342 Origin of Each Species Considered Separately. 



plants are arranged in rows in the boxes : 0. albida can 

 be recognized at once in the middle of the figure by its 

 small size; just underneath it is the 0. ohlonga which 

 can hardly be distinguished in the figure. I transplanted 

 these two plants on to a separate bed to watch their further 

 development. They grew up to strong rosettes which 

 exhibited all the characters of the species to which they 



Fig. 72. A mutation in a culture of O. Lamarckiana. Ori- 

 gin of O. albida and O. ohlonga. From a photograph 

 taken at the end of May 1900. In the middle of the 

 middle row is the little O. albida ; in the middle of the 

 lower row O. ohlonga. The other seedlings are O. La- 

 marckiana ; Vs natural size. 



belonged, clearly and beautifully; but were destroyed in 

 the autumn by the caterpillars of Agrotis segetum. 



Seedlings of even less than 6 or 8 leaves can often 

 be recognized ; but it is very difficult to describe the 

 characters which render their identification possible. In 

 Fig. 73 at A 3. very young seedling is shown with its 



