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acids within the leaf. These acids are present constantly in theirrespective types of plants. It is a peculiar fact that in some trees autumn colouration is muchmore vivid than in other trees, because of the presence of certain acidsthe chemical reaction of which produces these vivid colours. Theautumn colouration of foliage ranges from the dull browns through theyellows and orange to the brilliant red and scarlet. Some of ourtrees and shrubs such as the red maple, Judas tree, sourwood, sumac,and sassafras, develop their autumn colours during the early partof the fall. In these trees growth stops early in the season andthe wood matures more quickly. There is one group of plantssuch as the Virginia creeper, Thunberg's barberry, red oak, high-bush cranberry, and arrow-wood, in which the autumn colourationis produced shortly after the early trees have shown their autumncolours. The American beech, golden bell, scarlet oak, and burningbush, and some others mature and ripen last of all and are includedin the group with late autumn colouration. With the great oppor-tunity for selection of trees and shrubs from these three well-definedgroups a succession, if it may be so termed, of autumn colourationmay be obtained, which will supplement and add interest to the fruit-ing effects produced by a well-selected group of plants valuable for thecharacteristics of their fruit. |
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