A. S. (New-York.) We recommend you to Messrs. Parsons & Co., Flushing, Long. Wand, to complete your list of rare trees. They have paid much attention lately, to importing rare trees for arboretums, and other choice collections.

Arboretum #1

The peculiarities of the climate of England render it singularly favorable for the growth of a largo collection of the trees and shrubs of temperate regions, from almost all parts of the globe; and hence arose the eminent desirableness of attaching to the Royal Gardens such an Arboretum as should be worthy of Great Britain, and serviceable to its extensive possessions and foreign relations. In pursuance of this object, the best suited localities in these grounds have been devoted to a classified collection of hardy trees and shrubs, amounting to about 3500 kinds (including marked varieties), and they are mostly in a thriving condition. Some years must however elapse ere the general effect of the whole can be fully seen, and the groups of different Pines, Oaks, Planes, Beeches, Ashes, Birches, Poplars, Willows, etc, each forming a clump of allied, but distinct kinds, will produce a beautiful variety of foliage in well-disposed masses, enabling also the visitor to compare the character of a vast number of carefully-named trees adapted to the climate, and to judge of their effect in the lawn, the park, or the forest.

The Arboretum #2

This adjoins the flower garden, and is some what larger in extent; not very showy, being composed of an abundance of green grass, and quite a thrifty lot of trees, scattered frequently without order over the enclosure. It is not strictly an arboretum, for it is not complete, although containing a large list of varieties. It is more favorably considered as a pretty pleasure ground. We do not remember seeing in it even the Purple Peach, and very few of the weeping trees. Many of the latest and most novel cut-leaved sorts have found their way thither. It needs modernizing and progressive planting to keep up with the spirit of the age.

In one corner is a perfect wilderness of maples, gingko trees, poplars and spruces. There are excellent specimens of the Variegated Althea, the Juniperus rigida, small specimens, but with deeply pendent habit and feathery sprays, highly ornamental. The Cercis Canadensis, or Judas Tree, furnishes a good specimen, 40 feet in circumference of branches. The Camperdown Elm is a very fine specimen, though not large; low, 20 feet in diameter, though not over eight feet high. There are fine specimens of the Liquid Amber, with denser heads than we have ever seen before. Why is not this more generally grown as a lawn tree? By training the branches low, we believe it would form heads of exceeding symmetry and grace. When the autumn frosts come, it would be the most gloriously brilliant tree of the lawn. In this arboretum are 29 varieties of pines, with specimens of the California Big Tree, Sequoia, the Cedar of Lebanon, and in all a full hundred of conifers.

There are various nurseries connected with the gardens, in one of which there are 20,000 plants growing, which will be set out in adjacent parks. There are often as many as 35 gardeners employed on the grounds, earning an average of $2 per day.

Connected with these grounds is the botanio hall, a red brick building with high steps. It is 35 feet wide, with a depth of 70 feet. Upon the floor is a beautifully tesselated pavement, and overhead a frescoed ceiling of artistic colors. Magnolias, palm trees, oleanders, •morning glories, pines and their cones, lilies, apples, cotton flowers, tobacco plants, with different fruits, flowers and plants of the tropics and temperate zones, are woven into graceful garlands in the ceiling surrounding the skylight. It is hardly possible to tell all the treasures kept within these walls. Specimens of natural history, seeds of all kinds of vegetables and grain, bottled and arranged together, pine cones of all sizes, papyrus, feather flower, silk from worms fed on lettuce and mulberry leaves, the lettuce showing much the best in color, tea from Paraguay, the Sponge plant, fibre of the palm tree, Angora wool, Egyptian wheat, cotton from Greece, Sea Island cotton, and an immense collection of birds and stuffed animals.

It is a round of great practical interest, and instructive to every visitor.

Close at hand is the residence of Mr. Shaw, wherein all are welcome, and here is kept the record of all visitors, many of them famous. Just beyond is the now justly popular Tower Grove Park of 70 acres, a gift from Mr. Shaw to the city, already beautifully planted and kept. On our return from his house we pass the splendid octagon mausoleum, designed for his final resting place, built of hewn stone, with eight arches, hung over with trees which oast a deep shade. We trust it will be long ere it opens to receive him. Close by is another tombstone, raised as a tribute of respect to a gardener, esteemed for his devotion to horticulture, bearing this inscription:

Arboretum #1

Charles S. Sargent, who has charge of the new Arnold Arboretum, in Massachusetts, writes that it is a success as far as the peculiarities of our climate will allow. 137 acres of beautiful, undulating park-like ground, have been laid out, a large amount of money is at hand, to spend for planting; there are already plenty of trees upon the tract, which are native to New England. Our best horticulturists are watching the experiments with interest.