CONTENTS 



INTRODUCTION 



CHAPTER 



I. FLORISTIC AND OECOLOGICAL PLANT-GEOGRAPHY 



II. GROWTH-FORMS 



III. PLANT-COMMUNITIES 



IV. PLAN OF THIS BOOK 



PAGE 



i 



2 



12 

 14 



SECTION I 

 OECOLOGICAL FACTORS AND THEIR ACTION 



V. LIGHT 16 



VI. HEAT 22 



VII. ATMOSPHERIC HUMIDITY AND PRECIPITATIONS . . 28 



VIII. MOVEMENTS OF THE AIR . .36 



IX. NATURE OF THE NUTRIENT SUBSTRATUM ... 40 



X. STRUCTURE OF THE SOIL 40 



XI. AIR IN THE SOIL 43 



XII. WATER IN THE SOIL 44 



XIII. TEMPERATURE OF SOIL 50 



XIV. DEPTH OF THE SOIL. THE UPPER LAYERS OF THE SOIL 



AND THE SUBSOIL 54 



XV. NUTRIMENT IN SOIL . . . .. . . -55 



XVI. KINDS OF SOIL 59 



XVII. ARE THE CHEMICAL OR THE PHYSICAL CHARACTERS OF 



SOIL THE MORE IMPORTANT? 65 



XVIII. THE EFFECT OF A NON-LIVING COVERING OVER VEGE- 

 TATION 72 



XIX. EFFECT OF A LIVING VEGETABLE COVERING ON SOIL . . 75 



XX. THE ACTIVITY OF ANIMALS AND PLANTS IN SOIL . . 77 



XXI. EXPOSURE. OROGRAPHIC AND OTHER FACTORS 80 



