362 Origin of Each Species Considered Separately. 



From the systematic point of view therefore our 

 dwarf should be called Oenothera Laniarckiana nana or 

 as it is particularly small, 0. Lam. nanella. But from 

 the experimental point of view it behaves just like the 

 other elementary species ; for it is, as already stated in 

 § 3, absolutely true to seed. And as the name O. nanella 

 cannot refer to anything else I shall usually employ it.-^ 

 If we look a little more closely into it we shall find 

 other grounds for regarding our dwarf as an elementary 

 species. In the first place it is by no means a miniature 

 edition, as it were, of 0. Lamarckiana. 



Fig. 78. Oenothera nanella. A, a seedling with two 

 leaves ; c, the cotyledons. B, an older seedling 

 showing the long-stalked leaves or flag-leaves, of 

 the atavistic period, which appear next after the 

 first leaves. 



On the contrary it is, like the other new species, dif- 

 ferent from it in almost all its characters. It cannot be 

 mistaken for a weak plant of the parent species at any 

 time. Or to express it more emphatically, if we reduce 

 pictures of Lamarckiana and dwarfs to exactly the same 

 size we find that we can distinguish them by perfectly 

 definite characters. 



^ I recall in this connection Darwin's aphorism : Varieties are 

 only small species. 



