No. 577] 



MUTATION THEORY OF DE VRIES 



16 



Lawrence and the New England States. I have further 

 examined a large number of species of Oenothera from 

 various parts of the continent and in every instance have 

 found a greater or smaller amount of abortive pollen as a 

 characteristic feature of the anther contents. De Vries 

 in his "Mutationstheorie" describes the abortive condi- 

 tion of about one third of the grains in 0. lamarckiana. 

 This feature has been seized upon with insight by Bate- 

 son, as indicating the hybrid origin of 0. lamarckiana. It 

 is extremely curious that its significance should have 



escaped De Vries and his numerous disciples on this con- 

 tinent. Not only is 0. lamarckiana itself characterized by 

 a large proportion of abortive pollen but its so-called 

 mutants are similarly characterized. In the feebler "ele- 

 mentary species" the pollen is often almost entirely 

 abortive (0. nanella) and this is also generally the situa- 

 tion in 0. lata. It should be further noted in this connec- 

 tion that if 0. lamarckiana is of hybrid origin, the same 

 statement must hold of the other species of (Enothera, 

 since like this much-disputed one. they are similarly char- 

 acterized, so far as they have been studied, by two corre- 

 lated features, namely more or less abortive pollen and the 

 peculiarity of throwing so-called mutants or "elementary 

 species" in cultures. As a consequence of this condition, 



