CONTENTS 



IV. The Absorbing System among the Thallophyta 



PAGE 



259 



GHAPTEE VI. 



THE PHOTOS YNTHETIC SYSTEM. 



I. General Considerations 



II. Photosynthetic Cells -------- 



A. Shape of the Cells. Character of the Cell-walls - 



B. Chloroplasts --------- 



1. Form and Structure of Chloroplasts - - - - 



2. Arrangement of Chloroplasts in the Cell - 



3. Relations between Chlorophyll-content and Photo- 



synthetic Activity ------ 



III. Anatomy of the Photosynthetic System - - - - 



A. The Principle of Maximum Exposure of Surface 



B. The Principle of Expeditious Translocation 



1 . Various Modes of Construction of the Photosynthetic 



System -------- 



2. Experimental Data concerning the Emigration of 



Carbohydrates from the Photosynthetic System - 



IV. Influence of Light upon the Distribution and Organisa- 



tion of the Photosynthetic System ... - 



V. The Photosynthetic System among Bryophy'ta and Algae 

 VI. Ontogeny' of the Photosynthetic System 



261 



263 



263 



264 



264 

 269 



274 

 276 

 276 



280 



281 

 291 



293 



297 

 300 



CHAPTER VII. 

 THE VASCULAR OR CONDUCTING SYSTEM. 



1. General Considerations 302 



11. The Structural Elements of Conducting Tissues - - 306 



A. Conduction of Water and Mineral Salts ... - 306 



1. Histology of the Water-conducting Tubes - 307 



2. The Functions of Vessels and Tracheides - 312 



3. The Special Uses of Vessels and of Tracheides - - 321 



4. Variations in Hie Development of the Water-conduct- 



ing System in Relation to Different Requirements 322 



5. Tyloses - - - - 325 



