[xix] 



CONTENTS 



PAGES 



AUTHOR'S I'REFACE v-viii 



PREKACE TO THE ENGLISH EDITIOX ix 



A. K. W. SCHIMPER : AN APPRECIATION x-xvii 



FIRST PART. THE FACTORS 



CHAPTER I. WATER 



I. The Vegetative Organs of Terrestrial Plants. i. General Considerations. 

 Hygrophytes ami .\cro|)liytes. IJmbrophoby and ombrupliily. Physical and physiological 

 dryness. Characters of tropophytes. Climatic and edaphic xerophytes, hygrophytes, and 

 tropophytes. ii. XeropJiyles. Factors reducing the absorption of water. Factors favouring 

 transpiration. Xerophilous structure. Protective means against the loss of water. Correlations 

 among xerophytes of different habitats, iii. Hygrophytes. Wiesner's and Lothelier's re-earches. 

 Hygrophilous structure. Removal of superfinous water : dripping points, hydalhodes. iv. 

 Tropophytes. Tropo|ihilons structure. Leaf-fall. 2. Vegetative Organs of Aquatic 

 Plants. Chanije in structure of submerged terrestrial plants. Characteristics of true aquatic 

 plants. 3. Water and Reproduction. Hostile influence of moisture on sexual reproduction. 

 Sexual reproduction in aquatic plants. 4. Water and the Dispersal of Seeds. Adaptations 

 of fiuits and seeds for dispersal by water-currents. Marine drifts. The new flora of 

 Krakatoa ................ 1-34 



CHAPTER II. HEAT 



I. General Considerations. Heat and the structure of plants. Effects of a cold climate 

 on the form and lie of leaves. The three cardinal points. Phaenology. 2. Zero Points of 

 Plant-life. i. Loivcr Zero Points. Power of resisting cold. Death by cold often due to 

 (Irouglit. The coldest points on the earth, ii. Upper Zero Points. Power of resisting heat. 

 Sachs' researche-. Hot sjirings. Highest observed temperatures in soil and air. 3. Cardinal 

 Points ofthe Functions of Plants. The harmonic optimum. The absolute optimum. The 

 oecological optimum. Fluctuations of the harmonic optimum during development. The oeco- 

 logieal optima of a peach-tree. Cardinal points of germination. Germination, growth, assimi- 

 lation, and respiration at low temper.itures. Useful low temperatures. Effects of cold on sexual 

 reproduction. 4. Acclimatization. Transference from a warm to a cold climate and the 

 reverse. Schuebeler's and A. de Candolle's researches. H. Mayr on the acclimatization of 

 f°''«'"fees 35_53 



CHAPTER HI. LIGHT 



I. General Considerations. Importance of light in phyto-geography. 2. Photometric 

 Methods. \\iesner's work. 3. Plant-life in Darkness. 4. Intensity and Quality of 

 Light Effects of light of various intensities on the different functions. Harmfiilness of light 

 of high intensity and the corresponding means of protection. Unequal action of different kinds 



f rays. Absolute and oecological optima of light. 5. Sun and Shade. Full light, light 

 from above, light from the front, liglit from behind, light from below. Direct sunlight and 

 diffuse light. Wiesner's determination ofthe actual photic ration of plants. Unequal demands 

 m.ade on light by sun-plants and shade-plants. Contrivances for concentrating light possessed by 



hade-plants. 6. Day and Night. Phyto-geographical significance of the unequal duration of 



laylight. Bonnier's investigations with continuous illumination .=14-68 



b 2 



