CHAPTER I. 



THE SHOOT-SYSTEM. 



Root-system and shoot-system compared and contrasted Defini- 

 tions Segmentation of shoot nodes and internodes stem, 

 branch, twigs, leaves and other organs The embryo plant 

 its discernible parts cotyledons, plumule, &c. The plumule 

 the primary bud. 



IT is, of course, merely stating the obvious to say that 

 all our ordinary trees and shrubs consist of two principal 

 parts, the stem-parts rising into the air and light and the 

 root-parts descending into the dark soil : nevertheless, it 

 adds to the definiteness and accuracy of our conceptions if 

 we not only emphasize this statement, but also examine 

 it somewhat more closely. It must be noted that we 

 are here speaking of our ordinary common types of trees 

 and shrubs, and with that qualification we may agree to 

 term the underground portions, as a whole, the Root- 

 system, while the parts above-ground, no matter how 

 complex they may eventually become, as stems, branches, 

 leaves, flowers and fruit, &c., appear in succession, may be 

 designated by the comprehensive term Shoot-system. 



But experience soon shows that cases occur where root- 

 system and shoot-system, though sharply marked off one 

 from the other, are not sufficiently defined by the above 



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