i;8 EXPERIMENTAL EVOLUTION LECT. 



tion is of recent origin ; among the radishes consider- 

 able differences obtain, whatever their original form 

 may have been ; and the same is true of carrots, lettuce, 

 strawberries, peaches, pears, apples, oranges in fact, 

 of every cultivated species we are acquainted with. 

 In all these species, and also in all plants which are 

 cultivated for the sake of their flowers, or because 

 they provide drugs which are of use to man, in all 

 vegetable species, in short, which mankind cultivates 

 for some reason or other, numerous varieties exist, 

 and in many cases we meet with twenty, thirty, or 

 forty varieties, if not even more, in the same species. 

 These varieties man is responsible for : he has made 

 them, he has evolved them out of the species, and 

 some are of very recent origin, such as the Brussels 

 sprouts, for instance some were made yesterday, and 

 others will appear to-morrow. The process may be 

 indefinitely varied, and so long as man cultivates 

 plants he has the right to expect to create new 

 varieties. The method used in such creations is no- 

 wise mysterious, and all breeders, horticulturists, and 

 gardeners are acquainted with its application. 



The mere enumeration of our garden vegetables, 

 fruit trees, commercial and industrial plants, garden 

 trees and flowers, and even their names show that 

 variability exists amongst cultivated plants as well 

 as among the wild species, and in plants generally 



