THE VEGETATIVE ORGANS OP PLAITTS. 263 



mates, have hranching stems, originating in the following 

 manner : As the principal or main stem elongates, so that 

 the leaves arranged upon it separate from each other, 

 we may find one or more side or axillary buds at the point 

 where the base of the leaf or of the leaf-stalk unites with 

 the stem. From these buds, in case their growth is not 

 checked, side-stems or branches issue, which again sub- 

 divide in the same manner into branchlets. 



In perennial plants, when young, or in their young 

 shoots, it is easy to trace the nodes and internodes, or the 

 points where the leaves are attached and the intervening 

 spaces, even for some time after the leaves, which only 

 endure for one year, are fallen away. The nodes are mani- 

 fest by the enlargement of the stem, or by the scar covered 

 with corky matter, which marks the spot where the leaf- 

 stalk was attached. As the stem grows older these indi- 

 cations of its early development are gradually obliterated. 



In a forest where the trees are thickly crowded, the 

 lower branches die away from want of light ; the scars 

 resulting from their removal are covered with a new 

 growth of wood, so that the trunk finally appears as if it 

 had always been destitute of branches, to a great height. 



When all the buds develop normally and in due propor- 

 tion, the plant, thus regularly built up, has a symmetrical 

 appearance, as frequently happens with many herbs, and 

 also with some of the cone-bearing trees, especially the 

 balsam-fir. 



Latent Buds. — Often, however, many of the buds re- 

 main undeveloped either permanently or for a time. 

 Many of the side-buds of most of our forest and fruit trees 

 fail entirely to grow, while others make no progress until 

 the summer succeeding their first appearance. When the 

 active buds are destroyed, either by frosts or by pinching 

 ofi", other buds that would else remain latent, are pushed 

 into growth. In this way, trees whose young leaves are de- 

 stroyed by spring frosts, cover themselves again after a 



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