108 AGRICULTURE ON THE PACIFIC SLOPE 



ing primroses, which make new_ kinds (mutations) 

 wREout any assistance from man; and no doubt many 

 other plants do so. This process is called mutation. 



How can we make new kinds of plants ? When we 

 take away all the pollen from a flower before it has a 

 chance to act on that flower, and then place upon the 

 stigma of the flower pollen from another kind of plant, 

 we make what is called a cross; and the seed produced 

 by that flower gives a plant called a hybrid. This may 

 be much better than either of the parents. 



FIG. 58. The improved beach plum is shown in the center. Its parents 

 are shown on either side, an American plum at the left, and the beach 

 plum at the right. Natural size. 



An American plum was crossed by Mr. Burbank 

 with a small worthless beach plum which grows wild 

 along the seashore. The result of the cross is shown in 

 figure 58. The fruit has the good qualities of both 

 parents. It has a fine flavor without any trace of the 

 bitter taste of the beach plum. And it has the hardi- 

 ness of the beach plum, and will grow in all kinds of 

 soils where the American plum could not grow. It will 



