Hybridizing, aided by cultivation, gives birth to these objects of the gardener's care generally designated double flowers, which are such beauteous ornaments of our borders and parterres. To the uninitiated it seems incredible that the double moss rose should be a legitimate descendant from the briar; neither do the flowers of the Fair Maid of France appear less impossible derivatives from those of the Ranunculus platanifolius; nor bachelors' buttons from the common buttercup; yet so they are. Double flowers, as they are popularly called, are more correctly discriminated as the full flower, the multiplicate flower, and the proliferous flower.

The full flower is a flower with its petals augmented in number by the total transformation into them of its stamens and its pistils. One-petalled flowers rarely undergo this metamorphosis, but it is very common in those having many petals, as in the carnation, ranunculus, rose, and poppy. But this is not the only mode in which a flower becomes full, for in the columbine (Aqui-legia) it is effected in three different ways, viz., by the multiplication of 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, whilst the usual petals remain.

Radiated flowers, such as the sunflower, dahlia, anthemis, and others, become full by the multiplication of the florets of their rays to the exclusion of the florets of their disk. On the contrary, .various species of the daisy, ma-tricaria, etc, become full by the mul-plication of the florets of the disk.

The multiplicate flower has its petals increased by the conversion of a portion of its stamens, or of its calyx, in those forms. It occurs most frequently in polypetalous flowers. Linnaeus gives the only instances I know of the conversion of the calyx into petals, and these are to be observed in the pink Dianthus caryophyllus), and a few of the Alpine grasses.

A proliferous flower has another flower or a shoot produced from it, as in the variety of the daisy popularly known as the hen-and-chickens. It occurs also more rarely in the ranunculus, pink, marigold, and hawkweed. A leafy shoot often appears in the bosom of the double-blossomed cherry, anemone, and rose.

A due supply of moisture, but rather less than the plant most delights in, when the production of seed is the desired object, a superabundant supply of decomposing organic matter to its roots, and an exposure to the greatest possible degree of sun-light, are the means successfully employed to promote that excessive development of the petals which characterize double flowers.

By these means a greater quantity of sap is supplied to the flower than the natural extent of the petal can elaborate; and following the laws of nature specified elsewhere, those parts required for the extra elaboration, are developed at the expense of those not demanded for the purpose.

The chief office of the petals is this preparation of nourishment for the stamens, and for the most part they fade together, usually enduring until impregnation has been effected, or has altogether failed. In double flowers, too, as was observed by the late Sir J. E. Smith, the corolla is much more durable than in single ones of the same species, as anemones and poppies, because as he conceived, in such double flowers the natural function not being performed, the vital principle of their corolla is not so soon exhausted. Advantage may be taken of this to prolong the duration of flowers by cutting away the pistils or stamens, whichever are least conspicuous, with a sharp pair of pointed scissors.

Although an abundant supply of nourishment is absolutely necessary for the production of double flowers, it is quite as certain that such supply will not of a certainty cause their appearance; there must be some tendency in the parent thus to sport, otherwise the superfluity of food will not have the desired influence. That abundance of nourishment is necessary, appears from the fact that if the double daisy or the double narcissus be grown in a poor soil, they speedily produce none but single flowers; yet if they again be restored to a rich soil, they may with care be made to produce an unnatural profusion of petals. Mr. D. Beaton's estimate of a double flower is original. He says that cultivation having enlarged all the parts of a plant, the constitutional vigour thus obtained is transferred to the next generation, and to some of the seedlings, in a measure even greater than that possessed by the parent. Extraordinary supplies of nourishment under favourable circumstances, invigorate still further the improved race, and so on through many generations.

During this time cultivation produces the very opposite of double flowers, and Mr. Beaton thinks it would continue to do so, if it were possible to keep up every member of each generation to the same degree of health and vigour; but accidents and diseases overtake some of the plants, and double flowers are the produce from the decre-pits. Cultivation, according to this idea, is only indirectly the cause of double flowers, and these a retrograde step from a high state of development.

Whether my own opinion or Mr. Beaton's be correct, it is quite certain that in practice the plants from which double-flowered varieties are sought, must be kept in the highest state of development by supplying them abundantly with all the assistance to vigorous growth; and when the seed vessels are formed, they should be reduced in number in order to make the seed in those remaining as large and perfect as possible. In the course of a few generations, seedlings appear, having flowers with an excess of petals, and seeds being obtained from these, or from other flowers impregnated by their stamens, and the same high cultivation continued, the excess of petals increases and becomes a permanent habit.