Oenothera Laevifolia. 



09 



I have often brought Oenothera laevifolia from Hil- 

 versum to Amsterdam, sometimes in the shape of seeds, 

 sometimes by fertihzing castrated flowers of my O. La- 

 viarckiana with laevifolia pollen. From the seeds ripened 

 at Hilversum I obtained in 1888, for example, no more 

 than 2 % laevifolia ; in 

 1895, on the other 

 hand, about 50 %. The 

 former number is ob- 

 viously the result of 

 the rarity of the spe- 

 cies in question at that 

 time, there being little 

 chance of its being fer- 

 tilized by its own pol- 

 len. 



The distinguishing 

 features of this species 

 are to be found partly 

 in the leaves and partly 

 in the flowers. 



The leaves of Oeno- 

 thera Lamarckiana are 

 rather coarse, an effect 

 produced by the numer- 

 ous crumples which dis- 

 tort the areas between 

 the veins and especially 

 those areas which border on the middle region of the 

 principal veins. They are caused by a faulty correla- 

 tion between the growth of the areas and of the veins; 

 either the areas grow too fast, or the veins elongate too 

 slowlv. 



Fig. 56. Oenothera laevifolia. Top of 

 a stem, in flower. 



