CONTENTS 



PAG F, 

 INTRODUCTION . . . '. . . i 



BOOK I 



THE EVOLUTION OF THE PLANT-WORLD 

 CHAP. 



I. The Distribution of Land and Water in the Past . 7 



II. Climate in the Past 10 



III. The Time and Place of the Origin of Plant-life . ' 13 



IV. Floras of the Past 14 



V. The Coming of our Modern Angiosperms . . .20 



BOOK II 



THE FACTORS OF DISTRIBUTION 



I. The Climatic Environment and the Response to it . 27 



II. The Soil 45 



III. Organic Environment . . . . . 55 



IV. Dispersal and Migration 62 



V. Physiographic Factors ...... 70 



VI. Barriers 74 



VII. Insular Floras 78 



VIII. Bridges ..... . .82 



IX. Mountain Floras ....... 86 



X. Water-plants . . 90 



BOOK III 



FLORISTIC REGIONS 



I. The Northern Zone .... -95 



II. The Tropical Zone ... .102 



III. The Southern Zone . .112 



BOOK IV 

 BOTANICAL ECOLOGY OR TOPOGRAPHY . . 122 



BIBLIOGRAPHY . . . 131 



INDEX ......... 133 



Vll 



