Cutting is a part of a plant capable of emitting roots, and of becoming an individual similar to its parent. The circumstances requisite to effect this are a suitable temperature and degree of moisture.

Cuttings in general may be taken either from the stem, branch, or root; and are, in fact, grafts, which by being placed in the earth, a medium favourable to the production of roots these emit, instead of aiding the stock to effect that development of vessels necessary for their union to it, had they been grafted. A due degree of moisture in the soil is absolutely required from it by cuttings, for these will often produce roots if placed in water only. The time for taking off cuttings from the parent plant for propagation, is when the sap is in full activity; the vital energy in all its parts is then most potent for the development of the new organs their altered circumstances require. Well-matured buds are found to emit roots most successfully, and apparently for the same reason that they are least liable to failure, when employed for budding, viz., that being less easily excitable, they do not begin to develop until the cutting has the power to afford a due supply of sap. Therefore, in taking a cutting, it is advisable to remove a portion of the wood having on it a bud, or joint, as it is popularly called, of the previous year's production.

Many plants can be multiplied by cuttings with the greatest difficulty, and after every care has been taken to secure to the cutting every circumstance favourable to the developement of roots.

Those plants which vegetate rapidly, and delight in either a moist or rich soil, are those which are propagated most readily by this mode, and such plants are the willow, gooseberry and pelargonium; a budded section of these can hardly be thrust into the ground without its rooting.

Cuttings of those plants which grow tardily, or in other words form new parts slowly, are those which are most liable to fail. These are strikingly instanced in the heaths, the orange, and cera-tonia.

A rooted cutting is not a new plant, it is only an extension of the parent, gifted with precisely the same habits, and delighting most in exactly the same degree of heat, light and moisture, and in the same food.

A cutting produces roots, either from a bud or eye, or from a callus resembling a protuberant lip, which forms from the alburnum between the wood and the bark round the face of the cut which divided the slip from the parent stem. If the atmospheric temperature is so high that moisture is emitted from the leaves faster than it is supplied, they droop or flag, and the growth of the plant is suspended. If a cutting be placed in water, it imbibes at first more rapidly than a rooted plant of the same size, though this power rapidly decreases; but if planted in the earth, it at no time imbibes so fast as the rooted plant, provided the soil is similarly moist; and this evidently because it has not such an extensive imbibing surface as is possessed by the rooted plant; consequently, the soil in which a cutting is placed should be much more moist than is beneficial to a rooted plant of the same species, and evaporation from the leaves should be checked by covering the cuttings with a bell-glass, or a Wardian case would be still better. The temperature to which the leaves are exposed should be approaching the lowest the plant will endure.

The warmer the soil within the range of temperature most suitable to the plant, the more active are the roots, and the more energetically are carried on all the processes of the vessels buried beneath the surface of the soil; 50° for the atmosphere, and between 65° and 75° for the bottom heat, are the most effectual temperatures for the generality of plants. The cutting should be as short as possible consistently with the object in view. Three or lour leaves, or even two, if the cutting be very short, are abundant. They elaborate the sap quite as fast as required, and are not liable to exhaust the cutting by super-exhalation of moisture.

Cuttings taken from the upper branches of a plant, flower and bear fruit the earliest, but those taken from near the soil are said to root most freely. Cuttings which reluctantly emit roots may be aided by ringing. The ring should be cut round the branch a few weeks before the cutting has to be removed; the bark should be completely removed down to the wood, and the section dividing the cutting from the parent be made between the ring and the parent stem, as soon as a callus appears round the upper edge of the ring.

The soil is an important consideration. The cuttings of orange trees and others which strike with difficulty if inserted in the middle of the earth of a pot, do so readily if placed in contact with its side. The same effect is produced by the end of the cutting touching an under drainage of gravel or broken pots. Why is this? My observations justify me in concluding that it is because in those situations, the side and the open drainage of the pot, the atmospheric air gains a salutary access. A light porous soil, or even sand, which admits air the most readily, is the best for cuttings; and so is a shallow pan rather than a flower pot, and apparently for the same reason. I have no doubt that numerous perforations in the bottom of the cutting pan would be found advantageous for cuttings which root slowly.

Some plants may be successfully propagated by means of the leaves, and among those whose numbers are thus most commonly increased, are the Cacti, Gcsnerae, Gloxinia;, and other fleshy leaved plants. Lately the suggestion has been revived, - a suggestion first made by Agricola at the commencement of the last century. He states that M. Manderola had raised a lemon-tree in this mode; and thence concludes, rather too rashly, that all exotic leaves may at any time be converted into trees. Since that was written, in 1721, it is certain that plants have been raised from leaves that previously had been considered totally incapable of such extension. Thus M. Neumann has succeeded with the Theophrasta latifolia; and going a step further, he has even bisected a leaf, and raised a leaf from each half.

Mr. Knight has also recorded in the Horticultural Transactions of 1822, that leaves of the peppermint (Mentha piperita), without any portion of the stem upon which they had grown, lived for more than twelve months, increased in size, nearly assumed the character of evergreen trees, and emitted a mass of roots. That leaves may be made almost universally to emit roots there appears little reason to doubt; for the same great physiologist had long before proved that the roots of trees are generated from vessels passing from the leaves through the bark; and that they never in any instance spring from the alburnum. But the question arises, will they produce buds V and at present the answer derived from practice is in the negative; orange leaves, rose leaves, leaves of Statice arborea, have been made to root abundantly; but like blind cabbage plants, they obstinately refused to produce buds.

Dr. Lindley thinks that a more abundant supply of richer food, and exposure to a greater intensity of light, would have removed this deficiency; and I see every reason for concurring with so excellent an authority; for buds seem to spring from the central vessels of plants, and these vessels are never absent from a leaf. If an abundant supply of food were given to a well-rooted leaf, and it were cut down close to the callus, from whence the roots are emitted, I think buds would be produced, for the very roots themselves have the same power.

In general, the young wood strikes most readily. Those of the Semecarpus mahogani, Swietenia mahogani, Euphorbia, litchi, and others, must have the wood quite soft, and must be inserted in the soil under bell-glasses the moment they are cut. On the contrary, cuttings of milky, gummy or resinous plants, such as Araucaria, Euphorbia, and Vahea gummifera, require to be buried in damp sand for twenty-four hours, with the wound exposed, and then to be planted, after having the exuded matter washed off with a sponge. Herbaceous plants having a partial developmentof wood, as the Pelargonium, Calceolaria, and Cineraria, will strike in any place shaded from the meridian sun. Cuttings of fleshy-leaved plants, as the Cacti, and many others, root better after being allowed to remain for forty-eight hours, after division from the parent plant, before they are planted. Diosmas, fuchsias, heaths, camellias, etc, require for their cuttings the gentle heat of a nearly exhausted hotbed, and a close atmosphere, with but little light admitted night and morning. The bell-glasses employed should be proportioned to the size of the cutting. A small cutting should not be placed under a large glass.

Blue and violet-coloured glass is found most favourable for the purpose, and this is accounted for by the fact, that glass of this colour admits very few luminous or leaf-stimulating rays of light; but nearly all the chemical rays of the spectrum, which assist in the decomposition of bodies. M. Neumann has succeeded in striking cuttings of monocotvle-donous plants, such as Draycena, Frey-cenettia, and Vanilla. The cuttings may be from branches of any age between less than one and six years old. They require to have the leaves cut away at the bottom of the cutting, the whole length of the portion to be buried. It is not necessary to use the extremities of branches, pieces from their middles answer as well. M. Neumann also thinks that all dicotyledonous plants may be multiplied by cuttings of their roots, or even by detached leaves. Dais cotinifolia is increased from cuttings of the roots, and so is Paulownia imperialis. Pieces two inches long, and half an inch in diameter, and cut in March, root well. Maclaura aurantiaca succeeds similarly even in the open air, the upper wound of the cutting being placed nearly level with the surface.

He has also multiplied Araucaria Cun-ninghami, and all the Coniferce, by root cuttings.

Soil

The soil most generally applicable, is that which is rich and light. Some cuttings, as those of the Tamarix elegans and T. germanica, require a little saltpetre in the soil.