THE WAY IN WHICH NEW PLANTS ARISE 133 



horse radish, and put in moist sand or soil. Stems 

 and leaves will be seen to appear after a time. The 

 ability to replace the other members of the plant 

 by the root is not very common. It is shared, how- 

 ever, by beech, cherry, poplar, and some coniferous 

 trees. 



183. Structures used by plants as means of vege- 

 tative reproduction. Plants have many devices by 

 which portions of the roots, stems, and leaves take 

 on special forms and become separated from the 

 parent plant in a manner which allows them to form 

 a new individual. Chief among these structures are 

 "bulbs (see 167), bulbils, tubers, offsets, stolons, besides 

 many special forms. 



184. Tubers. A tuber consists of a portion of 

 an underground stem which serves as a storehouse 

 for surplus food, and which is capable of reproduc- 

 ing the plant by the growth of its buds, which are 

 usually several in number. Examine the base of a 

 vigorous potato stem by digging away the soil. Be- 

 sides the roots will be found numbers of thickened 

 stems or potatoes. Note the "eyes," or buds, on 

 the surface. Are they most abundant on the end 

 toward the main stem or the apical end? 



