32 MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 



One of the things of first interest that will be looked for in this table is the 

 relation of the fluctuation found in different lots of plants of the same species. 

 Particularly is it interesting to compare the conditions of entry a with entry 

 b, the first representing Oenothera lamarckiana self-fertilized for sixteen genera- 

 tions, the second the same species which has never been self-fertilized, except 

 as that process may have taken place by natural causes. 



One represents i6 generations of artificial selection, the other many genera- 

 tions of natural selection, but in neither case is it probable that the propor- 

 tionality in the parts of the bud entered into the selection in any specific way. 

 In the mean values of the several parts, these two lots of plants are found to be 



Fig. 10. — Correlation in the buds of OenoUiera lamarckiana, Xo. 04129. Length of 

 ovary subject, length of hypanthium relative. Coefficient of correlation, 0.4215 ± 



0.0441. 



identical only in regard to length of hypanthium and length of cone. Consid- 

 erable differences are to be seen in length of ovary and thickness of cone, and 

 slight differences in thickness of ovary and of hypanthium. In the standard 

 deviation and coefficient of variability, on the other hand, there is essential 

 identity in every character except in the thickness of the cone, which was 

 significantly more variable in the self-fertilized plants. There are too many 

 possible sources of such difference to make any speculation regarding its 

 significance profitable at this time. 



When the data in the third entry (c'), is compared with those in the first 

 and fourth entries, the very interesting fact develops that in certain charac- 



