ASPECTS OF THE SPECIES QUESTION 



277 



may-be twenty to thirty feet from the edge of the water, 

 making their way even along paths or roads. Now, I 

 want to say, I do not know that they did not exist before 

 that, but I never noticed them until then; and not a mile 

 or two miles from here, if there are vacant lots, you will 

 probably find Polygonum harttrrightii in a drained 

 slough, where twenty to twenty-live years ago you would 

 not find anything of that kind, but you would find 

 Polygonum amphibium. It seems to me that is the way 

 in which it might have originated here. This experience 

 extends from about 1875, and although I gather from it 

 that it was not here before, I believe that it made its 

 appearance not far from 1890 to 1895. 



Mil G. II. Skull: In one sense the recent discoveries 

 in the realm of variation and heredity appear to lead 

 to a backward step in the concept of a species, since the 

 view of the naturalness of species to which these discov- 

 eries lead, resembles the earlier view. Upon a com- 

 parison of the basis of this conception, however, in the 

 time of Linnams, with the present situation, the contrast 

 becomes siit'licicnl \y st riking. 



At that time no cognizance was taken of the importance 

 of variations. When variations were first fully taken 

 into account, about the middle of the last century, they 

 were apparently conceived to have no natural limits, and 

 in consequence, no form-group could have natural limits. 



has shown that the lowest grade of form-group is a 

 natural group of individuals differing from each other 

 only by fluctuations. It appears to me that the able dis- 

 cussions to which we have listened might all be reduced 

 to the question of the desirability or feasibility of looking 

 upon these ultimate, natural 'form-groups 'as species. 

 This question largely rests upon the question of utility, 

 and herein lies our difficulty in reaching a universally 

 satisfactory conception. To the maker and keeper of 

 herbaria and to the field naturalist, utility requires that ' 

 species shall be separable by characters which may be 



