LUMBER TREES 115 



to support this evidence, and in doing so to reveal 

 additional reasons for belief that the same prin- 

 ciples will apply to other forest trees, by recall- 

 ing briefly the story of the vicissitudes through 

 which the existing trees have passed and through 

 which the diversified hereditary factors were im- 

 planted in their racial heredity. 



A knowledge of this story we owe to the 

 geological botanists. They have sought dili- 

 gently in the rocks for fossil remains, and by 

 joint effort, searching all around the world, 

 have been able to reproduce a picture of the 

 main story of the evolution of existing forms 

 of vegetable life. 



It is by recalling the story which they tell us, 

 and thus alone, that we are enabled somewhat 

 clearly to apprehend the possibilities of variation, 

 and through variation of so-called new develop- 

 ment consisting essentially of the recombina- 

 tion and intensification of old ancestral traits 

 that we have witnessed in the case of many tribes 

 of plants in the course of our experiments. 



A brief resume of this story of plant life in the 

 past, with particular reference to our own flora, 

 will serve in the present connection to explain 

 why there is every warrant for believing that 

 each and every one of our forest trees contains 

 submerged in its heredity the potentialities of a 



