also of being less adapted to England than to the United States. Besides, why is it that evergreens thrive better, and are more hardy, in a cultivated state in Europe, and deciduous trees in this country? We know answers can be given by experienced observers to all these questions, that are more or less comprehensive, but we believe also that, when such answers come to be closely scanned, it will be found that they do not entirely meet the case. How is it, otherwise, that the same peculiarities in a minor degree are evident in the behavior of trees growing within a few miles of each other? One might understand why the same plants act differently farther inland, but here in the neighborhood of the coast it naturally strikes us as curious that on the Hudson River some plants are hardier than on Long Island.
There are more inexplicable facts than these. Mr. Hunnewell can grow plants on his lawn that will hardly live through some winters, even under the most favorable conditions, on any other spot about Boston.
Nor is this the strangest feature to be noticed in the behavior of plants under apparently like influences of soil and climate. Plants a few feet from each other, of the same species, will suffer in very different degrees during many winters. Rhododendrons are a notable instance of this. It is not simply that Rhododendron ponticum and its hybrids are not as hardy as Rhododendron Catawbiense, nor that the more of the Catawbiense strain there is in a Ponticum hybrid, the hardier it is, but it is that sometimes a Ponticum hybrid, usually entirely unreliable, will pass the winter unscathed, when nearly the hardiest pure Catawbiense of the plantation will be killed. But our expert says, "One did not ripen its wood as well as the other." Yes, but is it not also strange that sometimes the one which finally died was the one that had ripened its wood most thoroughly?
A few striking examples like these should be sufficient to illustrate the great difficulty that must always attend the determination of the relative hardiness of plants. Many more instances of the same character might be readily selected, but it is not necessary. We have simply endeavored to give sufficient data to warrant the general statement that the varying and complex conditions of the environment of any given plant are difficult to understand or explain on the basis of experience of another environment which, to a superficial observer, may seem to be identical with the first. Our intention is not to insist on any explanation of the facts adduced in regard to the relative hardiness of plants, but only to show distinctly the difficulties that must attend such explanations, and to point out that experience is now being purchased too dearly, and that it is, moreover, not of a sufficiently varied character. Hundreds and thousands of plants are killed every year under very similar circumstances, and it seems evident that human intelligence should be sufficient to compass some method of reducing this loss to a minimum.
