122 



AGRICULTURAL BOTANY 



or rootlets, it is called a fibrous root. Nearly all grains 



and grasses have fibrous roots. 



Some roots are storehouses of 

 food for the nourishment of the 

 plant itself and the production of 

 seed the following year. They 

 consist of a large main root with 

 small side branches. Such roots 

 are called fleshy roots, or taproots. 

 The carrot and turnip are good 

 examples. (See Figure 44.) 



Note. Parasitic roots. Another class 

 of roots, based on mode of feeding rather 

 than on* form, is called parasitic roots. 

 These roots are found on such plants as 

 mistletoe and the common dodders, which 

 grow on flax, clover, alfalfa, and other 

 plants. These are 

 peculiar roots 

 which penetrate 



the tissues of the plants upon which they live, 



taking their nourishment from these plants. 



Root Hairs. - - Figure 50 shows 

 some very young radish plants. No- 

 tice that each root is clothed with a 

 downy fringe that looks like the finest 

 silk. These delicate, hairlike struc- 

 tures are called root hairs. The pur- 

 pose they serve is to absorb the soil 

 water with the food materials it con- 

 tains. The root hairs greatly in- 

 crease the absorbing surface of the plant below ground. 

 Each root hair consists of a single elongated cell, 



FIG. 49. Roots of an Oat 

 Plant, showing Fibrous 

 Root. 



FIG. 50. Young Rad- 

 ish Plants. 



