The increase in the culture of this class of plants throughout Europe and America within the last few years is really astonishing, and the great perfection which is attained in the cultivation of such kinds that used to be considered almost impossible to manage. The high, moist, and almost unbearable temperature which used to be thought indispensable in the successful culture of orchids, has been greatly abandoned, and a more airy and natural temperature adopted and with marked success. The plants are healthier, flower more abundantly, and kept easier free of insects than when the extreme high temperature system was employed. The great rage throughout England, just now, appeal's to be for what are called " cool orchids," which comprise some of the finest treasures in the floral world, such as some of the species of Cattleya, Odontoglossum, Masdevallia, Disa, Barkeria, Ly-caste, and many others which can be grown in any house when a cool, steady, moist temperature can be maintained free from cold draughts of air passing through amongst the plants. The numerous varieties of Odontoglossum Pescatori, O. Alexandrae, and O. Grande, give them an attraction, making them worthy of a house specially devoted to their culture.

The Odontoglossum house being a specialty about a good many places in England and Scotland. Of course it is not to be supposed when a cool temperature is mentioned that a cold temperature is meant, and that a general collection of orchids will, with impunity, bear a low temperature for any lengthened time is erroneous; from such treatment such plants as Phalaenopsis, Saccolabiums, a good many of the Vandas, and other genera from the East Indies may look for a short time in a healthy condition, but spot is eventually sure to make its appearance, and if once this worst of all orchid diseases, gets a commencement in a collection of orchids, it is difficult to stop, and can scarcely be cured. The most devastating case I ever witnessed of this disease was in a valuable collection of orchids in the North of Scotland. The plants had been growing vigorously for several years, when a change of gardener, who was a strong advocate of the cool treatment system, changed the temperature, keeping it too cold for the welfare of the plants, the result being spot of the most malignant kind upon Phalaenopsis, Vandas, AErides and Saccolabiumis, completely destroying this once beautiful collection.

I visited a collection of orchids, a short time ago in this country, composed of East Indian and Mexican orchids, which have been kept for some time back very cool, and although previously in excellent health, I could observe upon some of those which are natives of very warm countries strong indications of spot making its appearance, while such kinds as are natives of Mexico and other parts of Central America, are in excellent condition, fully substantiating what experience has always taught me, that while orchids from the highlands of Central America do best and keep in the healthiest condition when grown in a cool steady temperature, when sufficient air is admitted to prevent a stagnant atmosphere, such plants as are natives of Moulmain, and other parts of Bur-mah, require a much warmer temperature at all seasons, especially when making their growths.

One of the most fatal mistakes in growing cool house orchids, is keeping them too dry at all times, which is just the opposite of what they should be, more especially in this country, where evaporation is so rapid.

Mr. Rand, in his excellent work on Orchid Culture, says: "Orchids must have a house for themselves." This I do not altogether agree with, as the fine specimen plants I saw of some of the most difficult kinds in cultivation at some of the places I visited during my stay in England this winter, which were growing in houses mostly devoted to the culture of other plants, testify that they can be grown, and with success associated with other plants. Where there is a large collection of orchids, or of any particular class of plants, it is unquestionably the better way to devote a place for themselves; but no collection of plants in the country, whether greenhouse or hot-house, can be considered complete without a few orchids in it. Some of the finest orchids we have are of much easier culture than plenty of the hot-house and greenhouse flowering plants.

I have seen some excellent specimens of ornamental-leaved plants and good plants of orchids in fine flower, exhibited at the different horticultural exhibitions in Boston, but very seldom have I seen a good specimen of Stephanotis, Ixora, Franciscea or Dipladenia exhibited. Horticulturists are not needing, therefore, to be deterred from having in their collections a few orchids, because they cannot set aside a house for their particular culture. Bestow the same care upon orchids which other plants require, with which they can be associated, and they will amply repay the trouble.

The following is a list of a few kinds suitable for culture in the greenhouse: Dendiobrium nobile, Cattleya citrina, Cattleya Mossise,

Ccelogyne cristata, Cyprepedium barbatum, Gyprepedium venustum, Cyprepedium insigne,

Lycaste, Skinnerii. Odontoglossum grande. Odontoglossum Alexandras. Phajus grandifolius. Phajus Wallichii. Zypopetalum Mackayai. Zypopetalum Maxilan.