ROOTS 



47 



58. Use of the Food stored in Fleshy Roots. — The 



parsnip, beet, carrot, and turnip are biennial plants ; that 

 is, they do not produce seed until the second summer or 

 faR after they are planted. 



The first season's work consists mainly in producing the 

 food which is stored in the roots. To such storage is 

 due their characteristic fleshy appear- 

 ance. If this root is planted in the 

 following spring, it feeds the rapidly 

 growing stem which proceeds from the 

 bud at its summit, and an abundant 

 crop of flowers and seed soon follows; 

 while the root, if examined in late sum- 

 mer, will be found to be withered, with 

 its store of reserve material quite ex- 

 hausted. 



The roots of the rhubarb (Fig. 22), 

 the sweet potato, and of a multitude of 

 other perennials, or plants which live 

 for many years, . contain much stored 

 plant-food. Many such plants die to 

 the ground at the beginning of winter, 

 and in spring make a rapid growth from the materials laid 

 up in the roots. 



59. Extent of the Root-System. — The total length of. 

 the roots of ordinary plants is much greater than is usually 

 supposed. They are so closely packed in the earth that 

 only a few of the roots are seen at a time during the 

 process of transplanting, and when a plant is pulled or dug 

 up in the ordinary way, a large part of the whole mass of 

 roots is broken off and left behind. A few plants have 



Fig. 22.— Fleshy Roots 



of Garden lihubarb. 



(About one-fifteenth 



natural size.) 



