This section is from the book "A Library Of Wonders And Curiosities Found In Nature And Art, Science And Literature", by I. Platt. Also available from Amazon: A library of wonders and curiosities.
When seeds are come to maturity, their dissemination is absolutely necessary, since without it no future crop would follow. The great Author of nature has wisely provided for this in various ways. The stems of many plants are long and slender, and being raised above the ground, the wind shakes them to and fro, and by this means are the ripe seeds conveyed to a distance. The seed-vessels of most plants are shut till the seeds are ripe, that so the winds may not scatter them prematurely; and when the proper season arrives, many of these open with such a degree of elasticity as to throw the seeds to a considerable distance. Other seeds have a kind of wings given them, by which they are conveyed to a distance of some miles from the parent plant. These wings consist either of a down, as in most of the composite-flowered plants, or of a membrane, as in the birch, alder, ash, elm, etc. Hence woods, which happen to be destroyed by fire, or any other accident, are soon restored again by new plants.
Some seeds are rough, or provided with a sort of hooks, by means of which they are apt to stick to animals that pass by them, and by this means are carried to the mouths of their burrows, where they meet with proper soil and manure for their growth. Berries and other pericarpies are by nature allotted for aliment to animals; but it is on condition that they shall sow the seed while they eat it: this they do by dispersing the seeds as they are eating; and also after eating, by voiding many of them unhurt, and even in a better state for vegetation than they were before. Thus many kinds of nuts are sown; and thus did the doves of the Moluccas replant with nutmegs those islands of the East, which the sordid avarice of the Dutch had destroyed: Providence thereby frustrating, by feeble but certain means, the contemptible selfishness of that commercial people.
In this manner the woods of northern countries are sown with junipers, by the thrushes and other birds which feed upon these heavy berries. The cross-bill lives upon fir-cones, and the hawfinch upon pine-cones; by means of which the fir and the pine, of various species, are continually planted in vast abundance. In our own country, the common rook has been observed, not only to feed on acorns, but to make holes in the ground with the bill, and hide many: probably they mean only to lay in a stock for future necessity by this process; out certain it is, that thousands of oaks are annually planted by this means. Swine, also, in searching for food,'turn up the earth; and moles, by throwing up hillocks, prepare the ground for seeds of various kinds. Seas, lakes, and rivers, by their streams and currents, often convey seeds unhurt to distant countries.
In assimilating the animal and vegetable kingdoms, Lin-nseus denominates seeds the eggs of plants. The fecundity of plants is frequently marvellous: from a single plant or stalk of Indian Turkey wheat, are produced, in one summer, 2000 seeds; of elecampane, 3000; of sun-flower, 4000; of poppy, 32,000; of a spike of cat's-tail, 10,000 and upwards: a single fruit or seed-vessel of tobacco, contains 1000 seeds; that of white poppy, 8000. Mr. Ray relates, from experiments made by himself, that 1012 tobacco seeds are equal in weight to one grain; and that the weight of the whole quantum of seeds in a single tobacco plant, is such as must, according to the above proportion, determine their number to be 360,000. The same author estimates the amual produce of a single stalk of spleen-wort to be upwards of 1,000,001 of seeds.
 
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