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 
fall 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 §6-%.— Fleshy Roots 
plant-food. Many such plants die to (About one-fifteenth 
the ground at the beginning of winter, ass 
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 
