226 VEGETATIVE REPRODUCTION [CH. xvn 



There is good reason to suppose that, as Schenck 1 long ago 

 suggested, the vegetative reproduction of water plants merely 

 illustrates the general rule that vegetation and fructification 

 stand in inverse ratio to one another. Orchards bear better 

 when the trees are pruned, while in wet years when leafage is 

 over-luxuriant, fruit formation diminishes. And thus the 

 excessive vegetative activity of water plants acts, in all probabi- 

 lity, as a deterrent to sexual reproduction. 



i Schenck, H. (1885). 



