Vlll 



CONTENTS 



CHAPTER 

 XXII. 



XXIII. 



XXIV. 



XXV. 



XXVI. 



SECTION II 

 COMMUNAL LIFE OF ORGANISMS 



Reciprocal Relations among Organisms 



Interference by Man 



Symbiosis of Plants with Animals 

 Symbiosis of Plants with one another. Mutual- 

 ism 



Commensalism. Plant-communities 



page 



82 

 82 



83 



84 

 91 



SECTION III 



ADAPTATIONS OF AQUATIC AND TERRESTRIAL PLANTS. 

 OECOLOGICAL CLASSIFICATION 



XXVII. Aquatic and Terrestrial Plants 



XXVIII. Adaptations of Water-plants (Hydrophytes) 



XXIX. Adaptations of Land-plants 



XXX. Regulation of Transpiration in Land-plants 



XXXI. Absorption of Water by Land-plants 



XXXII. Storage of Water by Land-plants. Water - 



reservoirs . 



XXXIII. Other Structural Characters and Growth-forms 



of Land-plants, and especially of Xerophytes 



XXXIV. Oecological Classification 



XXXV. Physiognomy of Vegetation. Formations. Asso- 

 ciations. Varieties of Associations 



96 



97 

 100 



102 



117 



119 



127 

 131 



137 



SECTION IV 

 CLASS I. HYDROPHYTES. FORMATIONS OF AQUATIC PLANTS 



XXXVI. 



XXXVII. 



XXXVIII. 



XXXIX. 



XL. 



XLI. 



Oecological Factors 



Formations of Aquatic Plants . 



Plankton-formation 



Cryoplankton. Vegetation on Ice and Snow 

 Hydrocharid-formation or Pleuston 



149 



154 



155 

 163 



164 



LiTHOPHiLOUS Benthos 167 



XLII. Benthos of Loose Soil 



173 



