Further Evidence against the Origin of Species by 



Infinitesimal Variations. library 



NEW YORK 

 ^^ BOTANICAL 



J. C. WILLIS. GARDEN. 



ON thinking over the argument given in my last paper 

 on page 8 of this volume (" In the fourth place, &c."), 

 further reasons against the possibilit}^ of the origin of species 

 by infinitesimal variation have occurred to me, which may be 

 briefly given here. 



A point that has so far escaped attention, to my knowledge, 

 is that while the characters that distinguish species and genera 

 are largely characters of the floral organs, the struggle for exis- 

 tence is almost entirely among the seedlings and young plants, in 

 which these organs are not yet present. 



Once the plant has reached the stage of flowering, there is, 

 in the enormous majority of cases, no struggle for existence 

 worth mentioning between it and the other members of its 

 species, at any rate no such struggle as will kill out, say 75 

 per cent., and enable those with any given character strongly 

 marked to survive. I very much doubt whether any evidence 

 could be brought forward to prove that even 25 per cent, were 

 killed out at this stage, and that being so, it is evident that the 

 gain in any one character must be almost indefinitely less, on 

 the old theory, than it is conceivable that it might be if all but 

 those with that character strongly marked were to go under. 



To take an example, is it conceivable that in Dillenia it can 

 make any difference to the seedlings whether their leaves are 

 acute or obtuse, or the petioles 1 or 1| inch long, and yet 

 these are the only characters that can show till the plants are 

 at least ten years old, by which time aU that are going to die 

 ^ out will have done so, and the survivors will have grown into 



^~~ [Annals of the Royal Botanic Gardens, Peradeniya, Vol. IV., Part II., October, 1907.] 



^ 7(8)07 (2) 



