90 THE SURVIVAL OP THE UNLIKE. [ill. 



which occasionally occur in full-grown plants in their 

 flower-buds or leaf -buds." A classical example is the 

 origination of the nectarine from a branch of a peach- 

 tree; and one often hears of Russet apples upon a 

 branch of a Greening apple tree, of weeping, varie- 

 gated or cut -leaved shoots on otherwise normal trees, 

 or of potatoes that "mix in the hill." Now, this mat- 

 ter of bud -variation has been a most, puzzling one to 

 all writers upon evolution who have touched upon it. 

 It long seemed to me to be inexplicable, but I hope that 

 you will now agree with me in saying that it is no more 

 unintelligible than seminal variation of plants, for I 

 have already shown that there is abundant asexual or 

 vegetative variation (of which bud -variation is itself the 

 proof), and that this variation takes place as readily 

 when the phyton is growing upon a plant as when it is 

 growing in the soil. The chief trouble in the consider- 

 ation of this subject has been that persons have ob- 

 served and recorded only the most marked or striking 

 variations, or those which appear somewhat suddenly 

 (although suddenness of appearance usually means that 

 the observer had not noticed it before), and that they 

 had, therefore, thought bud -variation to be rare and 

 exceptional. The truth is, as I have said, that every 

 branch or phyton is a bud -variety, differing in greater 

 or lesser degree from all other phytons on the same 

 plant. 



These differences, even when marked, may arise in 

 every part of the parent plant, as on stems aerial and 

 subterranean, from bulbs and tubers, or even from the 

 adventitious buds of roots; and the characters of these 

 varieties are as various as those originating from seeds. 

 The nurseryman knows that branches differ amongst 



