The great event in our floriculture world just now, is the blooming of the Victoria - it queen of water lilies - at the country residence of the President of the Pennsylvania, rtcultural Society. Mr. Cope's seal and spirit in the introduction and cultivation of noble plant, have been most satisfactorily rewarded by a larger growth, both of flower i leaf, than the most skilful culture in Europe has yet attained. We give his letter, I the interesting account of Mr. Ellis, below. Ed.

A. J. Downing, Esq - Dear Sir: I am sorry that you were not here to witness the element which prevailed on the 21st ult., when the Victoria bloomed for the first time in a country, and when my grounds seemed to be in complete possession of the public, ice that event we have bad a weekly contribution of a flower, the fourth one maturing >l evening. The interest felt by the public appears not only unabated, but on the in rase, so that every show day We have crowds of visitors from all parts of the country. I hope before long to send you the drawing of my Victoria house, which you request, the mean time I send you a report from my gardener, which will be interesting to those to wish to look into the detail of the culture and treatment of the plant. If you deem y portion of it worthy of insertion in the Horticulturist, you can make use of it. The committee on plants and flowers of the Horticultural Society, were present on the ond flower blooming. They measured the petals, which they found seven inches in gth, and the crown or disk of the flower throe inches, thus making the diameter of the tola seventeen inches. This is three inches larger than any flower produced in England. ie leaves are also six inches larger than any grown there.

The natural conditions of the int in our country are undoubtedly, more favorable than they can possibly be in Eng-land. There the wa at 85° generally, and the atmosphere at 75°; here it is just the rerse, which is un dly more like its native country. I am satisfied that we have hit upon the right method of cultivating the plant; and that both flowers and leaves are equal to any found either in a native or foreign state, in any part of the world. Although all this has been accomplished at a great expense of money and personal exertion, I do not regret what I have done. I think I never have been so richly repaid in a similar effort. Even Mr. Longworth, who regards so much of what is new in his favorite path, as humbug, says, in a letter which I received from him to day, that "there is but one plant in the world - the Victoria." He adds, however, that he will present me with a fresh-milk cow, if he fails to grow the lily without heat. By this he means that he can grow it in his pond. Our plant is also grown without fire heat. We have had no fire since the 21st June. The plant in the kitchen garden, which has had fire heat at no time, is very beautiful, and would bloom, I think, if it had been planted a month earlier. As it is, I am not without hope that it will yet give us a flower.

The leaves are within three inches as large as the largest leaf spoken of by Bridges. Next season, if I live, I will show you a flower on the same spot, since you invite the effort.

*Gray's Botanical Text Book.

The flower last evening was more gorgeous than any of its predecessors. As its conversion was going on, in its second stage, it seemed that the pink or red hue greatly preponderated over the white. I cut the flower, placed it on a thin circular board, a foot in diameter, which it completely covered, and sent it to a wedding party. Iam in hopes that one of the buds, now visible, will bloom in season for our annual exhibition, which is to be held next week. I shall send two of the leaves - one of them to be placed under side up, so that the beauty of its architectural structure can be seen.

The Victoria is one of the few things that has not been exaggerated; nor is it possible to exaggerate it. It is truly a wonderful plant. Yours very truly, C. Cope.

Springbroak, near Philadelphia, Sept. 10,1851.

A. J. Downing, Esq - Sir: As the experiment of cultivating the Victoria Regit at this place has resulted successfully, I propose giving a brief history of the attempt, not doubting that it will prove interesting to the numerous readers of the Horticulturist.

On the 21st day of March last, a letter containing twelve seeds of the Victoria Regia was received by Mr. Cope, from Sir Wm. J. Hooker, Director of the Royal Gardens at Kew. Four of these were planted in small seed pans, in loam and sand, and placed in a tank of water in the forcing house. This tank, which was five feet by six in diameter, was heated to the temperature of 85° to 95°, by a circulation of hot-water, produced by a copper box being placed upon the furnace, and an inch lead pipe, passing from it twice round the inside of the tank. A coil of half inch pipe, of about fifty feet in length, was also placed over the furnace, in order that the water might be tempered, which was destined to supply the tank. From this pipe the water dropped on a small tin wheel, which agitated the water in the tank, and dissipated the vegetable mucus or slimy matter which accumulated around the borders of it, and sometimes upon the edge of the leaves of the Victoria, after it commenced growing.

Three of the seeds germinated as follows: The first on the 10th of April; the second on the 14th of April, and the third on the 22d of May. The fourth seed failed to grow. The first growth of the lily was in form of a spear, not unlike a young shoot of grass, and attained in length about an inch and a half. On the 17th a second leaf appeared, of a form similar to that of the Calla ethiopica, being long and tapering, from a broad blade.

On the 21st a third leaf appeared of like form.

25th, the fourth

This leaf is six inches larger than any produced in England, of which we have any account.