always do so, and that its occurring under the conditions which 

 I have described shows there is still another cause, lying deeper, 

 which must be searched for before a final conclusion is reached, 

 and that until the facts I have given are explained, the solution 

 still remains an open question. 



These facts do not rest upon my own evidence alone, but are 

 well supported by other testimony. Dr. Torrey himself gives an 

 instance where specimens were found growing on the same root- 

 stock with the normal form. Prof. Eaton, in "Ferns of North 

 America," mentions its occasional occurrence also. Mrs. M. L. 

 Stevens, a member of the Fern Chapter, tells me that the only 

 time she ever found obtusilobata, was on large plants that had 

 not been injured ; and Mrs. P. D. Richards, of the Massachu- 

 setts Horticultural Society, tells me that it was only within a 

 few years that she knew it was more likely to be found in the new 

 mown meadows, and she always found it before on normal plants. 



During the present season I have persistently cut away, in 

 some only partially, and in others all of the sterile fronds from 

 several plants on my own grounds, and also in several patches of 

 plants growing in a convenient woodland, and have so far found 

 but one imperfect specimen on a plant with half the sterile fronds 

 remaining. Within a week I have been over several hundred 

 plants that had been cut down, trampled on, and otherwise injured 

 by the Gypsy Moth Destroyers — destroyers in more sense than 

 one — but I could not find any variation, although there were 

 hundreds of fertile fronds in all stages of development, some of 

 which had clearly developed after the plants had been mutilated. 



Now I do not wish to be understood as questioning the fact 

 that obtusilobata often follows mutilation, because I know from 

 my own experience in collecting it in newly mown meadows that 

 in such cases it certainly does do so, and the cause appears to be 

 so clear that one may almost certainly expect to find specimens 

 in the wake of the scythe ; but it is a little singular, if mutilation 

 is the real cause, that in all of my own efforts to obtain specimens 

 by mutilation I have only partially succeeded once, and I insist, 

 that, inasmuch as mutilation does not account for the facts which 

 I published seventeen years ago, and here restate with additional 

 corroborative testimony, there must be some other cause to be 

 searched for.* 



* This has been still further confirmed by Mrs. Britton, and Rev. James 

 A. Bates, both of whom stated at the meeting of the Fern Chapter, that they 

 had found the form growing on normal plant s. 



