TABLE OF CONTENTS 



CHAPTER T 



PAGES 



THE FACT AND PHILOSOPHY OF VARIATION . . . 1-13 



The fact of individuality, 2 variation and adapta- 

 tion, 7 species-formation, 8 conception of unit char- 

 acters, 9 differences between plants and animals with 

 regard to general association of parts and their methods 

 of reproduction, 10 bud-variation and bud-varieties, 11. 



CHAPTER II 



THE CAUSES OF INDIVIDUAL DIFFERENCES .... 13-33 



Fortuitous variation, 14 action of natural selection 

 on variation, 14 sex as a factor in the variation of 

 plants, 15 physical environment and variation, 16 

 do external influences produce permanent effects in 

 plants, 17 natal and post-natal variations, 18 con- 

 ception of biotypes, 19 variation in food supply, 20 

 variation in climate, 22 food supply in different 

 branches, 23 what cultivation is, 24 variation in cli- 

 mate, 25 man's control over climate as a means of 

 making plants vary, 27 change of seed, 28 bud- 

 variation, 29 struggle for life a cause of variation, 30. 



CHAPTER III 



THE CHOICE AND FIXATION OF VARIATIONS . . . 34-40 



What is a variety, 35 adaptation in nature, 37 

 artificial selection, 37 bud selection, 39 variation 

 and selection not entirely within man's control, 39. 

 ix 



