So amenable are leaf-buds on stems to scientific treatment, that buds apparently dormant may be started, and set in motion, and become branches, by the simple plan, in the month of February, of cutting a notch with a fine saw in the bark just above it, so as to check the upward flow of the sap - the too rapid growth of the stem has caused the bud to be dormant - and arrest or divert some of it into the dormant leaf-bud, which will become a branch (in fact, a branch is only a developed leaf-bud). This is one of the many methods by which gardeners repair the loss of a branch where one has been lost on a pyramid tree, to give it symmetry.

Grafting is an operation at present confined to dicotyledonous plants, by means of which a portion of a plant containing one or more eyes or buds, called a scion or graft, is joined or inserted in another plant belonging to the same species, called the stock, and is effected in many different modes (not within the object of the writer to explain), such as by approach or inarching, or by detached scions, or by budding - that is bud-grafting - but the result is the same. After the union is perfected the growth of the scion takes place, and the stock henceforth bears the scion instead of one of its own growth, which has been cut off and removed. Grafting has not been successful with monocotyledonous plants.

One object of grafting is to change the permanent characters of the graft or scion, by improving the flavour of the fruit, or rendering it more productive, of which there is some doubt; though it would be easy to surmise that a difference between the contents of the cambium layer or of the cell-tissue of the foster-parent or stock and that of the graft or scion might alter or retard the growth of the scion, so as to cause the production of fruit-buds instead of leaf-buds. Another object of grafting is to restore an old worn-out tree by cutting off its branches and using the stem as the stock, and grafting on it a new scion or graft. Another object is to propagate and increase a larger number of trees - for instance, recent introductions into this country - by grafting scions of them on to older and less valuable trees, and so provide a larger number than would otherwise be possible to do except during a number of years. Another object of grafting may be to place on the same monoecious plant the two necessary organs of a perfect plant - namely, the stameniferous and pistilliferous flowers. It need hardly be observed, that after the union of the graft or scion with the stock is perfect, the individual characteristics of the graft or scion are preserved.

It is a popular fallacy that the blood-red Orange has been procured by grafting the Orange scion on the Pomegranate-tree.

By scientifically pruning fruit-trees in summer-time, buds which might otherwise remain leaf-buds are arrested and metamorphosed into fruit-buds; but fruit-buds, when once formed, can hardly be turned into leaf-buds, though they may be rendered abortive: and by improper treatment of a Vine, as by excess of moisture and heat, a crop of tendrils only may be produced instead of a crop of Grapes. And these cases are not difficult to understand when it is remembered that the different parts of a flower, even pistils and stamens, are only modifications of leaves, and that the tendril of the Vine is a modified flower peduncle - a continuation of the main axis. It is made up of a common peduncle, bearing two branches, - one is the flower tendril, always longer than the other branch, which is the flowering part or sub-peduncle. It is this sub-peduncle which is so easily modified, by improper treatment, into a tendril, however strange this behaviour may seem to be.

The flower-bud of mono- and di-cotyledonous plants, like the leaf-bud, consists of leaves placed at the extremity of the stem or branch of a plant, but so metamorphosed from the ordinary leaf-bud that it requires some attentive study to understand it. It is either sessile or placed on a simple stalk, called a peduncle, on the top of which is the receptacle on which some of the floral organs rest (this peduncle is sometimes curiously hollowed out, as in the flower of the Rose and Apple, and in the Fig it contains the flowers), or it is placed on a branched stalk called a pedicel. If we examine it, beginning at the outside, we have first, at the base of the peduncle, a whorl of leaves called bracts, not necessarily green (in Bougainvillea spectabilis, coloured), of which there are several kinds, from the simple forms to the more elaborate spathe of Arum; or if it is at the base of a pedicel, we shall have bracteoles or an involucre. Then come the floral whorls, generally four in number, consisting first of the calyx and its parts or pieces, called sepals (sepalline leaves), not necessarily green (in the Fuchsia, coloured); then comes the corolla, its parts called petals, also metamorphosed leaves: and here we must revert to the discoveries of Mr H. C. Sorby of the different kinds of pigments in leaf-structure, and notice that the law of continuity running through the leaf-structure of every plant, wherever found, will hold good in the corolla, and explain how pigments in the leaf may also show themselves in the petals of the corolla; and one is not surprised to hear that it has been said that the greater the metamorphosis of leaf-structure, as in an irregular flower, the more variation of colour and markings may be expected. (This may or may not be so.) Then come, in our examination, the stamens, which are still metamorphosed leaves (staminate leaves), each stamen consisting of a stalk or filament with an anther on the top, one or more lobed, supplied with pores or valves containing minute cells, often yellow, generally in a free state, sometimes in company with others, sometimes stuck together, containing fluid protoplasm, called pollen, - they are parent cells, not grains, as they are often called.

The formation of the free pollen cell - its structure and its behaviour in the protrusion of the pollen tube, and its endless diversity of appearance in the higher plants, easily seen under the microscope - will soon teach the gardener that there is no chance work here, but that all is the work of some master-mind. In the centre of the flower is the pistil, consisting of stigma, style, and ovary, also formed of metamorphosed (pistillar) leaves, or carpellary leaves or carpels, the edges of which have been so folded and tucked inwards as to form the style, of which there are many different forms; and at its summit the stigma, formed of cellular tissue, but without epidermis, whose office is to receive the pollen cell, which, either by falling upon, or by the work of insects, comes in actual contact with the stigma, and is soon followed by the protrusion of the pollen tube (in Orchids this tube may easily be seen and traced to the ovule), which, passing through the stigma and style (often cylindrical), fertilises and energises the ovule in the ovary at the base of the pistil.