CHAP. IV.] REPRODUCTION OF PLANTS. 149 



closed, self-fertilized flowers are called Gleistogamous. 

 The pansy {Viola tricolor) is the only British violet in 

 which seeds are produced generally by the old type of 

 flower; in the others, as the dog violet {Viola canina), 

 the sweet violet ( Viola odorata), etc., a few seeds may 

 occasionally be produced by the old type of flower, but 

 it has in reality been superseded by the cleistogamous 

 flower. The reversion to the self-fertilized method of 

 fertilization seems, and really is, unintelligible from the 

 present standpoint of knowledge, assuming that cross- 

 fertilization really invigorates and helps plants in the 

 struggle for existence, and judging from the proved 

 superiority of the offspring in the animal kingdom 

 resulting from parents having no blood -relationship, 

 this idea appears to be true ; nevertheless, in the case of 

 the violets and many other groups this is certainly the 

 direction in which things are tending at the present 

 day. If it be eventually demonstrated that what appears 

 to be self-fertilization in cleistogamous flowers, by some 

 modification in the stamens and ovules, produces equally 

 vigorous offspring as by the method of cross-fertilization, 

 then the change becomes intelligible, as the plant would 

 save the enormous amount of material at present necessary 

 for the purpose of attracting and supplying insects with 

 food. It may not be the pleasantest of ideas to realize the 

 possibility of the gradual disappearance of the showy por- 

 tion of the flower, but we are, or think we are, a self-sacrific- 

 ing race, and would not begrudge the loss of our favourite 

 flowers, if shown to be of advantage, even to plants. 



The various forms of Inflorescence, or massing of 

 flowers into dense clusters, have in many groups of 

 plants obviously been evolved, or, in other words, those 



