Growth and variation in maize. 171 



tilized maize plants. These factors would occur in the proi)ortions 

 found in a stable Mendelian population mating; at random. 



5. By assuming the presence of two independent growth factors 

 and weighting each with the proper value, it is possible to obtain a 

 theoretical distribution agreeing verj' closely with the observed distri- 

 bution. It is possible that by using more factors even a better fit 

 might be obtained. 



6. The interpretation of the growth of these ])lants by Mendelian 

 factors is strongly supported by the distribution of the standard devia- 

 tions of the plants with different relative sizes. Thus it has been 

 shown that the extreme plants which would be more nearly homozygous 

 and for this reason less variable are, as a matter of fact, some fifty 

 percent less variable than the plants in the middle class after all allow- 

 ance has been made for the difference in the size of the means. 



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