762 THE AMERICAN NATURALIST. [Vol. XXXVII. 



Still another major difference between the forms in general 

 habit is that of the method of branching and the growth of the 

 branches. In Qi. lamarckiana, the branches from the basal por- 

 tion of the shoot were of a length amounting to more than half 

 that of the shoot which is also true of GL. riibrinervis. The 

 upper branches of the former remain short and stout however, 

 while those of rubrinervis attain greater lengths which decrease 

 upwardly so that a plant may have a roughly globular outline. 



The majority of the features in which the mutant departs 

 from the parent, as described above, are of a nature that would 

 equip the^ new form for living under more arid conditions than 

 the parent, although the actual endurance of rubrinervis to 

 decreased supply of moisture was not tested. So far as this 

 single observation goes then, it is to be seen that the new char- 

 acters of mutants are harmonious in their adaptive relations. 



(Enotliera rubriiiervis originated in deVries' cultures in 1899, 

 and has also appeared by independent mutations since that time. 

 It has been found to be independent and self-maintenant in 

 competition with the parent form. 



A large number of flower buds in both rnbiincrvis and 

 lamarckiana were pierced by some insect, and the larvae coming 

 from the eggs deposited made great destruction, and also caused 

 the abnormal enlargement of the buds and capsules, which failed 

 to perfect seeds. 



De Vries has continued to find the recurrence of some of the 

 mutants in the successive crops of seedlings of (Enothera 

 lamarckiana indicative of the fact that the mutating period of 

 the parent has not yet been passed. No departures from the 

 parent type were found among the individuals which have come 

 into bloom up to this time in the New York Botanical Garden. 



The leaves of the seedlings of ffi. lamarckiana are easily dis- 

 tinguishable from those of lata, nanella, and rubrinervis even in 

 . the earlier stages, although not so easily separable from some of 

 the other forms such as brevistylis and leptocarpa according to 

 deVries. The earliest leaves were ovate, or round-ovate with 

 rounded apices, or sometimes slightly pointed. These leaves as 

 well as those formed at the age of five months were distinctly 

 petiolate but with the laminae relatively narrower. Adult basal 



