Page:Popular Science Monthly Volume 50.djvu/336

320. This difficulty might only be overcome at some cost by a system of tanks for the storage of rain water, which would furnish exactly the natural conditions for a large number of species.

It is somewhat surprising to learn that in this area of about two thousand square feet more than twelve hundred species are successfully cultivated, almost all of which are perennials. In some places three or even four kinds are grown on a square foot of actual surface—a striking example of a form of intensive cultivation. It must not be supposed, however, that none but Alpine species are grown. A glance at the labels will show



that many are at home far southward in the temperate zone. It is interesting to note that all of the North American species of Cypripedium are grown here successfully. As a matter of fact the alpinum offers a wider range of conditions than any other method of cultivation, and in some form similar to that described might offer suitable conditions of growth for species fairly representative of the flora of a region extending across twenty degrees of latitude.

The glass houses are of the usual form, and include a palm house two hundred feet in length, to which are attached workrooms and the herbarium building. The immediate supervision of the cultural department of the garden is in the hands of the head gardener, who is provided with a commodious dwelling and office building near the arboretum. He has under his direction a