80 Principles of Plant Culture. 



locate the point at which growth started in spring (Fig. 

 36). Indeed we can often determine the amount of 

 growth that took place during the preceding season or 

 even farther back. 



118. The Ultimate Length of the Internodes in any plant, 

 or any part of a plant, depends upon the rate of growth — 

 m, rapid growth producing long internodes, and 

 vice versa. In the same species, therefore, the 

 average length of the internodes is much greater 

 in vigorous, young plants than in old ones; in 

 the main, central shoot than in the branches, and 

 when growth is well started in spring than dur- 

 ing its decline in autumn. The diameter of 

 young internodes tliat are not unduly shaded is 

 generally in proportion to their length, hence 

 <^ rapidly-growing shoots are usually thicker thau 

 ' slower-growing ones. We can judge of the com- 

 parative vigor of nursery trees by observing the 

 length and diameter of the internodes. 

 Union of "^- ^*'® Stem Elongates Fastest just behind 

 new and tlie growing point (67), and at least in young 

 plants, just behind the primary or original 

 growing point (56). AVhen we desire to check growth 

 of the stem, therefore, we remove the terminal growing 

 point by pinching (416 a). 



120. Pinching Stimulates Branching because removing 

 the terminal growing point stimulates the development 

 of other growing points farther back (105). 



