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THE FERN BULLETIN 



are also hybrids. In the opinion of the editor of this 

 magazine, the contention that an immense amount of 

 hybridization exists in a group of the wood ferns 

 (Nephrodium) must be set down as not proven. It 

 is true that many forms that do not fit our descrip- 

 tions of the species have been found and it is also true 

 that some of them look as if they might be interme- 

 diate between two species, but if we can read any- 

 thing from the recent literature of hybridization it is 

 clear that the first cross seldom gives individuals inter- 

 mediate between the two parents but that it requires 

 the second generation to bring out the distinctions. 

 The work of crossing ferns is an infinitely more deli- 

 cate operation than crossing flowering plants and, ow- 

 ing to the nature of the plants in question, a genera- 

 tion of so-called hybrids may not be hybrids at all but 

 mere variations. The prothallium may produce new 

 ferns by budding, which avoids crossing at all, and 

 even the best of crossing is largely guess-work due to 

 the fact that prothallia from which one or the other 

 sex-organ has been removed can develop new ones, 

 or the eggs may have been fertilized before the sperms 

 were removed. If we hoped to produce variable ferns, 

 mutilating the gametophyte or prothallium would be 

 one of the first means suggested and it is not to be 

 wondered at that a lot of mutilated prothallia should 

 give some variable plants. We do not insist that the 

 wood-ferns do not hybridize but we venture the opin-, 

 ion that they do not do so as regularly as the descrip- 

 tion of new hybrids in the group would lead one to be- 

 lieve. If the variation in the wood fern is to be 

 ascribed to hybridization, to what shall we attribute 

 similar variation in the grape-ferns? One of the 

 fundamental principles of any kind of organic evolu- 



