CHAPTER XIII 

 ROOTS 



138. General character. Roots are thought of as struct- 

 ures related to the soil. This is true of most roots, and it 

 is certainly true of the roots of those plants we cultivate. 



BBHHBBB 



A B 



FIG. 219. Roots : A, dandelion with tap-root ; B, grass with cluster of fibrous roots. 



However, there are also water roots and air roots, so that the 

 soil-relation is not the only one for roots, but this presenta- 

 tion will be restricted chiefly to soil roots. 



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