CONTENTS 



CHAPTER PACK 



Preface ..... v 



Contents . . . , vii 



List of Plates ix 



List of Drawings in the Text x 



I, The Absorption of Water and Salts . . . . i 

 The Necessity of Water for the Plant, i. The Origin and 

 Nature of Soil, 2. The Root System, 22. The Absorp- 

 tion of Water, 47. The Absorption of Salts from the Soil, 62. 

 Exceptional Means of absorbing Water and Salts, 70. 



n. Assimilation and Transpiration 78 



The Significance of Assimilation and Transpiration, 78. The 

 Leaf, 83. Relation of the Stomata to Gaseous Exchange, 84. 

 Distribution and Dimensions of Stomata, 89. Diffusion 

 through the Stomata, 91. Stomatal Movements and their 

 Mechanism, 102. Gaseous Exchange of Aquatics, iio. 

 Gaseous Exchange of Succulents, 113. Energy Relations 

 of Assimilation, 113. Orientation of the Leaf and Illumina- 

 tion, 115. Mechanism of Leaf Adjustment, 119. Orienta- 

 tion of Strongly Insolated Leaves, 123. Leaf Structure and 

 Assimilation, 126. Chlorophyll and Absorption of Light, 

 128. Chlorophyll in its Relation to Assimilation, 132. 

 External Conditions and Assimilation, 139. Assimilation 

 in Natural Environment, 147. Extent of Transpiration, 159, 

 Water Balance, Wilting and Water Storage, 160. Atmo- 

 spheric Conditions and Transpiration, 163. Stomatal Regu- 

 lation, 166. Regulation by Internal Leaf Changes, 173. 

 Limitation of Transpiration by Form and Position of Stomata 

 and by Cuticle, 175. Hairiness and Transpiration, 179. 

 Effect of Ethereal Oils, 184. Number of Stomata, 185. 

 Reduction of Leaf Surface and Transpiration, 185. Moorland 

 Xerophytes, 190. Leaf Reduction : Transference of Assimi- 

 lating Function, 192. Transpiration of Succulents, 196. 

 Assimilating Roots, 198. The Significance of Xerophytism, 

 199. Promotion of Transpiration, 201. Functions of Tran- 

 spiration, 207. Inter-relation of Transpiration and Assimi- 

 lation, 213. 



III. Special Modes of Nutrition 217 



Parasites, 218. Saprophytes, 240. Mycotrophic Plants, 244. 

 Bacterial Symbiosis, 258. Insectivorous Plants, 267. 



Vll 



3 ^ " 



