The following interesting letter was not written for publication, but has been placed in our hands by the gentleman to whom it was addressed, with permission to make use of it. The writer is a gentleman of taste and intelligence in horticultural matters from Maine, who usually spends his winters in Florida. The Qnince alluded to is undoubtedly the Chinese (Cydonia sinsnsis). It rarely bears fruit in the north.

"Detained here some days for the river to become navigable, I have had an opportunity to look at horticultural matters in this vicinity. Excepting a garden planted about twenty years ago by a wealthy gentleman of taste, and now containing valuable trees, some of which I shall notice, everything in this line is quite recent Mr. Peabody, of Strawberry celebrity, cultivates a place in Alabama, a few miles west of this; but as his plants are not now in bearing (there have been two weeks of freezing nights following the severe drouth of summer and autumn,) I have not been to visit it No doubt I should find much to interest me in the methods and extent of his Strawberry culture, covering I think seventeen acres. A gentleman of wealth formerly living here, (J. G. Winter, Esq.,) with some of the taste of his family on Long Island, (the Win-tcbs and Princes,) about ten years ago planted Peach orchards, Pear, Apple, and other trees, on a well chosen piece of elevated land about five miles from this city. It has passed into the hands of Mr. R. J. Moses, who has made additions and improvements for three years, rendering it highly profitable.

The sales from his fruits and vegetables this year amounted to $6,000 - his choice early Peaches finding a market at Savannah and (by steamer thence) at New York at $15 to $20 per bushel, long before the Jersey orchards send any. He proposes to extend his planting until his trees shall cover 100 acres, embracing 20,000 Peaches, and a good variety of Pears, Apples, Figs, Apricots, Grapes, etc, not omitting the Almond, Olive, and others more rare.

"In the older garden first alluded to, are some finely grown Pear trees of full northern orchard size, (standards,) sound and thrifty, bearing annually abundant crops. Some have been injured by storms, but otherwise I see no evidences of injury or disease, and can not learn that they hare ever suffered from blight Some younger trees, grafted very high so as to leave a long stem exposed to the hot sun of summer, are scalded, showing the necessity of low-working and low-branching in the form of the tree. There are several varieties among the older trees, from which the others have been worked, but the names are unknown to the proprietor, Wm. Brooks, Esq. who has but recently taken an interest in horticulture. He told me that one kind bore a very choice fruit, surpassing all others in excellence of flavor, and bearing over twenty bushels on the full grown tree. I readily recognised it as the Seckel, from its peculiar growth, (the foliage having fallen,) and was glad to see thirty or forty trees of the same just coming into bearing well stocked with fruit-buds. These are ripe for eating in July and sell in market at seventy-five cents per dozen. Another kind, said to weigh 1 lbs. each, and very good, is probably the Duchesse d'Angouleme, selling at twenty-five cents each.

The most of these trees so exceed in luxuriance of growth the familiar appearance of northern trees, that I could name with certainty none but Seckel - fruit and foliage being absent One, a large and later kind, may be Beurre Diel. I have the promise that specimens of each shall be sent north to me next summer to be named and tested with the same varieties northern grown.

"In this garden is an Oleander, very fragrant, grown to be a wide-spreading tree, upon a clean stem or trunk quite mine inches in diameter at the base. A Crape Myrtle of thirteen inches diameter of trunk; Scuppernong Grapes with stem five inches in diameter; a common Black Cherry that has attained a height of thirty feel in three years; well grown Magnolias, (grandiflora) etc.; shew the great fertility of the soil. There was also the most symmetrical and well-developed Torreya taxifulia that I have ever seen. I gathered four of the seeds from the ground and send them in a box with Quince specimens, but fear they will be too dry to germinate. My attention was called particularly to a tree of the Quince family, remarkable for its large fruit It has been named by some one here, a Cydonia sinensis, and is here commonly called a Quincidonia. Ignorant of all botanical nomenclature beyond a few common nursery names, I do not know its variety and am curious to learn what it is, if known much to you, and how it may be propagated other than from seed, which has been uncertain, while cuttings have wholly failed. As the fruit may be rare at the north, Mr. Brooks has given roe two specimens to tend to you.

These 1 have packed in cotton in a cigar box and sent by express to Savannah, to be forwarded from thence, in care of some ship-master, for Boston, with charge to protect from freezing. One specimen of this fruit weighed 3 lbs. In the box is a scion from the bearing tree, and the end of a shoot which grew six feet the past season on a seedling of the same, and some leaves. If they reach you safely, please send the smaller one to my brother. The tree closely resembles the Crape Myrtle, in its trunk, shedding its bark annually - is of upright growth, like a Pear, until spread by the weight of its fruit, and the wood very close and hard. The fruit grows usually on the upper side of the limbs, the stem but a short bunch not parting from the tree. Its leaf-buds open with the first warm weather, (in February,) and it was so late as yesterday that I took the last of this Season's crop from the tree, showing that a very long season is required for the perfect growth and maturity of the fruit I think I have seen in some book a description of this tree - perhaps in Downing's - but describing it as a shrub or bush, similar I suppose to what we call the Pyrus Japonica. This, however, is a tree twenty feet or more in height The fruit has a strong aroma, peculiar, and, to some, not agreeable.

A very rich preserve is made from its pulp or flesh, after extracting its bitter by boiling, and adding a syrup, while the water in which it has been boiled will make a sweet jelly, its bitter properties disappearing in the second process. Columbus, Geo".