i86 



Science of Plant Life 



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U. S. Forest Service 

 Fig. io6. Typical section of a mountain slope in western North Carolina, after 

 removal of forest. The binding effects of the roots have been removed, and the erosion 

 of the soil is so rapid that it is diiTicult for seedlings to take hold. When the forest was 

 cut, enough young trees should have been left to hold the soil and start a new lumber crop. 



ever, that even in perennial roots the work of absorption is 

 for the most part done by the new roots which are added each 

 year. Most biennials, Hke the common evening primrose 

 and wild carrot (page 315), have fleshy roots in which food 

 accumulates during the first year. This food is used in the 

 rapid development of the plant during the second season. 



Ecological types of roots. Most of the root characteristics 

 thus far described are those of the roots of mesophytes. In 

 hydrophytes, or water plants, the roots are notably smaller 

 and less branched than in mesophytes. They absorb water 

 and mineral substances from the soil even when the plants 



