CONTENTS 



CHAPTER I 



PAOB 



Introduction .... .... 1 



CHAPTER II 

 The Conditions of Pi.axt Life . ... 17 



CHAPTER III 

 The Simplest Forms of Life 31 



CHAPTER IV 

 Alg^. . . 48 



CHAPTER V 

 Fungi . . . .... 80 



CHAPTER VI 

 Mosses and Liverwort.s (Bryophyta) .... 101 



CHAPTER VII 

 The Ferns (Pteridophyta) ..... 122 



CHAPTER Vni 

 Pteridophyta (Concluded) .... . , 139 



