2i ;n 



THE AMERICAN NATURALIST [Vol. XLII 



IV. Nomenclature and Treatment of New Forms 

 Enough has been said to indicate clearly the ecologist's 

 view of species, both valid and otherwise. He is vitally 

 interested in the species' ancestry, its method of origin 

 and the factor concerned, as well as in the result, which 

 is the species or form itself. Until his experimental 

 study of these points makes it possible to distinguish 

 species from minor groups, or shows that the species 

 concept is a mistaken one, it is useless to debate whether 

 the resulting form is a species or not. In fact, the status 

 of the result must await the determination of ancestry 

 and origin in every case, and we may well call all the 

 results forms until this has been done for each. 



The question of ancestry resolves itself at the outset 

 into one of old forms or of forms newly produced. The 

 production of a new form from an old or existing one 

 by properly checked experiment at once gives the an- 

 cestry of the former. Here, where the whole experiment 

 is under our control from beginning to end, we may con- 

 centrate our attention upon the method of origin and 

 the factor concerned. The discovery of the ancestor of 

 an existing form or species is often a much more difficult 

 matter. Until the ancestry is determined, it is useless 

 to try to ascertain the method of origin, and the factor. 

 When the form bears the distinct stamp of sun or shade, 

 of a wet or dry habitat, or of hybridation, etc., our search 

 is narrowed at once to deciding what species gives the 

 most promise of being the parent form. When there is 

 no distinct stamp, we must first look for the most promis- 

 ing species, and then try the various methods and factors 

 experimentally until the form sought is produced. How 

 often the ancestry and origin of accepted species can 

 be worked out in this way remains to be seen. Results 

 already obtained show that this method works perfectly 

 in the few cases tried, and that it may be expected to 

 prove successful in many cases. When a complete series 

 of trials of suspected parents does not give the form 

 sought, it seems fair to assume that these and the species 



