150 



Atavism. 



Plantago lanccolafa ra///c^a. therefore, produces a pro- 

 portion of about one-half atavistic individuals every year. 



The variability in the fig- 

 ures given is at least in ]:>art 

 dependent on external in- 

 fluences (nutrition and selec- 

 tion). Closer examination 

 of the individual years proves 

 the truth of this. In 1892 I 

 had 48 plants in flower ; nine 

 of these plants produced split 

 leaves and pitchers at the 

 time when they were Ijeing 

 transplanted, about three 

 weeks after the seed had 

 been sown, and seemed espe- 

 cially desirable on this ac- 

 count. In the summer they 

 turned out to be all rainosa- 

 plants with richly branched 

 spikes. They were cultivated 

 the following year also ; and 

 the sixth generation was 

 raised partly from their seed 

 and partly from the seed har- 

 vested in 1892 from two 

 other seed-parents. From 

 the latter were raised 103 

 plants which flowered, of 

 which 50% were atavists, 

 this proportion being nearly 

 the same for the two seed-parents. In order to investi- 

 gate this, the seeds of the individual seed-parents were, 



Fig. 26. Plantago lanccolafa 

 ramosa. A whole plant. 



