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THE FERN BULLETIN 



tention that "Acrostichchum" is only "Aspidium" 

 with reduced fertile pinnae appears to me to be better 

 established than ever. Is this a step in advance in 

 the development or a degeneration ? The example of 

 Dryopteris canescens where the incontestable deforma- 

 tion of the pinnae both fertile and sterile, is accom- 

 panied by the acrostichoid formation as to the sorif- 

 erous parts, appears to me to point strongly to the lat- 

 ter ; that is to say, an aberration and weakening of 

 the type, which one can scarcely call only teratologi- 

 cal, because the influences that have caused the changes 

 are unknown." An excellent example of this may be 

 seen in our common Christmas fern, whose specific 

 name, Acrostichoides, was derived from the- fact that 

 it closely resembles an Acrostichuiu. While such 

 ferns point unmistakably to an alliance of Nephrodium 

 with Acrostichum, other forms as clearly connect it 

 through Phegopteris with Poly podium. 



INDEX TO RECENT LITERATURE. 



Readers are requested to call our attention to any 

 errors in, or omissions from, this list. 



Binford, R. The Development of the Sporangia in 

 Lygodium, illust. Botanical Gazette, S. 1907. 



Clute, W. N.. Naming the Ferns without a Book, 

 illust. American Botanist, Je. 1906. 



Dobbin, F. A Fern Community. American Botanist, 

 Ap 1906. 



Life, H. C. Effect of Light upon the Germination 

 of Spores and the Gaiuetophyte of Ferns, illust. 

 18th Report of Missouri Botanical Garden, 1907. — 



