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However, we need not be at a loss; this Helianthus, or annual sunflower, is not only
"True as the dial to the sun,
Although it be not shone upon;"
but enables us to form some estimate of the hour, even when the great luminary is invisible-an advantage which we cannot obtain from the dial. See, its large radiated disc already inclines westward, whence we may be sure that the afternoon has commenced it will follow the setting sun, and at night, by its natural elasticity, will again return to the east, to meet the morning sun-beams. It was thought, that the heat of the sun, by contracting the stem, occasioned the flower to incline towards it; but the sensibility to light seems to reside in the radiated florets, as other similarly formed flowers, such as several of the Aster tribe, the daisy, marigold, &c. exhibit the same tendency, though not in so striking a manner. Many leaves likewise follow the sun, of which a clover-field affords a familiar instance. But the flowers we have enumerated, as they resemble the sun in their form, seem to have a secret sympathy with its beams, in absence of which some will not expand their blossoms at all; while on hot cloudless days they absorb such a quantity of light, that they emit it again in the evening in slight phosphoric flashes. These scintillations were first observed to proceed from the Garden Nasturtion: subsequently M. Haggren, of Sweden, perceiving faint flashes repeatedly darting from a Marigold, extended his ex
aminations, and stated, as the result, that the following flowers emitted flashes more or less vivid, in this order: the Marigold; Garden Nasturtion; Orange Lily; African Marigold; Annual Sun-flower. Bright yellow, or flame colour, seemed in general necessary for the production of the light, for it was never seen on flowers of any other hue. It would have been well if every plant possessed as appropriate a name as the Helianthus; and if Ovid, in his notice. of this flower, had always been equally fortunate in adapting botanical qualities to poetical purposes.
Nature has provided us with various substitutes for watches besides the Sunflower, many others opening and shutting their petals at certain hours of the day, thus constituting what Linnæus calls the horologe, or watch of Flora. He enumerates forty-six which possess this kind of sensibility, dividing them into, 1st, Meteoric flowers, which expand sooner or later, according to the cloudiness, moisture, or pressure of the atmosphere. 2dly, Tropical flowers, opening in the morning and closing in the evening, earlier or later as the length of the day increases or diminishes. 3dly, Equinoctial flowers, which open at a certain and exact hour of the day, and, for the most part, close at another determinate hour. We need not give the list, but can refer to their respective hours of rising and setting, if we encounter any of them in our rambles.
Observe this Pear-tree; in its wild state it has strong thorns, which have entirely disappeared from culture, whence Linnæus denominates such plants
tamed, or deprived of their natural ferocity, as wild animals sometimes lose their horns by domestication. The analogy between vegetable and animal life approaches much nearer than is generally imagined. Recent observation has traced the progress of the sap, from its first absorption by the roots, through the central vessels of the plant, into the annual shoot, leafstalk, and leaf, whence it is returned, and, descending through the bark, contributes to the process of forming the wood; thus describing a course, and fulfilling functions, very nearly correspondent to the circulation of the blood. There is something equivalent to respiration through the whole plant, the leaves principally performing the office of the lungs-it has one series of vessels to receive and convey the alimental juices, answering to the arteries, veins, &c. of animals; and a second set of trachea, wherein air is continually received and expelled. It absorbs food regularly, both from the earth and the atmosphere, converting the most vitiated effluvia, in the process of digestion, into the purest air. The vegetable and animal parts of creation are thus a counterbalance to each other, the noxious parts of the one proving salutary food to the other. From the animal body certain effluvia are continually passing off, which vitiate the air, and nothing can be more prejudicial to animal life than their accumulation; while, on the other hand, nothing can be more favourable to vegetables than these very effluvia, which they accordingly absorb with great avidity, and convert into the purest air. Plants are provided
with muscles, by which they open and shut their flowers, turn their leaves to the sun, even if they have been repeatedly folded back from it, and perform more complicated motions, as may be witnessed in the sensitive plants, the Dionæa Muscipula (or Fly-trap), and many others; nor have calm and reflecting writers been wanting who strenuously maintain the doctrine of a perceptive power in vegetables. As Corallines, Madrepores, and Sponges, formerly considered as fossil bodies or maritime plants, have by subsequent investigations been raised to the rank of animals, Dr. Percival does not consider it extravagant to suppose that, at some future period, perceptivity may be discovered to extend even beyond the limits now assigned to vegetable life.* A Hopplant turning round a pole follows the course of the sun, and soon dies when forced into an opposite line of motion; but remove the obstacle, and the plant quickly returns to its former position. When the straight branches of a Honeysuckle can no longer support themselves, they strengthen themselves by becoming spiral: when they meet with other branches of the same kind, they coalesce for mutual support, and one spiral turns to the right, one to the left; thus increasing the probability of their finding support by the diversity of their course. Lord Kames relates, that among the ruins of New Abbey, in Galloway, "there grows on the top of a wall a plane-tree twenty feet high. Straitened for nourishment, it several
* Manchester Transactions, Vol. II.
years ago directed roots down the side of the wall, till they reached the ground, ten feet below: and now the nourishment it afforded to those roots, during the time of descending, is amply repaid, having every year since that time made vigorous shoots."-If a plant be placed in a room which has no light except from a hole in the wall, it will shoot towards the hole, pass through it into the open air, and then vegetate upwards in its natural direction. Even in the profoundest calm, the leaves of the Hedysarum gyrans are in perpetual spontaneous motion; some rising, and others falling, and others whirling circularly by twisting their stems. From these and other evidences of spontaneity, Dr. Percival infers that vegetables have a limited degree of sensation and enjoyment; that they have an inferior participation in the common allotment of vitality; and thus that our great Creator hath apportioned good to all things, "in number, weight, and measure."
Leaving these physiological researches to those who are more competent to discuss them, let us resume our desultory notices as we sit beneath this Laburnum; and, as we cannot record many poetical phrases of the Dutch, let us not omit to mention that they call this tree, with not less fancy than propriety, the Golden Rain. Was it from one of these trees that Jupiter climbed to the window of the brazen tower in which Danaë was confined, and thus gave rise to the fable of his visiting her in a golden shower? -Fix your eyes steadfastly upon the cup of this Narcissus growing at our feet, and by suffering your