Oenothera Laevifolia. 



311 



sing occasional crumples on its leaves and sometimes 

 whole leaves covered with them. Or again the smooth- 

 ness of the leaves gradually de- 

 creases from the top of the stem 

 downwards. It even happens 

 sometimes that it is impossible to 

 draw a sharp line of demarcation 

 between Lamarckiana and the 

 smooth leaved plants, or to cal- 

 culate the percentage of the lat- 

 ter. 



When it was possible to allow 

 not merely the main stem of the 

 plant to grow (which was all I 

 could do as a rule, through lack 

 of space) but also the lateral 

 branches which spring from the 

 axils of the radical leaves it was 

 found that the laevifolia-charac- 

 ters were better developed in the 

 leaves of the branches than in 

 those of the main stem. In such 

 cases these were often useful in 

 identifying the plant. 



O. laevifolia has obviously in- 

 herited the occasional crumples 

 which it possesses, from its parent 

 species; they can be regarded as 

 rudimentary or atavistic charac- 

 ters.^ Closer study will probably 

 prove such relics to be much commoner in nature than 



Fig. 58. Radical leaf of 

 a rosette of O. lata, 

 viewed from the dor- 

 sal side, to show the 

 numerous unevennesses 

 (crumples) on its sur- 

 face. 



*Like the stalked leaves of the young plants of O. nanella. See 

 § 18 and the tables in § 27 of this part. 



