Some of them follow the sun's apparent course, that is, from east to west,—and always twine around the stem which supports them in the direction of left to right. Such is the case with the common black briony, so common in our woods and groves.
Others invariably twine contrary to the sun, or from right to left; as is the case with the convolvulus, or large white bindweed.
This singular tendency, be it observed, is always constant in each individual of the species, and if you endeavour to train one of these plants in a different direction, you will infallibly kill it.
The convolvulus will not grow from left to right, and the black briony will not grow from right to left. Crede experto.
The convolvulus, or white bindweed (Convolvulus sepium, or Calystegia sepium), is one of the most elegant, though one of the commonest climbing plants which festoon our willows, or creep over our grassy banks, or wind in and about our hedges. Its large white bells, which the country people unpoetically call "old men's nightcaps," are remarkable for their purity of hue and exquisite beauty of outline; and the leaves, which are heart-shaped, equally claim our admiration. Like the pink field-convolvulus (Convolvulus arvensis), or the rosy-hued seaside bindweed (Calystegia soldanella), it is very tenacious of life, and if it once secures a footing, is eradicated with difficulty. Hence it is dearer to the poet and artist than to the farmer and gardener, each of whom pursues it with a determined hostility.
The Convolvulaceæ form a distinct family or order, containing forty-five genera, and upwards of seven hundred species. They are found in temperate and tropical countries; and include the dodder, sweet potato, scammony, spomœa, and the jalap plant.
Metamorphosis.—A Physico-Philosophical Meditation.[86]
If we are to understand by the term metamorphosis simply "a change," it is evident that everybody undergoes metamorphosis, is changed or transformed; nothing is, all becomes.
The water which flows on for ever, but never twice washes the same pebbly bed, will afford us an apt image of this perpetual "to become."
But even the said pebbly bed, like the hardest rock, like the seemingly everlasting granite, must and does change. The compact, chrystalline, azoic rock, without a trace of life in its dense mass, would eventually decompose if constantly assailed and affected by the moving waves of that gaseous ocean whose bed is formed by the terrestrial crust. If the rock is found covered by more or less stratified layers, its presence in the bosom of the earth will attest to passing generations the primordial incandescence of our planet at some epoch when life as yet was not,—when the liquid element, hurled far away into space under the form of vapour, exhibited the aspect of a "bearded meteor," or a comet, with blazing nucleus and incandescent tail. Many the changes which since that distant epoch have taken place upon the earth, and many more must occur before our planet ceases to contribute its strain to the grand harmony of the spheres. Our world will end as surely as it once had a beginning: its duration, though it be computed by hundreds of thousands of years, is nothing, will be nothing, compared with that of the revolution of yonder sun, circling, with its wondrous train of planets, around some mysterious centre as yet unknown. And in this period, hitherto incalculable, what chances of perturbation will necessarily arise?