14 INTRODUCTION. 



the growing parts derive any benefit from the 

 outer covering, except protection ? most probably 

 none. With the new bulb the older one, which 

 is in the act of expanding, has no other con- 

 nexion than being seated on the same base. 



From the fibrous roots chiefly, and from the 

 qualities and influences of the air on the exposed 

 parts, are derived all the nutriment required by 

 the expanding parts, as well as the smaller por- 

 tion required by the incipient bulb. When the 

 stem and leaves are withered, their bases are 

 compressed and pushed aside by the new-formed 

 bulb, and their wasted remains are lost in the 

 exterior envelope. The tulip is not, like the 

 foregoing, constantly invested with the remains 

 of former leaves ; they are completely exhausted 

 in the summer growth, and the new bulb is only 

 left covered by a thin integument. 



The changes which take place in permanent 

 tubers, such as the anemone, are not so easily 

 detected as those in bulbs. That they are not 

 diminished in volume by the production of their 

 summer growth is manifest from the circum- 



