INTRODUCTION. 7 



to insects, it is a natural inference that their corollas 

 have been increased in size for this special purpose ; 

 and that their development has subsequently led, 

 through the principle of compensation or balance- 

 ment, to the more or less complete reduction of the 

 reproductive organs. But an opposite view may be 

 maintained, namely, that the reproductive organs 

 first began to fail, as often happens under cultiva- 

 tion,* and, as a consequence, the corolla became, 

 through compensation, more highly developed. This 

 view, however, is not probable, for when hermaphrodite 

 plants become dioecious or gyno-dioecious that is, 

 are converted into hermaphrodites and females the 

 corolla of the female seems to be almost invariably 

 reduced in size in consequence of the abortion of the 

 male organs. The difference in the result in these two 

 classes of cases, may perhaps be accounted for by the 

 matter saved through the abortion of the male organs in 

 the females of gyno-dioecious and dioecious plants being 

 directed (as we shall see in a future chapter) to the for- 

 mation of an increased supply of seeds ; whilst in the 

 case of the exterior florets and flowers of the plants 

 which we are here considering, such matter is expended 

 in the development of a conspicuous corolla. Whether 

 in the present class of cases the corolla was first af- 

 fected, as seems to me the more probable view, or the 

 reproductive organs first failed, their states of develop- 

 ment are now firmly correlated. We see this well illus- 

 trated in Hydrangea and Viburnum ; for when these 

 plants are cultivated, the corollas of both the interior 

 and exterior flowers become largely developed, and 

 their reproductive organs are aborted. 



* I have discussed this subject xviii. 2nd edit. vol. ii. pp. 1 52\ 

 in my 'Variation of Animals and 156. 

 Plants under Domestication,' chap. 



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