III. THE SYSTEMATIC VALUE OF THE NEW 



SPECIES. 



§ 24. THE NATURE OF THE BOUNDARIES BETWEEN 



RELATED SPECIES. 



It follows directly from the doctrine of mutation 

 that the species which arise by mutation are as sharply 

 distinguished from one another as are neighboring spe- 

 cies of recognized systematic value. 



The previous chapter has shown us that new species 

 are, as a rule, from the very beginning as constant as 

 other species. This constancy is manifested in two ways. 

 In the first place the various individuals of the new spe- 

 cies are absolutely alike in all their essential features: 

 and this is true not only of the offspring of new muta- 

 tions and of others which arise from the same parents, 

 but also of the hosts of mutations which have arisen 

 from widely separated and independent families of the 

 same parent species. In the second place they come true 

 to seed, they do not revert to the parent form. If the 

 latter character is absent as in the case of Oenothera 

 scintillans the new form cannot be capable of existence 

 in nature and therefore cannot be compared with true 

 wild species. 



The object of the present chapter is to show that the 

 characters of the new species which have arisen in the 



