Vlll 



CHAPTER 



VI. 



VII. 



VIII. 



CONTENTS 



Past ages and their plant life .... 

 Further consideration ...... 



FOUNDATIONS OF MODERN 

 DISTRIBUTIONS 



Some effects of relatively recent climatic changes . 

 Pleistocene persistence versus subsequent immigration 

 Continental drift, shifting poles, land-bridges, etc. . 

 Postglacial changes ...... 



The genetical heritage ...... 



Polyploids and their areas ..... 



Further consideration ...... 



TYPES AND AREAS OF NATURAL 

 DISTRIBUTIONS 



* Continuous ' intercontinental ranges 

 Discontinuous ranges .... 



Relic areas ...... 



Vicarious areas ..... 



Endemic areas ..... 



Polytopy and the incidence of areas 

 Intraneous, extraneous, and other elements 

 Major regions ..... 



Further consideration .... 



MODIFICATION AND DISTRIBUTIONS OF 

 CROPS (AND WEEDS) . 



Effects of cultivation .... 



Naturalization and acclimatization . 



Some herbaceous crops and their areas 



Forestry and other woody ' crops ' 



Significance and distribution of weeds and plant d 



Further consideration .... 



IX. VITAL IMPORTANCE TO MANKIND 



Foods ..... 



Beverages and flavours 

 Medicinals and drugs . 

 Fatty oils and waxes . 

 Smoking and chewing materials . 

 Structural and sheltering materials 

 Industrial uses and extractives 

 Clothing materials and other fibres 

 Fuels (including fossil, etc.). 

 Latexes and exudates . 

 Tanning and dyeing materials 

 Essential oils and scents (perfumes) 

 Insecticides and herbicides . 

 Environmental and ecological 

 Aesthetic and ornamental 

 Microorganisms and miscellaneous 



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