c. V. L. CHARLIER. TRIENTALIS EUROP.EA. 21 



A glance on these values shows that the length of the 

 stamen is generally increasing with that of the pistil, that 

 hence a correlation between these characters does exist. 

 Using the methods of »Grunddragen» p. 78 — which refers to 

 such cases, where the number of pairs is so small that a 

 distribution into classes is not appropriate — we find for the 

 coefficient of correlation the value: 



r = + 0,527 ± 0,236. 



The value obtained is, consequently, rather uncertain 

 owing to the small number of observations. 



We have found in § 12 and § 14 that the mean length 

 of the stamen is 4,4 7 (± 0,i6) and that of the pistil 4,3 6 

 (± 0,12). Within the mean errors we thus can consider the 

 mean length of the stamen to be identical to that of the 

 pistil. The value given above for the coefficient of corre- 

 lation permits us to state that, even for other than the 

 mean- valu es, the length of the stamen, to a certain degree, 

 follows that of the pistil. I allow myself to express the 

 opinion that a general investigation on the correlation be- 

 tween those characters for flowering plants seems to me to 

 be not without biological interest. 



16. Correlation between the thickness of the stem and the 

 length of the longest leaf in the rosule. 



There were 234 samples examined regarding this pair of 

 characters. The material was, regarding the thickness, distri- 

 buted into classes having a breadth of 0,io mm. {= w^), 



