INFLUENCE OF CULTURE ON VEGETATION 283 



selves bear no resemblance : thus, the Salicaria loves to 

 grow at the foot of the willow: the Monotropa, at the foot of 

 the pine ; the Saxote, to grow amongst oats. 



Emily. What can be the reason of this singular kind 

 of attachment of one species of plants for another ? 



Mrs. B. Several have been assigned : first, that plants 

 of different species frequently require the same soil ; the 

 next (of a more doubtful nature) is, that the exudations 

 of some plants may promote the growth of others of a 

 different species ; a third reason alleged is, that certain 

 plants often serve to protect others of a different species, 

 as hedges and bushes protect the creeping plants which 

 grow between their branches. 



Emily. It appears, then, that we can in some degree 

 explain that prodigious mixture in the vegetable kingdom, 

 in which at first I thought there was no sort of order. 



Mrs. B. There is always order in the works of Na- 

 ture ; and what appears to us disorder is the result of dif- 

 ferent laws acting at the same time. By following the 

 mode of reasoning I have pointed out to you, and by 

 constantly comparing the structure and the habits of plants 

 with the nature of the soil in which they grow, a great 

 number of curious facts may be explained. I am glad to 

 have drawn your attention to this subject ; it will be a 

 source of amusement in your walks : and the greater the 

 number of plants you become acquainted with, so as to 

 be enabled clearly to distinguish their different species, 

 the more interesting will your observations prove. 



CONVERSATION XXV. 



ON THE INFLUENCE OF CULTURE ON VEGETATION. 



Mrs. B. Let us now examine to what extent the nat- 

 ural state of plants can be modified by the art of man. 

 For this purpose it will be necessary for me to make you 

 acquainted with certain differences which exist in plants 

 of the same species. 



1527. What reasons have been assigned for this singular fact in botan- 

 ical science! 1528. What advantage does Mrs. B. think will result 

 to her pupils from the knowledge of botany they are acquiring! 1529. 

 What is the subject of the 28th Conversation! 



