16 INTRODUCTION. 



The duration of flower and other roots is 

 commonly designated by the terms annual, bien- 

 nial, and perennial. 



Annuals, properly so called, are such as per- 

 petuate themselves by seeds only ; the whole 

 plant dying when these are perfected. Some of 

 this description, however, may be perpetuated by 

 art, perhaps, for ever, were it a necessary ex- 

 pedient ; for instance, the balsam among flowers, 

 and the melon and cucumber among cultivated 

 fruit. Annual bulbs are exemplified in the cro- 

 cus ; and annual tubers are such as the orchis 

 and potatoe. In these instances the identity 

 vanishes ; that is, the tuber of this year perishes 

 along with the leaves and stem, while a new 

 tuber or tubers are formed. Certain parts of 

 almost all plants are annual or temporary as to 

 existence ; the fibres, perhaps, of all plants which 

 are seasonal ; — bulbs and tubers as above noticed; 

 — the flower-stems of all perennial herbs ; — and 

 the leaves, flowers, and fruit of shrubs and trees. 

 We remember no instance of biennial roots 

 in the flower garden ; but, among culinary vege- 



