Ill 



THE PLANT AS A HOST 



APART from the food and shelter provided by 

 vegetation to animal life, one is not perhaps ac- 

 customed to think of the plant in its character 

 as a host. Yet the question of entertaining guests 

 enters largely into the existence of many species, 

 and is a much more important matter than 

 might at first be supposed. In considering the 

 relations of the flower and the living agents 

 which carry the pollen, we shall see how well the 

 plant is able to reward those willing to render 

 the required aid, but in the present chapter it 

 is proposed to consider some far more intimate 

 alliances. In some cases it is possible to show 

 that the connections are of direct benefit to both 

 the parties concerned the plant providing housing, 

 and even food, in return for services rendered. 

 Other instances are more puzzling, in that although 

 the plant does not appear to derive any advant- 

 ages from its guests, yet it is willing to tolerate 



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