CONTENTS 



CHAP. 



XV. LAND FORMS OF WATER PLANTS, AND THE EFFECT 



OF WATER UPON LAND PLANTS . 

 XVI. THE ROOTS OF WATER PLANTS 

 XVII. THE VEGETATIVE REPRODUCTION AND WINTERING 

 OF WATER PLANTS ..... 

 XVIII. THE FLOWERS OF WATER PLANTS AND THEIR RELA- 

 TION TO THE ENVIRONMENT 



XIX. THE FRUITS, SEEDS AND SEEDLINGS OF WATER 

 PLANTS . 



195 



204 



210 

 227 

 239 



PART III 

 THE PHYSIOLOGICAL CONDITIONS OF PLANT LIFE 



IN WATER 

 XX. GASEOUS EXCHANGE IN WATER PLANTS 



XXI. ABSORPTION OF WATER AND TRANSPIRATION 



CURRENT IN HYDROPHYTES .... 



XXII. THE INFLUENCE OF CERTAIN PHYSICAL FACTORS IN 



THE LIFE OF WATER PLANTS 



XXIII. THE ECOLOGY OF WATER PLANTS . . 



PART IV 



THE STUDY OF WATER PLANTS FROM THE PHYLOGENETIC 

 AND EVOLUTIONARY STANDPOINTS 



XXIV. THE DISPERSAL AND GEOGRAPHICAL DISTRIBUTION 



OF WATER PLANTS ..... 



XXV. THE AFFINITIES OF WATER PLANTS AND THEIR 

 SYSTEMATIC DISTRIBUTION AMONG THE ANGIO- 

 SPERMS ....... 



(i) The Affinities of Certain Aquatic Angio- 

 sperms ..... 



(ii) Theoretical Considerations . 



XXVI. THE THEORY OF THE AQUATIC ORIGIN OF MONO- 

 COTYLEDONS 



XXVII. WATER PLANTS AND THE THEORY OF NATURAL 

 SELECTION, WITH SPECIAL REFERENCE TO THE 



PODOSTEMACEAE . . . . 



XXVIII. WATER PLANTS AND THE 'LAW OF Loss' IN 

 EVOLUTION 



253 

 260 



273 

 285 



295 



308 



308 

 317 



3" 



327 



BIBLIOGRAPHY . 

 INDEX TO BIBLIOGRAPHY 

 INDEX . 



336 

 349 



422 



