ECONOMIC USES OF ROOTS 
255 
above the soil. This enables them to absorb and to store 
up the scanty moisture. 
222. Economic Uses of Roots. — In some plants the root is 
the most valuable part for food not only for man but also 
for his animals. Examples of this are many of the garden 
Figure 245. — Root System of Rhubarb, a Medicinal Plant. 
Food'is stored in the larger parts. Many of the rootlets have been broken off. 
vegetables, such as carrot, parsnip, turnip, vegetable oyster, 
and beet. The food stored in the beet is rich in sugar, 
making it one of the sources of the sugar of commerce as well 
as a valuable food for stock. Other roots furnish substances 
used as medicine when they have been extracted, as rhubarb 
