MAKING NEW KINDS OF PLANTS 417 



the seed altogether, he does not consider it desirable 

 to do so, for the reason that the seed adds flavor to 

 the cooked prune. 



These astonishing results represent but a portion 

 — indeed a minor portion — of the achievements of 

 one man during a few years of work, and they afford 

 an excellent illustration of the possibilities of plant- 

 breeding. The method by which they have been 

 brought about is simplicity itself: variation and selec- 

 tion are the two processes which produce all these 

 results. We may now examine them more in detail. 



It is a familiar fact that every plant shows some 

 variation (since no two plants, or leaves even, are 

 alike), and it has been discovered that variation obeys 

 certain laws. It not only confines itself within certain 

 limits, but there is a certain average form or type 

 around which the variations group themselves. This 

 may be made clear by means of a diagram. If we 

 count the number of rays^ in a large quantity of 

 daisies (the Common Ox-eye Daisy), we may find that 

 it varies, let us say, from five to thirty- seven. If we 

 sort them into piles, putting into the first pile all those 

 with five petals, into the second all those with six, 

 and so on, we shall find that the pile containing 

 those with twenty -one petals is the largest. If, now, 

 we string the daisies in each pile on an upright wire, 

 so as to form vertical columns of them, we shall get 



I The rays are the white outer parts, usually called "petals." 

 AA 



