Contents 



CHAPTER 



XXXI. 



XXXII. 



XXXIII. 



XXXIV. 



XXXV. 



XXXVI. 



XXXVII. 



XXXVIII. 



XXXIX. 



XL. 



XLI. 



XLII. 



XLIII. 



XLIV. 



XLV. 



XL VI. 



XLVII. 



XL VIII. 



XLIX. 



L. 



Index 



Hybridization and Selection 



The Distribution of Plants in Nature 



The Vegetation of North America . 



Relation of Plant Industries to Climatic Plant 



Formations 



Weeds and Their Control . 



The Non-Green Plants 



Bacteria and Their Relations to Life 



Soil Bacteria and the Nitrogen Cycle 



Fungi 



Plant Diseases 



The Classification of Plants . 



The Alg^ 



Bryophytes: Liverworts and Mosses 

 The Pteridophytes .... 



Fossil Plants 



The Gymnosperms — Cycads 



The Gymnosperms — Conifers 



The Angiosperms or Flowering Plants 



Some Families of Angiosperms . 



Evolution of Plants .... 



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302 



310 



375 

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423 

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465 

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 508 



517 

 524 

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553 



