CHAPTER IV. 



THE SEEDLIXG AXD YOUNG PLANT (continued}. 



ITS SHOOT-SYSTEM DISTRIBUTION OF THE TISSUES. 



I NOW proceed to describe the chief features of im- 

 portance in the structure of the shoot of the young oak- 

 plant, premising that many of the remarks may here be 

 curtailed in view of the facts already learned in connec- 

 tion with the root. The first object will be to bring out 

 the differences in the shoot as contrasted with the root, 

 and first we may examine the structure by means of 

 transverse sections as before. The shoot consists of all 

 the structures developed from the plumule. 



Such sections show that we have here also various 

 definitely grouped tissues, of which we may conveniently 

 distinguish three systems. A series of vascular bundles 

 grouped in a close ring constitutes one of these systems ; 

 another is represented by a single layer of cells at the 

 periphery of the section, and this is called the epider- 

 mis ; and the remainder of the section composes the 

 third system, often termed the fundamental tissue, and 

 divided arbitrarily into three regions the pith, the cor- 

 tex, and the primary medullary rays (Fig. 9). The 



