TABLE OF CONTENTS IX 



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SECOxVD PART 

 THE STRUCTURE AND LIFE OF PLANTS 



Division L — The Minute Structure and Vital Pages. 



Processes of Plants . . . . . . 198 



1,— The Single Cell . 198 



2. — The Organic Structure 200 



Division IL — The Structure and Vital Processes 



OF THE Parts of Plants . ... . 20 1 



l.— The Leaf 201 



A. The Outer Structure 201 



B. The Work done by the Leaf 208 



1. Transpiration or Evaporation of Water 208 



2. Assimilation of Food 213 



3. Respiration 219 



2. — The Boot 222 



A. The Work done by the Root and its Main Types 222 



B. The Work of the Root and its Detailed Structure 224 



1. Roots as a Means of keeping the upper Structure in 



Position 224 



2. Roots as a Means of Absorption 226 



3.— The Stem 232 



A. Stems as Means to spread out the Leaves and 



Flowers to the Air and the Sun 232 



1. Growth and Description of Stems . 'w« .... 232 



2. Buds : . . . . 233 



3. Direction of Growtli influenced by Gravity and Light . 234 



4. Habits of Stems 234 



5. Strength of Stems 236 



6. Various Types of Stems 239 



7. Modes of Branching 240 



8. Metamorphosed Stems 242 



B. Stems as Channels for the Ascending and the 



Descending Sap 244 



1. General Structure and Leading Tissues of Stems . . , 244 



