HEREDITY, AND THE ORIGIN OP SPECIES — MACDOUGAL. 511 



During the last four years a partial duplication and an extension 

 of these experiments has been carried on in New York. It seems 

 unnecessary at this late date to go into the detail of the mutations of 

 Lamarck's evening primrose, especially since the phenomena exhibited 



Pig. 2. — Oenothera ruhrinervis, one of the mutants of 0. Lamarckiana. A, B, and C, leaves 

 from rosette ; D, leaf from middle of flowering stem ; F, flower with petals removed : 

 G, petal. 



by them are also to be seen in many other species. By way of illus- 

 tration it need only be said that this plant, as originally observed by 

 De Vries, was found to give from two to five plantlets in every hun- 

 dred which were widely divergent from the type, and could, upon 



