« 前へ次へ »
WALKS IN THE GARDEN.
"The life and felicity of an excellent gardener is preferable to all other diversions." EVELYN.
"What could I wish that I possess not here?
Health, leisure, means to improve it, friendship, peace,
"I Do dearly love," says the young lady in the comedy, "to see the dingy little sparrows in London hopping about from lamp-post to lamp-post."-" Talk of the rain," exclaims Mrs. Briggs, "pattering on the green leaves, and the birds chirping on the spray-give me the rain pattering on the green umbrellas, and the clink of pattens on the pavement!" Now, with due deference to these authorities, I cannot help thinking there is something very melancholy in the smoky aspect of those feathered cockneys, who are conversant with lamp-posts and the rumbling of cart-wheels, instead of the dancing green bough, and the music of the grove, or its hushing silence:-and, as to the effect of a shower in the country, I declare I do not know a more exhilarating sight, to say nothing of its melodious sounds and refreshing odours. To me the branches of the trees always appear to stretch themselves out, and droop their leaves with an obvious sense of enjoyment, while they are fed by the renovating moisture. I have been complacently watching my shrubs and plants during this repast;-but the rain is now over, they have finished their meal, and as they have already begun with fresh spirits to dance in the breeze and glitter in the sunshine, let us sally forth to share their festivity. What a delicious fragrance gushes from the freshened grass and borders! It is the incense which the grateful earth throws up to heaven in return for its fertilizing waters. Behold! here is one of the many objects which the shower has accomplished: by moistening the wings of the flying Dandelion, it has conveyed it to the earth at the very moment when it was best adapted for the reception of its seed. "The various modes by which seeds are dispersed, cannot fail to strike an observing mind with admiration. Who has not listened in a calm and sunny day to the crackling of furze bushes, caused by the explosion of their little elastic pods; or watched the down of innumerable seeds floating on the summer breeze, till they are overtaken by a shower, which, moistening their wings, stops their further flight, and at the same time accomplishes its final object, by immediately promoting the germination of each seed in the moist earth? How little are children aware, as they blow away the seeds of Dandelion, or stick burs in sport upon each other's clothes, that they are fulfilling one of the great ends of nature!"* The various mechanism and contrivances for the dis
* Smith's Introduction to Botany, p. 302.
semination of plants and flowers are almost inexhaustible. Some seeds are provided with a plume like a shuttlecock, which, rendering them buoyant, enables them to fly over lakes and deserts, in which manner they have been known to travel fifty miles from their native spot. Others are dispersed by animals, some attaching themselves to their hair or feathers by a gluten, as Misletoe; others by hooks, as Burdock and Hounds-tongue; and others are swallowed whole, for the sake of the fruit, and voided uninjured, as the Hawthorn, Juniper, and some grasses. Other seeds again disperse themselves by means of an elastic seed-vessel, as Oats and Geranium; and the seeds of aquatic plants, and those which grow on the banks of rivers, are carried many miles by the currents into which they fall. The seeds of Tillandsia, which grows on the branches of trees like Misletoe, are furnished with many long threads on their crowns, which, as they are driven forwards by the winds, wrap round the arms of trees, and thus hold them fast till they vegetate. When the seeds of the Cyclamen are ripe, the flower-stalk gradually twists itself spirally downwards till it touches the ground, and forcibly penetrating the earth, lodges its seeds, which are thought to receive nourishment from the parent root, as they are said not to be made to grow in any other situation. The subterraneous Trefoil has recourse to a similar expedient, which however may be only an attempt to conceal its seeds from the ravages of birds; while the Trifolium Globosum adopts a still more singular contrivance: its lower florets only have corols, and are fertile; the upper ones wither into a kind of wool, and, forming a head, completely conceal the fertile calyxes. But the most curious arrangement for vegetable locomotion, is to be found in the awn or beard of barley, which, like the teeth of a saw, are all turned towards one end of it: as this long awn lies upon the ground, it extends itself in the moist air of night, and pushes forward the barley-corn which it adheres to; in the day it shortens as it dries, and as these points prevent it from receding, it draws up its pointed end, and thus, creeping like a worm, will travel many feet from its parent stem. The late Mr. Edgeworth constructed a wooden creeping hygrometer upon this principle, which expanding in moist weather, and contracting itself when it was dry, in a month or two walked across the room, which it inhabited.
If Nature have been thus ingenious in providing for the dispersion of seeds, she has not been less provident in her arrangements for procuring a prolific and inexhaustible supply. Her great leading principle seems to be eternal destruction and reproduction, which one of our essayists tells us may be simplified into the following concise order to all her children, “eat and be eaten." She has been not less prodigal in the seeds of
* Darwin's Loves of the Plants, Canto 1.
plants than in the spawn of fish; as almost any one plant, if all its seeds should grow to maturity, would in a few years alone people the terrestrial globe. The seeds of one Sunflower amount to 4000; Poppy has 32,000. Mr. Ray asserts that 1012 seeds of Tobacco weighed only one grain, and that thus calculated, they amounted in one plant to 360,000; and he supposes the seeds of the Ferns to exceed a million on a leaf! Nor does this exuberance seem necessary to counteract their small tenacity of life, for, on the contrary, the vital principle in seeds is generally preserved with a remarkable vigour. Great degrees of heat, short of boiling, do not impair their vegetative power, nor do we know any degree of cold which has such an effect. They may be sent round the world, exposed to every variety of climate, without injury; and even when buried for ages deep in the ground, they retain their vitality, although they will not germinate, apparently from the want of some action of the air, as it has been ascertained by repeated experiments that seeds planted in the exhausted receiver of an air-pump will not vegetate. The earth thrown up from the deepest wells, although all possible access of fresh seeds be carefully excluded, will, upon exposure to the air, shoot forth weeds, grasses, and wild flowers, whose seeds must have lain dormant for many centuries; and it is very common, upon digging deeper than usual in gardener's grounds, to recover varieties of flowers which had long been lost.
Observe in this beautiful double Dahlia how highly nature may be improved, all double flowers being produced by cultivation, although their reproductive powers are frequently lost in the process, whence they have been termed by botanists vegetable monsters. This operation is effected in various ways: in some the petals are multiplied three or four times, without excluding the stamens, whence they are able to produce seeds, as in Campanula and Stramoneum; but in others the petals become so numerous as totally to exclude the stamens, and these are, of course, unproductive. In some the nectaries are sacrificed for the formation of petals, as in Larkspur; while in others the nectaries are multiplied to the exclusion of the petals, as in Columbine.
"Who loves a garden, loves a greenhouse too,"
sings Cowper; and ours, humble as it is, may afford us some instruction, as we sit and contemplate its evergreen inhabitants, filling their little amphitheatre in due succession of rank and dignity.
"Foreigners from many lands,
They form one social shade, as if convened,
These Vine-leaves, which were suspended yesterday by a thread with their under surfaces turned towards the windows, have already recovered their natural position, although detached from
the stem; whence we not only learn that light acts beneficially upon the upper surface, and injuriously upon the under side of leaves, but we have proof that the turning is effected by an impression made upon the leaf itself, and not upon the footstalk. Fruit-trees on the opposite sides of a wall invariably turn their leaves from the wall in search of light, which seems to have a positive attraction for them, exclusive of any accompanying warmth; for plants in a hot-house present the fronts of their leaves, and even incline their branches to the quarter where there is most light, not to that where most air is admitted, nor to the flue in search of heat. Light gives the green colour to leaves; for plants raised in darkness are of a sickly white, of which the common practice of blanching Celery in gardens, by covering it up with earth, is a proof under every one's observation. By experiments made with coloured glasses, through which light was admitted, it appears that plants become paler in proportion as the glass approaches nearer to violet.
This annual Mesembryanthemum would have afforded us another illustration of the extraordinary provisions of Nature for the dispersion of seed. It is a native of the sandy deserts of Africa, and its seed-vessels only open in rainy weather, otherwise the seeds in that country might lie long exposed before they met with sufficient moisture to vegetate. Succulent plants, which possess more moisture in proportion as the soil which they are destined to inhabit is parched and sunny, attain that apparently contradictory quality by the great facility with which they imbibe, and their being almost totally free from perspiration, which in plants of other latitudes is sometimes excessive. According to Dr. Hales, the large annual Sunflower perspires about seventeen times as fast as the ordinary insensible perspiration of the human skin; and the quantity of fluid which evaporates from the leaves of the Cornelian Cherry in the course of twenty-four hours, is said to be nearly equal to twice the weight of the whole shrub. Sometimes, from a sudden condensation of their insensible evaporation, drops of clear water will, even in England, in hot calm weather, fall from groves of Poplar or Willow, like a slight shower of rain. Ovid has made a poetical use of this exudation from Lombardy Poplars, which he supposes to be the tears of Phaeton's sisters, who were transformed into those trees.
How utterly vain and insignificant appear all the alembics and laboratories of chemists and experimental philosophers when compared with the innumerable, exquisite, and unfathomable processes which Nature in silence, and without effort, is at this instant elaborating within the precincts of our little garden! From the same mysterious earth, planted in the same pot, her inscrutable powers will not only concoct various flowers utterly
dissimilar in form, odour, colours, and properties, some perhaps containing a deadly poison, others a salutary medicine; but she will even sometimes combine all these discordant secretions in the same plant. The gum of the Peach-tree, for instance, is mild and mucilaginous. The bark, leaves, and flowers abound with a bitter secretion of a purgative and rather dangerous quality. The fruit is replete not only with acid, mucilage, and sugar, but with its own peculiar aromatic and highly volatile secretion, elaborated within itself, on which its fine flavour depends. How far are we still from understanding the whole anatomy of the vegetable body, which can create and keep separate such distinct and discordant substances !* Iron has been detected in roses, and is supposed to be largely produced by vegetable decomposition from the chalybeate quality and ochrous deposit of waters flowing from morasses; and it is well ascertained that pure flint is secreted in the hollow stem of the bamboo, in the cuticle of various grasses, in the cane, and in the rough horsetail, in which latter it is very copious, and so disposed as to make a natural file, for which purpose it is used in our manufactures. What a contrast, exclaims the same ingenious botanist, to whom we have been so largely indebted, between this secretion of the tender vegetable frame, and those exhalations which constitute the perfume of flowers! One is among the most permanent substances in nature, an ingredient in the primæval mountains of the globe; the other the invisible, intangible breath of a moment!
Among the innumerable advantages to be derived from a knowledge of botany, however slight, may be mentioned the perpetual amusement which it affords in scenes which to others might be only productive of ennui; the impressions of pure natural religion which it awakens, and the lofty and ennobling sentiments by which they are invariably associated. Nor do we need for this purpose the garden's artificial embellishments, as the same sensations may be excited, even in a more striking degree, amid the most desolate scenes.—
Nature in every form is lovely still.
I be not bower'd in a rustling grove,
Tracing through flowery tufts some twinkling rill,
And harking to the warbling breaks above.
Smith's Introduction to Botany.