74 Plant-Breeding 



version of a group of plants growing in any locality and 

 flowering simultaneously would be restricted to one type. 

 In my own experiments several new species arose from 

 the parental form at once, giving a wide range of new forms 

 at the same time and under same conditions." 



3. New elementary species attain their full constancy 

 at once. 



" Constancy is not the result of selection or of improve- 

 ment. It is a quality of its own. It can neither be 

 constrained by selection, if it is absent from the beginning, 

 nor does it need any natural or artificial aid if it is present." 



No atavism was exhibited by the primrose mutations 

 with the exceptions of (E. sdntillans and (E. elliptica. 

 These latter types reproduce themselves only in part in 

 the offspring. De Vries says that the instability in these 

 types seems to be as permanent a quality as the stability 

 of the other forms. 



4. Some of the new strains are evidently elementary 

 species, while others are to be considered as retrograde 

 varieties. 



Such new forms as (E. gigas, rubrinervis, oblonga, and 

 albida may be called new elementary species. They are 

 not differentiated from Lamarkiana by one or two main 

 features, but they differ from it in nearly all organs, and 

 hence may be considered new elementary species. The 

 differences exist, not only in the foliage where they are 

 most manifest, but in the stems, flowers, seeds, and in- 

 deed, in many instances, to the minutest cell structure. 



(E. Icevifolia, (E. brevistylis, and (E. nanella, on the 

 other hand, may be considered as retrograde varieties. 

 They seem to differ from the parental form in but one 



