XIV 



TABLE OF CONTENTS. 



CHAPTER XII. 



Laticiferous Tubes. 



Sect. 131. 



PAGK 



CHAPTER XIII. 



Arrangement of the Intercellular Spaces. 



Sect. 132. Spaces containing Air 



„ 133. Intercellular Secretory Reservoirs 



440 

 440 



SECOND SECTION. SECONDARY CHANGES. 



CHAPTER XIV. 



Secondary Growth in Thickness of Normal Dicotyledonous Stems 



and Roots. 



I. Cambivim. Secondary Thickening. 



Sect. 134. Origin of the Cambium in the Stem. Intermediate Bundles . . . 454 



„ 135. Subdivisions of the Secondary Thickening in the Stem .... 458 



„ 136. Cambium and young Secondary Growth 461 



„ 137. General Arrangement of the Secondary Elements as seen in Transverse 



Section ............. 469 



,, 138. Their Longitudinal Course 470 



„ 139. Cambium and Secondary Thickening of Roots 473 



II. The Wood. 



I. Distribution and Form of the. Zones of Secondary Growth. 



5) 

 )) 

 )) 

 )) 



140. 



2. The Tissues of the Secondary Wood 



141. Synopsis 



142. Tracheae ..... 



143. Woody Fibres .... 



144. Cells 



145. Crystal-sacs. Laticiferous Tubes 

 Critical Note .... 



3. Distribution of the Tissues in the Wood. 

 146. General Considerations 





a. Medullary Rays and Medullary Spots. 



147. Medullary Rays ....... 



148. Medullary Spots 



475 



478 

 478 

 481 



483 

 487 

 487 



488 



489 

 492 



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