CHAP TEE V. 



CONCLUDING REMARKS. 



The foregoing pages will suffice to show that the 

 relations between the forms of plants and those of 

 animals that feed on them are far more multifarious 

 than has hitherto been supposed'; and more especially 

 that numerous formations which occur on the leaves and 

 stem are far from being devoid of functional signifi- 

 cance, inasmuch as through them flowers are protected 

 against the disadvantageous assaults of certain animals. 

 Where the attacking animals are wanting, there these 

 defensive appliances are also, of course, meaningless. 

 Such formations, therefore, are to be regarded as means 

 of protection only when the plants are growing in their 

 original habitat in the district, that is, where the species 

 to which they belong has arisen. In any other situa- 

 tion these developments may perhaps not serve as 

 defences, nay they may be of direct disadvantage, or at 

 any rate may be a mere superfluity extraneous to the 

 economy of the plant ; and it is self-evident that such 

 unprofitably, because uneconomically, organised plants, 

 being placed under conditions not concordant with their 



