CONTENTS ix 



PAGE 



C. IncompressibUity - - - - - - -107 



1. Resistance to Longitudinal Compression - - 167 



2. Resistance to Radial Pressure - - - - - 168 



IV. Arrangement of Mechanical Tissues - - - - 168 



A. The Structure of Inflexible Organs ----- 169 



1. Cylindrical Organs - - - - - - - 170 



2. Bilateral Organs ... . 178 



3. Mechanical Arrangements for the Prevention of 



Deformation - - - - - - - 181 



4. Mechanical Arrangements in Connection with Inter- 



calary Meristems - - - - - - 182 



B. The Structure of Inextensible Organs - - - 184 



C. The Structure of Incompressible Organs - - - 187 



1. Resistance to Radial Pressure - - - 187 



2. Resistance to Longitudinal Compression - - - 187 



D. Arrangements for Resisting Shearing Stresses - - - 190 



V. The Influence of External Factors upon the Develop- 

 ment of the Mechanical System - - - - 194 



VI. The Mechanical System among the Thallophyta - - 197 



VII. Ontogeny of the Mechanical System - - - 199 



1. Development of Stereome from Procambium - - 199 



2. Development of Stereome from Protoderm - - 202 



3. Development of Stereome from Fundamental Meri- 



stem 204 



VIII. Special Mechanical Devices ... - 205 



CHAPTER V. 

 THE ABSORBING SYSTEM. 



I. General Considerations - 214 



II. The Absorption of Inorganic Compounds - - - - 217 



A. The Absorbing System of Subterranean Roots - - - 217 



B. Rhizoids - - - 226 



C. The Absorbing Tissues of Aerial Roots - - 231 



D. The Water -absorbing Hairs of Foliage-leaves - - - 236 

 III. The Absorption of Organic Food -materials - 243 



A. The Absorbing System of Embryos and Seedlings 2 13 



B. The Absorbing System among Saprophytes, Parasites, and 



Carnivorous Plants - - - - - - - 250 



