An Encyclopædia of Agriculture

flower is then said to be luxuriant; and comprises the three following varieties: the multiplicate, the full, and the proliferous flower.

1612. The multiplicate flower is sometimes, though rarely, occasioned by an unusual multiplication of the divisions of the calyx, as in Diánthus Caryophyllus, and some of the alpine grasses. But the anomaly most generally consists in the undue multiplication of the divisions of the corolla, by the conversion of part of the stamens into petals, which is occasionally to be met w th both in monopetalous and polypetalous flowers. It occurs but seldom, however, in flowers growing in their natural state and habit, though now and then a double flower is met with even in such circumstances.

1613. The full flower is generally described to be that in which the divisions of the corrolla are so multiplied as to exclude the stamens and pistils wholly by means of their conversion into petals; which conversion is most readily effected in polypetalous flowers, such as the tulip, poppy, pink, and ranunculus; monopetalous flowers seldom being found full. This complete metamorphosis is always either the effect of cultivation, or of some concurrence of natural circumstances analogous to it, and is indeed one of the principal objects of the art of the florist; the heauty of the flower, according to general estimation, being thus much augmented. In the full flower the stamens are almost always converted into petals, whence we should perhaps infer their identity of origin. But the pistil is often converted into a leaf, as may be seen by inspecting the flower of the double-blossomed cherry, which generally protrudes from the centre a leaf in miniature. But a flower may become full also by the multiplication of the parts of the nectary, as is sometimes the case in the genus Aquilegia, which produces full flowers in three different ways: by the multiplication of the petals to the exclusion of the nectaries; by the multiplication of the nectaries to the exclusion of the petals; and by the multiplication of the nectaries while the proper petals remain. There are also some peculiarities in the manner in which compound flowers become full. Radiated flowers become full sometimes by the multiplication of the floscules of the ray to the exclusion of the floscules of the disk, as in Helianthus, A'nthemis, and Centaurèa; and sometimes by the multiplication of the floscules of the disk to the exclusion of those of the ray, as in Matricària and Béllis.

1614. The proliferous flower (fig. 193.) is that out of which another flower or another shoot is produced. It is seldom found but in flowers already full; from the centre of which, that is, from the ovary or pistil, it sometimes happens that a new flower and foot-stalk is produced, if the flower is simple, as in the ranunculus, anemone, and pink; or several flowers and foot-stalks issuing from the common calyx, if the flower is compound, as in the daisy, hawkweed, and marigold; or a new umbel issuing from the centre of the original umbel, if the flower is umbellate, as in Córnus.

1615. Various anomalies. Sometimes the proliferous issue of the full flower is not itself a flower, but a shoot furnished with leaves, as has been sometimes, though rarely, observed in the case of the anemone and rose. Such are the several varieties of luxuriant flowers, constituting anomalies of excess: but it sometimes happens that there is also in the flower an anomaly of defect in the absence of one of its parts. Examples of this sort are occasionally to be met with in the flowers of Cheiranthus Cheiri, Campanula pentagònia, and Tussilago anándria, in which the corolla is altogether wanting, though proper to the species; and in this case the flower is said to be mutilated. Sometimes the anomaly consists in the situa tion of the flower, which is generally protruded from the extremity or sides of the branches; but the flower of the Rúscus is protruded from the surface of the leaf. Or it may consist in the relative situation of the several parts of the flower. In simple flowers, the pistil is invariably central with regard to the stamens ; but in compound flowers the pistils are often situated in the circumference and the stamens in the centre. This seems to be the case, also, with some monoecious plants, having their flowers on the same peduncle, as in the example of the Carex and Arum, in which the stamens are more central than the pistils. Sometimes the anomaly consists in the color of the corolla, which will often deviate even in the same species. The general colour of the common cowslip (Primula vèris) is a bright yellow; but an individual is occa sionally to be met with, though very rarely, in which the limb or expansion of the corolla is purple with a line of yellow around the border. Sometimes the anomaly consists in the time of flowering. The season proper for the flowering of the apple and pear tree is the month of May; but trees of that sort have been known to protrude both buds and blossoms even in the month of November. Some plants, however, blow only in the winter, as in the case of the laurustinus and Arbutus Unèdo; while others blow only in the night, and refuse to expand their petals to the light of the sun. Such is the case of the Cactus grandiflora, that produces one of the most magnificent of flowers, but blows only in the night; and is hence known also by the appellation of the night-blowing cereus. Some plants, such as the A'lgæ, and Fúngi, are altogether destitute of conspicuous flowers; and are hence called Cryptogamous. The flower of the fig is perhaps one of the most singular in respect of concealment. The flowers of perfect plants, which, in other cases, uniformly precede the fruit, are in this case concealed within what is generally denominated the fruit; as may be proved by cutting open a green fig (fig. 194.) by means of a longitudinal section passing through its axis. Great numbers of flowers are then discovered lining a sort of cavity in the axis of the fruit; and hence what is called the fruit or fig, in common language, is rather the receptacle of the flower than any thing

else. Most plants have their flowers furnished both with stamens and pistils, and are hence hermaphro dites. But there are also many genera that have the stamens in one flower and the pistils in another, both on the same individual: these are denominated Monoecious plants, and are exemplified in the oak and hazel. Other genera have the flowers with stamens on one plant, and the flowers with pistils on another: these are denominated Diacious, and are exemplified in the hop and willow. Others have unisexual flowers of each kind on one and the same plant, as in Moncecia; on separate plants, as in Dicecia; and on others mixed with those which are hermaphrodite: these are denominated Polygamous, and are exemplified in the genus A'triplex. In a species of Euterpe, found on the island of Bourbon, the flowers are visible eight years before they are expanded. The summit is formed of twelve leaves, each supplied with a bunch of flowers in its axilla. Three leaves only expand each year, so that four years will have elapsed between the expansion of the first flowers and of the last, although even the former were discoverable four, and the latter eight, years previously. (London Encyc., art. Botany.)

1616. The fruit. The anomalies of the fruit may affect either its number, figure, colour, or appendages.

1617. The common hazel-nut produces in general but one kernel in one shell; but in the course of opening a considerable number, you will now and then meet with one containing two or three kernels in a shell. This is, perhaps, best accounted for by supposing, with Du Hamel, that it is the result of an unnatural graft effected in the bud; though some think that the shell does always contain the rudiments of

two or more kernels, although it rarely happens that more than one is developed. But if two apples or

pears are developed in an incorporated state, which is a case that now and then occurs, it is no doubt best accounted for by the graft of Du Hamel. Sometimes the anomally consist in the figure of the fruit, which is deformed by tumours or excrescences, in consequence of the bite of insects, or injuries of weather producing warts, moles, or specks. Sometimes it consists in the colour, producing green melons and white cucumbers. Sometimes it consists in an appendage of leaves. (fig. 195.)

1618. Habit. The anomalies of habit are principally occasioned by soil and cultivation.

1619. Some plants, which, when placed in a rich soil, grow to a great height, and affect the habit of a tree, are, when placed in a poor soil, converted into dwarfish shrubs. This may be exemplified in the case of the box-tree; it also occurs in the case of herbaceous plants; as in that of Myosotis, which in dry situations is but short and dwarfish, while in moist situations it grows to such a size as to seem to be altogether a different plant. The habit of the plant is sometimes totally altered by means of cultivation: the Pyrus sativa, when growing in a wild and uncultivated state, is furnished with strong thorns; but when transferred to a rich and cultivated soil the thorns disappear. This phenomenon, which was observed by Linnæus, was regarded as being equivalent to the taming of animals: but this explication is, like some others of the same great botanist, much more plausible than profound, in place of which Professor Willdenow substitutes the following; the thorns protruded in the uncultivated state of the plant, are buds rendered abortive from want of nourishment, which when supplied with a sufficiency of nourish. ment are converted into leaves and branches.

1620. Physical virtues. When plants are removed from their native soil and taken into a state of culture, it alters not only their habit but their physical virtues. Thus the sour grape is rendered sweet; the bitter pear, pleasant; the dry apricot, pulpy ; the prickly lettuce, smooth; and the acrid celery, wholesome. Potherbs also are rendered more tender, by means of cultivation, and better fitted for the use of man; and so are all our fine fruits. 1621. Duration. Plants are either annuals, biennials, or perennials, and the species is generally of the same duration in every climate. But it has been found that some plants, which are annuals in a cold climate, such as that of Sweden, will become perennials in a hot climate, such as that of the West Indies; this anomaly has been exemplified in Tropa olum, beet root and Málva arbòrea: and, on the contrary, some plants, which are perennials in hot climates, are reduced to annuals when transplanted into a cold climate; this has been exemplified in the climbing kidney beans.

SECT. VI. Of the Sexuality of Vegetables.

1622. The doctrine that plants are of different sexes, and which constitutes the foundation of the Linnean system, though but lately established upon the basis of logical induction, is by no means a novel doctrine. It appears to have been entertained even among the original Greeks, from the antiquity of their mode of cultivating figs and palms. Aristotle and Theophrastus maintained the doctrine of the sexuality of vegetables; and Pliny, Dioscorides, and Galen adopted the division by which plants were then distributed into male and female; but chiefly upon the erroneous principle of habit or aspect, and without any reference to a distinction absolutely sexual. Pliny seems to adirit the distinction of sex in all plants whatever, and quotes the case of a palm tree as exhibiting the most striking example.

1 Linnæus, reviewing with his usual sagacity the evidence on which the doctrine rested, and per. ceiving that it was supported by a multiplicity of the most incontrovertible facts, resolved to devote his labours peculiarly to the investigation of the subject, and to prosecute his enquiries throughout the whole extent of the vegetable kingdom; which great and arduous enterprise he not only undertook, but accomplished with a success equal to the unexampled industry with which he pursued it. So that by collecting into one body all the evidence of former discovery or experiment, and by adding much that was original of his own, be found himself at length authorised to draw the important conclusion, that no seed is perfected without the previous agency of the pollen, and that the doctrine of the sexes of plants is consequently founded in fact.

164 Proofs from the economy of the aquatics. Many plants of this class which vegetate for the most part wholly immersed in water, and often at a considerable depth, gradually begin to elevate their stems as the season of flowering advances, when they at last rear their heads above the surface of the water, and present their opening blossoms to the sun, till the petals have begun to fade, after which they again gradually sink down to the bottom to ripen and to sow their seeds. This very peculiar economy may be exemplified in the case of Ruppia maritima, and several species of Potamogeton common in our ponds and ditches From this we may fairly infer, that the Bowers rise thus to the surface merely to give the pollen an opportunity of reaching the stigma uninjured. But the most remarkable example of this kind is the Vallisèria spiralis (fig 196), a plant which grows in the ditches of Italy. The plant is of the class Dice cia, producing its fertile flowers on the extremity of a long and slender stalk (a) twisted spirally like a corkscrew, which uncoiling of its own accord, about the time of the opening of the blossom, elevates the flowers to the surface of the water, and leaves them to expand in the open air. The barren flowers (6) are produced in great numbers upon short upright stalks issuing from a different root, from

the 50 stamens of Barringtònia, the 230 of Thea, and the 80 of the Caryophyllus fecundate only two or three ovules.

SECT. IX. The Propagation of the Species.

1639. As the life of the vegetable, like that of the animal, is limited to a definite period, and as a continued supply of vegetables is always wanted for the support of animals, what we call art, or nature operating by means of the animal man, has taken care to institute such means as shall secure the multiplying and perpetuating of the species in all possible cases.

1640. Equivocal generation. It was long a vulgar error, countenanced even by the philosophy of the times, that vegetables do often spring up from the accidental mixture of earth and putrid water, or other putrid substances, in the manner of what was called the equivocal generation of animals; or, at the very least, that the earth contains the principle of vegetable life in itself, which, in order to develope, it is only necessary to expose to the action of the air. The former alternative of the error has been long ago refuted; the latter has lost its hold, having been refuted by Malpighi, who proved that the earth produces no plant without the intervention of a seed, or of some other species of vegetable germ deposited in it by nature or by art.

1641. Propagation by seeds. When the seed has reached maturity in the due and regular course of the developement of its several parts, it detaches itself sooner or later from the parent plant, either singly or along with its pericarp, and drops into the soil, where it again germinates and takes root, and springs up into a new individual. Such is the grand means instituted by nature for the replenishing and perpetuating of the vegetable kingdom.

from the plant or pericarp. This spiral awn or spring, which is beset with a multitude of fine and minute hairs, possesses the property of contracting by means of drought, and of expanding by means of moisture. Hence it remains of necessity in a perpetual state of contraction or dilatation, dependent upon change of weather; from which, as well as from the additional aid of the fine hairs, which act as so many fulcra, and cling to whatever object they meet, the seed to which it is attached is kept in continual motion till it either germinates or is destroyed. The awn of barley, which is beset with a multitude of little teeth all pointing to its upper extremity, presents also similar phenomena. For when the seed with its awn falls from the ear and lies flat upon the ground, it is necessarily extended in its dimensions by the moisture of the night, and contracted by the drought of the day but as the teeth prevent it from receding in the direction of the point, it is consequently made to advance in the direction of the base of the seed, which is thus often carried to the distance of many feet from the stalk on which it grew. If any one is yet sceptical with regard to the travelling capacity of the awn, let him only introduce an awn of barley with the seed uppermost between his coat and shirt sleeve at the wrist, when he walks out in the morning, and by the time he returns to breakfast, if he has walked to any great distance, he will find it up at his armpit. This journey has been effected by means of the continued motion of the arm, and consequently of the teeth of the awn acting as feet to carry it forward.

1643. Where distance of dispersion is required, nature is also furnished with a resource. One of the most common modes by which seeds are conveyed to a dis tance from their place of growth is that of the instrumentality of animals. Many seeds are thus carried to

a distance from their place of growth, merely by their attaching themselves to the bodies of such animals as may happen accidentally to come in contact with the plant, in their search after food; the hooks or hairs with which one part or other of the fructification is often furnished, serving as the medium of attachment, and the seed being thus carried about with the animal till it is again detached by some accidental cause, and at last committed to the soil This may be exemplified in the case of the Bidens and Myosotis, in which the hooks or prickles are attached to the seed itself, or in the case of Galium Aparine and others, in which they are attached to the pericarp; or in the case of the thistle and the burdock, in which they are attached to the general calyx. Many seeds are dispersed by animals in consequence of their pericarps being used as food. This is often the case with the seeds of the drupe, as cherries and sloes, and with the berries of the hawthorn, which birds often carry away till they meet with some convenient place for devouring the pulpy percarp, and then drop the stone into the soil. And so also fruit is dispersed that has been hoarded for the winter, though even with the view of feeding on the seed itself, as in the case of nuts hoarded up by squirrels, which are often dispossessed by some other animal, which, not caring for the hoard, scatters and disperses it. Sometimes the hoard is deposited in the ground itself, in which case part of it is generally found to take root and to spring up into plants; though it has been observed that the ground squirrel often deprives the kernel of its germ before it deposits the fruit it collects. Rooks have been also observed to lay up acurus and other seeds in the holes of fence-posts, which being either forgot or accidentally thrust out, fall ultimately into the earth and germinate. But sometimes the seed is even taken into the stomach of the animal, and afterwards deposited in the soil, having passed through it unhurt. This is often the case with the seed of many species of berry, such as the mistletoe, which the thrush swallows and afterwards deposits upon the boughs of such trees as it may happen to alight upon. The seeds of the Loranthus americanus, another parasitical plant, are said to be deposited in like manner on the branches of the Coccoloba grandiflora and other lofty trees; as also the seeds of Phytolacca decandra, the berries of which are eaten by the robin, thrush, and wild pigeon. And so also the seeds of currants or roans are sometimes deposited, after having been swallowed by blackbirds or other birds, as may be seen by observing a currant bush or young roan tree growing out of the cleft of another tree, where the seed has been left, and where there may happen to have been a little dust collected by way of soil; or where a natural graft may have been effected by the insinuation of the radicle into some chink or cleft. It seems indeed surprising that any seeds should able to resist the heat and digestive action of the stomach of animals; but it is undoubtedly the fact. Some seeds seem even to require it. The seeds of Magnolia glaúca, which have been brought to this country, are said generally to have refused to vegetate till after undergoing this process, and it is known that some seeds will bear a still greater degree of heat without any injury. Spallanzani mentions some seeds that germinated after having been boiled in water: and Du Hamel gives an account of some others that germinated even after having been exposed to a degree of heat measuring 35 of Fahrenheit. In addition to the instrumentality of brute animals in the dispersion of the seed might be added also that of man, who, for purposes of utility or of ornament, not only transfers to his native soil seeds indigenous to the most distant regions, but sows and cultivates them with care. "A farmer in the West of Scotland has been in the practice, for some years, of feeding his cows upon potato-apples, and using their dung, and raising seedling plants from it the seeds; having passed through the stomach of the cos, without having undergone such a change as to prevent them from vegetating." (Note of Mr. Cleghorn, Ed. of the Edinburgh Farm. Mag.)

1644. The agency of winds is one of the most effective modes of dispersion instituted by nature. Some seeds are fitted for this mode of dispersion from their extreme minuteness, such as those of the mosses, Lichens and Fungi, which float invisibly on the air, and vegetate wherever they happen to meet with a suitable soil. Others are fitted for it by means of an attached wing, as in the case of the fir tree and Liriodendron tulipifera, so that the seed, in falling from the cone or capsule, is immediately caught by the wind, and carried to a distance. Others are peculiarly fitted for it by means of their being furnished with an aigrette or down, as in the case of the dandelion, goat's-beard, and thistle, as well as most plants of the Class Syngenèvia; the down of which is so large and light in proportion to the seed it supports, that it is wafted on the most gentle breeze, and often seen floating through the atmosphere in great abundance at the time the seed is ripe. Some have a tail, as in Clématis Vitálba. Others are fitted for this mode of dispersion by means of the structure of the pericarp, which is also wafted along with them, as in the case of Staphylea trifolia, the inflated capsule of which seems as if obviously intended thus to aid the dispersion of the contained seed, by its exposing to the wind a large and distended surface with but little weight; and so also in the case of the maple, elm, and ash, the capsules of which are furnished, like some seeds, with a membranous wing, which when they separate from the plant the wind immediately lays hold of and drives before it.

1645. The instrumentality of streams, rivers, and currents of the ocean, is a further means adopted by nature for the dispersion of the seeds of vegetables. The mountain-stream or torrent washes down to the valley the seeds which may accidentally fall into it, or which it may happen to sweep from its banks when it suddenly overflows them. The broad and majestic river, winding along the extensive plain, and traversing the continents of the world, conveys to the distance of many hundreds of miles the seeds that may have vegetated at its source. Thus the southern shores of the Baltic are visited by seeds which grew in the interior of Germany, and the western shores of the Atlantic by seeds that have been generated in the interior of America. But fruits indigenous to America and the West Indies have sometimes been found to be swept along by the currents of the ocean to the western shores of Europe, and even on the coasts of Orkney and Shetland. Fruits of Mimosa scándens, Stizolòbium prùriens, Guilandina Bónduc, and Anacardium occidentale, or cashew nut, have been thus known to be driven across the Atlantic to a distance of upwards of 2000 miles; and although the fruits now adduced as examples are not such as could vegetate on the coast on which they were thrown, owing to soil or climate, yet it is to be believed that fruits may have been often thus transported to climates or countries favourable to their vegetation.

1646 Propagation by gems. Though plants are for the most part propagated by means of seeds, yet many of them are propagated also by means of gems; that is, bulbs and buds.

1547. The caulinary bulb is often the means of the propagation of the species: it generally appears in the axils of the leaves, as in Dentària bulbifera and Lilium bulbiferum; or between the spokes of their uubels, as in Allium canadénse; or in the midst of the spike of flowers, as in Polygonum viviparum and Poa alpina. As plants of this last kind are mostly alpine, it has been thought to be an institution or resource of nature, to secure the propagation of the species in situations where the seed may fail to ripen. 1. The bud, though it does not spontaneously detach itself from the plant and form a new individual, will yet sometimes strike root and develope its parts if carefully separated by art and planted in the earth: but this is to be understood of the leaf-bud only, for the flower-bud, according to Mirbel, if so treated, always perishes.

1649 Propagation by the leaves. The species may sometimes be propagated even by means of the leaves, as in the aloe, Xylophylla, sea-onion, and some species of Arum; which if carefully deposited in the soil will grow up into new plants, by virtue, no doubt, of some latent gem contained in them. The Fungi and bchens, according to Gartner, are all gemmiferous, having no sexual organs, and no pollen impregnating a germ. In the genus Lycoperdon, the gelatinous substance that pervades the cellular tissue is converted into a proliferous powder; in Clavaria, the fluid contained in the cavities of the plant is converted into a Proliferous powder also; and in the agarics, Hypnum, and Boletus, vesicles containing soboliferous granules are found within the lamella, pores, or tubes. Hedwig, on the contrary, ascribes to the Fungi a sexual apparatus, and maintains that the pollen is lodged in the volva: but here it is to be recollected, as in the cases of the scutelle of the litchens, that all Fungi are not furnished with a volva, and consequently

the 50 stamens of Barringtonia, the 250 of Thea, and the 80 of the Caryophyllus fecundate only two or three ovules.

SECT. IX. The Propagation of the Species.

1640. Equivocal generation. It was long a vulgar error, countenanced even by the philosophy of the times, that vegetables do often spring up from the accidental mixture of earth and putrid water, or other putrid substances, in the manner of what was called the equivocal generation of animals; or, at the very feast, that the earth contains the principle of vegetable life in itself, which, in order to develope, it is only necessary to expose to the action of the air. The former alternative of the error has been long ago refuted; the latter has lost its hold, having been refuted by Malpighi, who proved that the earth produces no plant without the intervention of a seed, or of some other species of vegetable germ deposited in it by nature or by art.

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An Encyclopædia of Agriculture: Comprising the Theory and Practice of the ...