July, 1921] 



THE SEEDLING OF PHASEOLUS VULGARIS 



353 



TABLE 4. Differences between correlations for three classes of bundles at base of hypocoiyl 

 and the number of bundles in the central regions of hypocotyl and epicotyl, respectively 



epicotyl of the plant. The correlation surfaces are given in tables A-L. 

 The results are set forth in table 5. 



TABLE 5. Coefficient of correlation between number of bundles in central region of hypocotyl 



and central region of epicotyl 



The correlations are positive with the exception of that for dimerous 

 plants of line 75 and of that for both dimerous and trimerous plants of 

 line 139, which are negative in sign. Only one of the negative coefficients 

 may be considered statistically significant in comparison with its probable 

 error. Several of the positive coefficients are large enough in comparison 

 with their probable errors to be considered possibly significant. The 

 average correlation for the trimerous plants is +.074 while that for the 

 dimerous plants is +.058. The correlations for the trimerous and dimerous 

 plants can not be considered to differ significantly. 



The generally positive sign of the constants suggests that seedlings 

 which have a larger number of bundles in the hypocotyl have on the average 

 a larger number of bundles in the epicotyl. This is the condition actually 

 found in the series studied, but the difficulties in the interpretation of the 

 probable error in cases in which the correlation coefficient is so small should 

 make one cautious in generalizing the results obtained. 



How slight the relationship between the numbers of bundles in the two 

 organs is, may be shown by the regression lines giving the change in the 

 mean number of bundles in the epicotyl associated with variations in the 



