140 



ROOTS 



Fig. 125. — Sugar Beet, a 

 plant with a fleshy tap-root. 



and the Dandelion, where the shoots die down in the fall to be 

 followed b}' new ones in the spring. Thus the tap-root sj^stem 

 is well adapted to the perennial habit. In some plants, as 

 Radishes, Beets, Carrots, Turnips, 

 etc., where the storage function is 

 quite prominent, the tap-root is 

 tender and of much importance as 

 a vegetable. {Fig. 125.) From some 

 fleshy roots valuable products are 

 extracted, notably the Sugar Beet 

 from which most of our sugar is ob- 

 tained. 



Plants having prominent tap-roots 



with short lateral roots can be grown 



close together without injury. Due 



to this fact and to the size of the 



shoot, such plants as Clover, Alfalfa, 



Beets, and others with the tap-root 



system grow well when crowded. 



The fascicled root-system, consisting of a cluster of roots all of 



which are much enlarged in connection with the storage of food, 



is characteristic of a few plants of which the Sweet Potato and 



Dahlia are two that are well known. {Fig. 126.) 



Adventitious roots, so named because of their occurrence in un- 

 accustomed places, may be 

 mentioned here, although 

 the classification pertains 

 to the place of occurrence 

 and not to any peculiar fea- 

 ture of the root itself; for 

 any root, whether fleshy or 

 fibrous, developing from 

 leaves or from stem regions 

 where roots are not nor- 

 mally present is called ad- 

 ventitious. All roots may 

 be regarded as adventitious 

 except those, known as the primary ones, which develop directly 

 from the radicle of the embryo. 



The ability of many shoots to develop roots from various re- 



FiG. 126. — A portion of a Sweet Potato 

 plant, showing the fascicled roots. 



