CORRELATIONS IN NOTHOSCORDUM AND ALLIUxM. 113 



The significance of linear regression in the present cases is 

 two-fold. First, it shows that we are quite justified in using 

 the coefficient of correlation to describe the degree of inter- 

 dependence of length of flowering stem and number of flowers 

 per inflorescence. Second, it shows our material to be in 



DIAGRAM II. ALLIUM. 



SLOPE OF REGRESSION STRAIGHT LINE. 



this respect in agreement with the vast majority of organic 

 relationships, for in most cases of organic correlation regres- 

 sion is sensibly linear. 



In short the high positive values of r and the apparently 

 linear regressions indicate that in this material the length of 

 the stalk and the number of flowers per umbel are intimately 

 associated and that the rate of change in the number of 

 flowers as we pass from the shortest to the longest stalks 

 remains practically the same throughout the entire range of 

 variation of the latter character. 



