NOTE.
There are a few trees and shrubs, of which the alder and buckthorn are examples, that so seldom show any kind of a tint that I have not included them in my list; and there are several species of oak that display such a motley combination of green and rust, with faint shades of purple and yellow, that it is impossible to classify them. In my list I have only named the genera, except when the species are distinguished by important differences. The brown hues of the oak and the beech are the tints only of their dead leaves or dead parts of leaves; but pure browns are sometimes seen in the living leaf of the snowy mespilus, the pear-tree, and the smoke-tree; in others they occur so seldom that they may be classed as accidental hues. I ought to add that only a small part of what may be said of the tints of trees is unqualifiedly correct. They are greatly modified by circumstances which cannot always be understood. I have seen maples that always remained green, apple-trees dressed in scarlet and yellow, and lilacs in a deep violet; but I have never seen a purple, crimson, or scarlet leaf on any of the trees of Division I. of the Synopsis.