168 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



speaking of introductions into Europe, he alludes to Oenothera biennis, 

 " the evening primrose, and many others could be given. They have 

 not developed any special European features after their introduction " 

 (p. 695). But elsewhere he tells us that this plant has mutated into 

 a form he calls cruciata (p. 587). 



I think, therefore, that one may agree with Mr. Clements, who 

 observes that " the evidence from the mutants of Onagra (as to constancy) 

 is not : convincing. Indeed, where there can be no question of the 

 occurrence of mutation (i.e. sporting) in plants, a fact known for many 

 years, the facts so far brought forward in support of the 1 Mutation 

 theory ' fall far short of proving the high value of mutability for the 

 origin of species." * 



In conclusion, I would call attention to a misrepresentation of Darwin, 

 from whom De Vries claims support which Darwin repudiated. With 

 regard to Evolution he says : " Darwin has recognised two possibilities. 

 One means of change lies in the sudden and spontaneous production of 

 new forms from the old stock. The other is the origin by means of 

 natural selection." "What Darwin maintained was that extreme forms 

 such as what are understood as "sports" have not been a source of 

 evolution. 



Darwin's alternative to natural selection was the direct action of the 

 new conditions of life by which new forms arise "without the aid of 

 natural selection." t De Vries passes this over in silence. But it is now 

 being prominently insisted upon by Ecologists who cannot fail to see it 

 in action in Nature everywhere. 



* Research Methods in Ecology, by F. E. Clements, Ph.D., 1905. 

 f A?iimals and Plants under Domestication, vol. ii. p. 271, &c. 



