cosed. There is, indeed, scarcely aby Lor of the day, at which these pbenomena are not girz on with more or less intersity. We can easily see the object of this wonderful sensibuity. It is simply that the çetais rray so dispose themselves as to shelter the tender istoria organs, opening or closing as this purpose Tenders either change of position requisite.
Sach are a few of the precautions taken to secure the safe development of the organs on which the production of the feed depends. If we now look at the seed itself, we shall find that no less care is bestowed on its preservation. As the filower decays, the whole energies of the plant are devoted to the pursing of the little embryo which it has left behind. Gradually the embryo and its enclosing ovary increase in bulk, assuming, in different plants, an incalculable variety of forms, all of which evidently conduce to the security of the sced. The results of this process are seen in the endless diversity of fruits. Sometimes, as in cherries and other stone fruits, the seed is enclosed in a strong shell, which is itself surrounded by a pulp; sometimes, again, as in grapes, oranges, and berries, it is plunged over-head in a glutinous syrup, contained in a skin or bladder; at other times, as in apples and pears, it is embedded in the heart of a firm fleshy covering ; or, as in strawberries, pricked into the surface of a soft pulp. These and many other varieties occur in what are popularly called fruits. But, if we take into account the matured seed-vessels of grassos, herbs, trees, and all other seed-bearing plants, which are also fruits in the strict botanical sense, the number of different forms to be met with is altogether incomputable. Plants of the pea tribe have their seeds regularly disposod in pods, which exclude the wet even in the heaviest rains; and these pods are sometimes lined with a soft down, as in the bean, or distended, as in senna, like a blown bladder. A woolly substance envelops the seeds of the cotton plant, while those of the thistle and artichoke are barricaded with spikes and prickles. In the grasses we find the seeds enclosed in hard shells or tunicles, with which they are so intimately connected as to be inseparable.
As soon as the seeds, whose safety is so carefully provided for, have been matured, the next business is to disperse them. They cannot serve the purposes for which they are designed while they remain wrapt up in their several coverings. Accordingly, some fruits, whenever the seeds within them are fully ripe, burst open in various ways so as to scatter them; while others fall to the ground without opening, and their seeds are liberated by the decay of the surrounding substance. Various agencies then contribute to their dispersion. Streams often convey to a distance the secds of plants that grow on their banks. Winds are available for the same purpose, and hence many seeds, such as those of the thistle and dandelion, are endowed with appendages not improperly called wings. By means of these they are enabled to float in the air, and it is no uncommon thing, in a windy day, to see them far away from the parent plant. Some pulpy fruits are picked up by birds, and the little seeds they contain, being hard and indigestible, are soon deposited again in a state quite fit for germination. And, last of all, the seeds of plants valuable as food have been dispersed by man over such parts of the globe as are suited for their cultivation.
Thus we have arrived at the point from which we started in our sketch of the growth and functions of plants. From the seed are developed root, and stem, and leaves, by which the plant is nourished and increased. Then comes the flower, filling the air with perfume, and clothing the earth with beauty. But these are not the main objects of its existence. It exhausts itself in perfecting the seed; and this seed, again committed to the earth, gives birth, in its turn, to new plants and flowers, similar to that from which
it sprung. And so on, from generation to generation, and from age to age, the wheel of vegetable life incessantly revolves—a small, but beautiful and essential part of the stupendous machinery of nature.
QUESTIONS FOR EXAMINATION.
Why is reproduction necessary in the vegetable kingdom? Which part of the plant contains the organs of reproduction? What are cryptogamic plants ? phanerogamic plants? What classes formerly spoken of are included in this last? What is the outer covering of the flower called? What are the dit. ferent parts of this covering called? What part of the flower is in general beautifully coloured? Of what use is it? What are petals? stamens? whorls ? What relation subsists between the number of petals and that of stamens? How are the parts of successive whorls arranged? What part of the flower occupies the centre? Which is the essential part of the stamen? With what is it filled? What is the use of pollen? Describe the different parts of the pistil. How is the pollen conveyed to the stigma? How does it obtain communication with the ovule? What is the effect of this communication on the ovule ? on the rest of the flower ? Why do some plants produce so much pollen? How do bees convey the pollen to its destination? Show how the seed-producing organs of plants are protected and cared for. What is meant by plants "going to sleep?" Why do they so? How are the seeds of different plants protected till they reach maturity? Give examples. How are they then dispersed ? Give examples.,
GOD IN NATURE.
THERE lives and works
CHARACTERISTICS OF SCOTLAND. (Part of the Address of SIR DAVID BREWSTER at the Opening of Edinburgh University, 4th November, 1863.] THERE are fèw countries that possess objects and institutions of a more varied interest' than our own. Distant enough from the frigid zòne, indénted by sinuous èstuaries, and spacious bays and deep inlets of the ocean, Scotland! enjoys a clímatel mild and salubrious, equally removed from the rigours ofan arctic winter' and the scorching héats of a tropical sùn. No exhalations poison íts átmosphere, no sirocco blìghts it, and we know no more of the tornado and the earthquakel than what makes us gràteful for our ignorance. At all seasons! Scotland is accessible to the strànger —whether he comes as a pilgrim with his staff and his scríp, or is welcomed to its shores! by the light-beacons that guard them by night. Ráilroads' carry him along its sèaboard, over its mountain cháins, and through its picturesque valleys; and the busy stéamerl plies unceasingly along its winding and rugged coasts. With this extérnal characterl the intérior of our peninsula corresponds. Mountain ranges of lofty aspects—hérel rising into peaks of granite, thèrel descending into precipices of gneiss, or running into pillars of basált-embosom lákes of the purest and most limpid water, or give birth, in their córries, to the elements of the cataract, whích, at a lower level, rushes over its prècipices, and to the sources of the mighty ríver' which adorns and fértilises the region of industry and life. In descending to the level of vegetable fórms, we enter upon scéneryl at once picturesque and beautiful-hère! clothed with sober héath, thére' gay with the richest vèrdure—at òne place, the crevice of the róck pushing out its crumped and wild vegetation, and at another, the river bànkl displaying its embroidery of birch and dak, while the flanks of the eternal hills' retire into purple shàdow, invested with the folds of the gloomy and the stately pine. Amidst scenes like thése, the geologist