Cross- versus Self-fertilisation 



assumption that cross - fertilisation is advan- 

 tageous to plants. It is questionable whether 

 this assumption is justified. True it is that 

 numbers of experiments have been performed, 

 which show that, in many cases, flowers which are 

 artificially self-fertilised yield comparatively few 

 seeds. But experiments of this kind do not 

 prove very much. 



To place on the stigma pollen from the anthers 

 of the same flower, in case of a plant which for 

 many generations has been cross-fertilised, is to 

 subject the plant in question to a novel experi- 

 ence an experience which may be compared to 

 transplanting it to another soil. The immediate 

 effect may appear to be unfavourable, although, 

 if the experiment be persisted in, the ultimate 

 results may prove beneficial to the plant. 



That this is the case with some flowers that 

 are artificially fertilised is asserted by the Rev. 

 G. Henslow. This observer states, that had 

 Darwin pursued his investigations further, he 

 would probably have modified his views regard- 

 ing the benefits of self-fertilisation. Darwin's 

 statement that " Nature abhors perpetual self- 

 fertilisation " seems to be as far from the 

 truth as that which declares " Nature abhors a 



vacuum." 



From the mere fact that cross-fertilised flowers 

 yield a greater quantity of seed than they do 

 when self- fertilised, it does not necessarily follow 



259 



