x1v CONTENTS 
Organizations of plant breeders. 
Summary . 
CHAPTER XVI 
On Varieties IN PLANTS 
Introductory . : : 
Extent of variety differentiation in Palate : 
The origin of domestic varieties of plants 
Origin of sweet pea varieties . 
Flower color in sweet peas. 
Form and size in sweet peas . 
Habit in sweet peas. : ‘ 
Hybridization and selection in wake oweet pea 
Creation of varieties of the rose 
Origin of varieties in the Boston Fern . 
CHAPTER XVII 
THE ComposiITION or PLant PoPpuLATIONS 
Introductory . : 
Reproduction in planes : 
Plants normally self-fertilized 
Plants normally cross-fertilized 
Discussion : 
Populations of plants morally sel fer alized 
Populations as affected by crossing . 
Summary . 
CHAPTER XVIII 
SELECTION 
Introductory . F ; 
Selection methods in maize Sirecdins : 
Inbreeding in maize. 
The ear-to-row method . é 
The Illinois Station experiments 
The remnant system : ee 
Selection methods in Close pullinarad planis i 
The plant-to-row method . 5 
Ineffectiveness of continued selection ain pure ies 
The practical importance of keeping varieties pure . 
CHAPTER XIX 
HYBRIDIZATION 
Introductory . 
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