562 Mutations 



which of them was the progenitor of the others 1 

 Of course this could be done by long and tedious 

 crossing-experiments, showing atavism in the 

 progeny, and thereby indicating the common 

 ancestor. But even this capacity seems to be 

 doubtful and connected only with the state of 

 mutability and to be lost afterwards. Therefore 

 if this period of mutation were ended, probably 

 there would be no way to decide concerning the 

 mutual relationship of the single species. 



Hence the lack of a recognizable main stem in 

 swarms of elementary species makes it impossi- 

 ble to answer the question concerning their com- 

 mon origin. 



Another phase of the opposition between the 

 prevailing view and my own results seems far 

 more important. According to the current be- 

 lief the conversion of a group of plants growing 

 in any locality and flowering simultaneously 

 would be restricted to one type. In my own ex- 

 periments several new species arose from the 

 parental form at once, giving a wide range of 

 new forms at the same time and under the same 

 conditions. 



III. New elementary species attain their full 

 constancy at once. 



Constancy is not the result of selection or of 

 improvement. It is a quality of its own. It can 

 neither be constrained by selection if it is absent 



