Flower, or Flos, the most beautiful part of plants and trees, which contains the organs of fruc-tification. - See Botany, vol, i. p. 316.

From their frequent utility as medicinal drugs, as well as their external beauty, the preservation of flowers becomes an object of some importance. For this purpose, various methods have been devised, from which we select the following, originally suggested by Sir John Hill : Let a sufficient quantity of fine sand be washed, so as completely to separate all extraneous matter. It is next to be dried, and sifted in order to cleanse it from the gross impurities that would not rise in washing. The flower or plant intended to be preserved, should then be gathered with a convenient portion of the stalk, and deposited in an earthen vessel adapted to its size. A small quantity of the sand, prepared as above directed, is next to be heated, and laid on the bottom of the vessel, so as to cover it equally, and the plant or flower placed on such sand, so as to touch no part of the vessel. More sand is then to be sifted over, that the leaves may gradually expand, without receiving any injury, till the plant or {lower is covered to the depth of two inches. The vessel is now to be placed in a stove, or hot-house, heated by gradations to the 50th degree of Reaumur, or about 144° of Fahrenheit), where it should stand for one, two, or more days, in proportion to the thickness or succulence of such plant, or flower. At the end of that time, the sand may be gently 6haken off on a sheet of paper, and the plant carefully taken out, when it will be found in all its beauty ; its shape being as, elegant, and its colours as vivid, as when it was growing in a natural state.

There are some flowers, especially tulips, which require certain little operations, in order to preserve the adherence of their petals. With respect to these, it will be necessary to cut the triangular fruit that rises in the middle of the flower, previously to covering it with sand ; for the petal will then remain more firmly attached to the stalk.

This method may be applied to such plants and flowers as are employed in medicine : for, though it be not always necessary to preserve their original colour and form, yet the less change they undergo, the better will they retain their natural properties. Farther, the preservation of beautiful leaves and flowers in their original shape and colour, by placing them, in such a situation that they may suffer no subsequent alteration, except that from length of time or accident, is surely an object that merits the attention of every lover of Nature. - See Herbal.

Beside this mode of preserving flowers, they may be prepared so as to retain their beauty during the winter, and even to blow at any period required. In order to succeed in in this attempt, the most perfect buds of the flowers, should be selected at the time when they are about to open. These should be cut off with a pair of scissars, leaving to each a piece of the stem about three inches in length ; the end of which is immediately to be covered with Spanish wax. As soon as the buds are somewhat shrunk and wrinkled, they are to be folded up, separately, in a piece of clean dry paper, and deposited in a dry box or drawer, where they will keep without decaying.— In the winter, or whenever the flowers are required to blow, the wax is to be cut off the buds, and these should in the evening be im-mersed into water, in which a little nitre, or common salt, has been dissolved : if exposed to the rays of the sun, on the succeeding day, they will expand with all their original fragrance and beauty.

There are a few general remarks made by eminent botanists, on the growth, enlargement, colours, and duplication of flowers; the sub-stance of which we shall communicate under the following heads :

1. It is an established fact, that flowers as well as fruits grow larger in the shade, and ripen and decay soonest, when exposed to the sun. Hence, likewise, the foliage or buds of plants requires more moisture for its vigorous growth than their flowers, or organs of fructification. Farther, observes Dr. Darwin, the frequent rains of our climate, are apt not only to wash off the farina from the bursting anthers, and thus to prevent the impregnation of the pistil, but also to delay the ripening of the fruit or seeds, from the want of a due evaporation of their perspirable matter, as well as from the deficiency of solar light in cloudy seasons. In another place of his admirable "Phytologia," this philosopher remarks that, as a superfluous supply of water is more friendly to the growth of leaf-buds, than to the generation of flower-buds, the production of seeds may be forwarded by supplying their roots with less water than usual. But when the blossoms appear, an addition of water promotes their growth, by affording nourishment, which should again be lessened, when the fruit has acquired its full size, both to promote its maturity and improve its flavour; as the saccharine matter and essential oil will thus be in a less diluted state. - Although the fruit may become sweeter and larger, when the green as well as the floral leaves continue on the tree, yet the corols with the stamens, stigmas, and nectaries (the succeeding fruit not considered) surfer, in the opinion of Dr. Darwin, no injury when both kinds of leaves are removed, as by the depredations of insects. Nay, some florists assert, that the flowers thus become stronger, producing no bulbs, as is the case with tulips and hyacinths.

2. The variegated colours of the petals of flowers are so beautiful, and afford such delight to the eye of the contemplative naturalist, as to deserve some investigation. It is probable that varieties in the colours of single flowers raised from seeds, maybe generally obtained by sowing those which already possess different shades, contiguous to others of the same species; or, by bending the flowers of one colour and shaking the anther-dust over those of another. Thus Dr. Dar-win supposes the beds pf the corn blue-bottle, centaurea cyanus, ac-quire those beautiful shades of blue, purple, and white. As some animals change their natural colours, when transplanted in different situations of soil, a similar effect may be produced by sowing flowers in factitious composts, which considerably differ from each other with respect to vegetable nutriment, and perhaps also in their colour. Experiments on this subject, as well as on the variegation of the leaves of shrubs and trees, are however wanting to confirm this conjecture; though the latter probably originates from soil or situation, and may be communicated by ingrafting.— Theoriginof newcolours in flowers, and of variegated foliage, is imagin-ed to arise from the want of nourishment of the soil on which they grow, compared to that assigned to them by Nature ; or from a defect of moisture and of heat; a supposition countenanced by the dwarfish size of such plants, in general, and especially by the reduced stature of tulips, when their petals ac-quire various colours.

The immediate cause of the various colours presented by some flowers, such as poppies, has not hitherto been distinctly ascertained; but Dr. Darwin conjectures that, as they are not variable by the obliquity with which they are seen, like those of mother-pearl, card-fish, etc. they do not depend on the thinness of their pellicle, and may, therefore, arise from the greater facility which some parts of vegetables, more than others, possess in parting with their oxygen (which see) when exposed to the sun's light; for all flowers are more or less blanched before they first open.

3. The origin of double flowers is believed to result from the luxuriant growth of the plant, in consequence of excessive nourishment, moisture, and warmth : they arise from the increase of some parts of the flower, and the consequent exclusion of others, As they present a greater blaze of colour in a small space, and continue in bloom for some weeks longer than single flowers, the method of producing them from seeds is a matter of importance. Botanists very properly term such rnuitiplied flowers vegetable monsters, because they possess no stamens or pistils, and therefore can produce no seeds. - Nevertheless, they are frequently raised immediately from seeds; because flowers cultivated with more manure, moisture, and warmth than is congenial to them, not only grow larger and more vigorously, but likewise shew a tendency to become double, by having one or two supernumerary pestals in each flower, such as the stock July flower, cheiranthus, and anemone. It is stil lmore remarkable, that this duplicative is communicated to those individual blossoms: hence florists tie a thread round such flowers, to mark them, and to colled their seeds separately, from which double or full flowers are said to be uniformly produced, if they be cultivated with additional manure, moisture, and warmth, as has been already observed. - There subsists a curious analogy, concludes Dr. Dak-win, between these vegetable monsters and those of the animal world; for a duplicature of limbs frequently attends the latter, as chickens and turkeys with four legs and four wings, and calves with two heads. In mules, also, the most important organs become deficient, so that they cannot propagate their species; exactly analogous to these full flowers which, from the same cause, produce no seed. With respect to botanic systems, it may be observed from these vegetables of exuberant growth, that the stamens and pistils are less liable to change than the corols and nectaries ; consequently, that they are more proper parts for arranging plants into classes; and that on this idea Linnaeus constructed his unrivalled system. Lastly, the calyx, or perianth, being seldom found in a double or multiplied state, is the next part of a flower that is liable to the least changes; and may, therefore, on accurate inspection, fcerve to detect the genera of many duoble flowers.

With respect to the colours which may be extracted from flowers, we refer the reader to the article Colouring Matter, p. 38, and to the different flowers as they occur in their alphabetical order.