202 THE POPULAR SCIENCE MONTHLY 

Fic. 6. RESULTS OF CROSSING TWO INBRED STRAINS OF Matzn, At the right 
average of the parents after three generations inbreeding, 61 bushels per acre. At 
the left crop of first generation cross of the inbred strains, 101 bushels per acre. 
them the grower obtains two strains and plants them in alternate rows. 
At flowering time all of the male flowers or tassels are removed from 
one of the plants of the-varieties before they shed their pollen. All the 
ears that these plants produce are crossed with the other variety. It is 
this seed that produces the vigorous plants. 
This method might be made the basis for some very valuable work 
in forestry. It is quite conceivable that many important timber trees 
might be found where nearly related species or varieties would cross 
readily. Experiment would show how great an increase in rapidity of 
growth could be expected, and whether such an increase would pay for 
the increased expense of hand hybridized seed. 

Fic. 7. SILVER HILL. Normal at left. Bud variation isolated by selection at 
ie the right. 
