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THE AMERICAN NATURALIST [Vol. XLIX 



a most unexpected segregation into three marked types, 

 forma typica, reproducing the parental form, and two 

 dwarf types, mut. semialta and mut. debilis, so named 

 because of their resemblance to the two classes of dwarfs 

 which de Vries 2 obtained from (E. nanella X (E. biennis. 

 Mut. semialta is about half as tall as f. typica and has a 



very dense and showy inflorescence in which the fruits 

 and flowers are very little smaller than in the parent 

 form. The leaves, however, are decidedly reduced. Mut. 

 debilis is more variable in size than mut. semialta, but 

 averages about half as high as the latter. Its fruits and 

 flowers are somewhat reduced, but by no means propor- 

 tionately to the size of the plant. The leaves, on the 

 contrary, are much more reduced than those of mut. 

 semialta. The inflorescence is not as dense, but often 

 longer. 



The unlooked-for occurrence of these types in the F 3 

 of 1913 led to the duplication in 1914 of both the F 2 and 

 F 3 generations from seeds which had been left over from 

 former years. In 100 additional F 2 plants of the mutant 



2"Gruppenweise Artbildung, " pp. 241-244. 



