22 



AKKIV FÖR BOTANIK. BAND 12. N:0 14. 



regarding the length of the leaf into classes with a breadth 

 of 6 mm. 



Thickness of the stem 



I 



At the head of each column and row is inscribed the 

 mid-value of each class in millimeters. The value of the 

 coefficient of correlation, computed according to the method 

 of »Grunddragen» p. 84, w^as 



r = + 0,829 ± 0,036, 



SO that a rather strong and well determined correlation exists 

 between these two characters. 



Simultaneously with the coefficient of correlation even 

 the values of the means and the dispersions were computed. 

 As, however, the values of these characteristics were evaluated 

 from a somewhat more extensive material in §§ 7 and 9, it 

 is not needed to cite here the values obtained. The agree- 

 ment with those values was, indeed, as good as might be 

 expected from the mean errors. 



17. Correlation between the length of the flower-stalk and 

 the length of the longest leaf in the rosule. In this respect 139 

 samples were examined. The result is given in the following 

 correlation-table. 



