iv Preface 



in a single species, the account is preceded by a synoptical descrip- 

 tion of the fern-plant in its mature stages. 



The distribution of the species is mostly quoted from Mr. 

 William R. Maxon's "List of the Ferns and Fern Allies of North 

 America, North of Mexico, with Principal Synonomy and Dis- 

 tribution." * Most of the spore characters cited are quoted from 

 Prof. D. C. Eaton's "Ferns of North America." With these 

 exceptions, and a few others noted as they occur, all descriptions 

 have been drawn from or verified by specimens examined by 

 myself. I have personally collected in the field or raised from 

 spores nearly all the young leaves figured and described. 



The illustrations of leaves, throughout the book, excepting 

 where otherwise stated, are life size. 



The nomenclature is in accordance with the American code. 

 Sufficient synonomy is cited to include the more important 

 synonyms. 



I wish to render acknowledgments to all who by their cour- 

 tesy have aided in any way the preparation of this book. To 

 Dr. Lucien M. Underwood I am under obligations for kindly 

 examining the synoptical descriptions of the species, for valuable 

 suggestions, and for very many kindnesses and courtesies, includ- 

 ing the privilege of access to important books and specimens. 

 I wish to express likewise my indebtedness to Mr. George E. 

 Davenport, for kindness in connection with numerous speci- 

 mens. To Dr. Henry F. Walker I am indebted in many ways, 

 which it gives me much pleasure to acknowledge. Miss Kath- 

 erine Foot also should be especially mentioned. Mrs. N. L. 

 Britton and members of the American Fern Society have kindly 

 furnished me with certain notes and specimens. 



*Proc. U. S. Nat. Mus. 23: 619-651. 1901. 



