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** forma " names to structural peculiarities which we would, in 

 our broader view of nature, pass by as mere individual differ- 

 ences. I do not wish it to be supposed that I approve of any 

 such practice. From my point of view the terms " varietas " and 

 *' forma" need not be of different value in classification, although 

 in fact, they generally would be. It would be as difficult to de- 

 cide In some cases between ''species" and "forma," as between 

 '' species" and " varietas." There are, T believe, no structural dif- 

 ferences between Datura Tatula and D. Stravionium, but they 

 are believed to have originated in different parts of the world, and 

 the color character of the corolla is, so far as I am aware, constant. 

 There is little but the color of the flowers to separate the Ameri- 

 can Nasturium laaislre, Gray, from the European N. anipJiibium. 

 It appears therefore, that the very characters on which I would 

 base " forma," may be quite as constant as morphological ones 

 universally recognized as specific. , 



This brings up the whole question of what we should agree 

 upon as constituting a *' species." There are no fixed lines in 

 nature. The whole vegetable kingdom is so interlocked by the 



tendency to variation, working simultaneously with the efforts to- 

 wards atavism and heredity, that structures are continually pro- 

 duced which defy any system of classification. We are forced to 

 admit, and it ought to be further emphasized in our text books, 

 that intermediate forms may occur between any related groups 

 or individuals, or as Prof Oliver has put it, " no characters are 

 constant." It is, I believe, useless at the present stage of know- 

 ledge to argue that all *' species " are rigidly distinct and can be 

 separated by carefully drawn descriptions, if once their charac- 

 ters are understood. Some are naturally more permanent than 

 others, but this will not allow of a sweeping generalization- 

 It ought to be posssible, however, to adopt some considera- 

 tions which should guide us all in the elucidation of the prob- 

 lem, and this might well form a feature in an extended discus- 

 sion. But I do not propose to enlarge further on these general 

 matters at the present time. I wish to speak particularly of the 

 instances which have come under my observation in working out 



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