250 Retrograde Varieties 



sharp limits between nearly related characters 

 must suffice. As Bateson has put it, species are 

 discontinuous, and we must assume that their 

 characters are discontinuous also. 



Moreover there is as yet no reason for trying 

 to make a complete analysis of all the charac- 

 ters of a plant. No doubt, if attained, such an 

 analysis would give us a deep insight into the 

 real internal construction of the intricate prop- 

 erties of organisms in general. But taxonomic 

 studies in this direction are only in their in- 

 fancy and do not give us the material required 

 for such an analysis. Quite on the contrary, 

 they comj)el us to confine our study to the most 

 recently acquired, or youngest characters, 

 which constitute the differentiating marks be- 

 tween nearly allied forms. 



Obviously this is especially the case in the 

 realm of the hybrids, since only nearly related 

 forms are able to give hybrid offspring. In 

 dealing with this subject we must leave aside 

 all questions concerning more remote relation- 

 ships. 



It is not my purpose to treat of the doctrine 

 of hybridization at any length. Experience is 

 so rapidly increasing both in a practical 

 and in a purely scientific direction that it would 

 take an entire volume to give only a brief sur- 

 vey of the facts and of all the proposed theories. 



