82 



SOILS AND PLANT LIFE 



obstacles, seeking for food and moisture. It must there- 

 fore follow a somewhat snakelike indirect course. Even 

 so, this wandering sort of growth would be impossible 

 were not the root peculiarly adapted for it in two ways : 

 (1) The end of the root is protected by a sort of cap. 



(2) Growth in length 

 takes place only in the 

 region just back of this 

 cap. 



This arrangement en- 

 ables the young root to 

 "feel" its way among the 

 soil particles with the deli- 

 cate cells at the end pro- 

 tected ; and it is not shoved 

 or pushed forward as it 

 would be if growth in 

 length took place at any 

 considerable distance back 

 from the tip. 



The root hairs appear 

 only in the region of growth. 

 They grow in the moist air 

 between the particles of soil, 

 with which they come in 

 contact and against which 

 they flatten themselves 

 that they may take up the film of moisture with which 

 these particles are covered. 



Fig. 26. — A root hair in con- 

 tact with soil particles (very much 

 enlarged) . 



59. The Extent and Depth of Roots. — The first thing 

 to know in the cultivation of any crop, after learning the 

 soil and seed bed requirements, is the nature of the root 

 system of the particular plant. Shall we give deep culti- 



