LECT. Y.] THE ROOT. 209 



from perfecting its seed. Thus I have preserved 

 the life of a Sweet Pea until after Christmas, when 

 it was destroyed by the severity of the weather, 

 by nipping off the flowers as soon as they were 

 fully blown ; and plants of tropical climates, which 

 are naturally biennial, sometimes live for many 

 years in our hothouses ; but they all invariably 

 die after they have produced fruit. The cause of 

 this is, that the vitality of the plants of this de- 

 scription seems to be sufficient for continuing their 

 life only till after the formation of the seed, the 

 natural means of perpetuating the species ; in per- 

 fecting which, the irritability and life of the in- 

 dividual are completely exhausted; and, with the 

 plant, the root perishes. In perennial plants, the 

 fibrils only annually perish and are renewed ; they 

 decay before the leaves fall in autumn ; and are 

 again formed in the early part of spring. At least 

 this is the opinion commonly received. The 

 root, however, enjoys more vitality than any 

 other part of the plant, and can reproduce all the 

 other parts, when the tree is cut down or otherwise 

 destroyed; except in the Pine tribe and some 

 other dry resinous plants. 



Such is the ROOT an organ of the greatest 

 importance, whether we consider it simply as fixing 

 the plant in the ground, and enabling it to elevate 

 its leaves and flowers in the air ; or, in a more 

 important point of view, as selecting and taking up 



VOL. I. P 



