VI PREFACE. 



Acknowledgments are here rendered to those who have aided 

 in the preparation of this edition. Especially we would men- 

 tion Dr. Sereno Watson, of the Botanic Gardens at Cambridge 

 for access to numerous specimens ; Professor Daniel C. Eaton, 

 of Yale, for elucidating the synonymy of Aspidium patitlum ; 

 and most of all, Mr. George E. Davenport for very many kindly 

 suggestions, specimens, and courtesies extending through a 

 series of years. 



SYRACUSE UNIVERSITY, 

 Feb. 18, 1888. 



