CONTENTS 

 PART I 



WATER PLANTS AS A BIOLOGICAL GROUP, WITH A CON- 

 SIDERATION OF CERTAIN TYPICAL LIFE-HISTORIES 



CHAP. PAGE 



I. WATER PLANTS AS A BIOLOGICAL GROUP ... 3 



(i) Introduction ...... 3 



(ii) Biological Classification of Hydrophytes . . 5 



II. THE LIFE-HISTORY OF THE ALISMACEAE ... 9 



III. THE LIFE-HISTORY OF THE NYMPHAEACEAE AND OF 



LlMNANTHEMUM ...... 24 



IV. THE LIFE-HISTORY OF HYDROCHARIS^ STRA TIOTES, AND 



OTHER FRESH-WATER HYDROCHARITACEAE . . 42 

 V. THE LIFE-HISTORY OF THE POTAMOGETONACEAE OF 



FRESH WATERS ...... 58 



VI. THE LIFE-HISTORY OF THE LEMNACEAE AND OF PISTIA 73 



VII. THE LIFE-HISTORY OF CERATOPHYLLUM ... 84 

 VIII. THE LIFE-HISTORY OF THE AQUATIC UTRICULARIAS AND 



OF ALDROVANDIA . . . . . . 91 



IX. THE LIFE-HISTORY OF THE TRISTICHACEAE AND 



PODOSTEMACEAE . . . . . .112 



X. THE LIFE-HISTORY OF THE MARINE ANGIOSPERMS . 123 



PART II 



THE VEGETATIVE AND REPRODUCTIVE ORGANS OF 

 WATER PLANTS, CONSIDERED GENERALLY 



XL LEAF TYPES AND HETEROPHYLLY IN AQUATICS . . 139 



(i) Types of Leaf in Water Plants . . 1 39 

 (ii) The Facts of Heterophylly under Natural 



Conditions . . . . . .143 



(iii) The Interpretation of Heterophylly . . 155 



XII. THE ANATOMY OF SUBMERGED LEAVES . . .163 



XIII. THE MORPHOLOGY AND VASCULAR ANATOMY OF 



AQUATIC STEMS . . . . . .172 



XIV. THE AERATING SYSTEM IN THE TISSUES OF HYDRO- 



PHYTES . ..... 183 



