THE WINTER RHUBARB 103 



habits of the species would become so variable 

 and desultory that racial continuity would be 

 endangered. 



So the individuals of a generation throughout 

 a large region were sacrificed to a racial instinct 

 which in the main was beneficial to the species. 

 It will be clear, I trust, how this illustration 

 bears directly on the case of our winter rhubarb. 



RESTORING SUBMERGED INSTINCTS 



It could make no difference to the roots of this 

 plant that they had been unwittingly trans- 

 planted from a land where winter comes in July 

 to a land where that month betokens summer. 

 The instinct of bearing at that particular season 

 had all the force of the instinct that impels the 

 bird to migrate at a given time ; and this instinct 

 could by no chance be repressed in a given gener- 

 ation, any more than the martins could make 

 over their migratory instinct to fit a transitory 

 condition. 



But all this leaves quite unexplained the other 

 fact, which bore so important a part in our story, 

 that the New Zealand rhubarb when transplanted 

 to California assumed a new habit of bearing 

 during the cold season of the Northern Hemis- 

 phere which corresponded to the summer of its 

 original habitat and therefore to a calendar 



