6 PREFACE. 



field. Our knowledge of spores and sporelings is far 

 from complete ; the prothallia of some species have 

 never been seen ; the phenomena of fern hybridization 

 have scarcely been 'touched upon; while the study of 

 the natural variation in species will afford much profita- 

 ble work. There is also the ever delightful occupation 

 of exploring unfamiliar territory and the possibility of 

 thus adding to our knowledge of the distribution of 

 species. The range of each species has been given in 

 accordance with our present information, but it is ex. 

 pected that many will prove to be more widely dispersed 

 and that some now marked rare will ultimately be found 

 to be more abundant. I shall be pleased to receive 

 further information upon these points and will also 

 undertake to identify any ferns that may be sent me 

 provided that good fruiting specimens with rootstock, 

 when possible, be selected for the purpose. 



In the preparation of this volume, I have had the 

 hearty cooperation of American fern students and take 

 this opportunity to express my indebtedness to them. 

 My thanks are especially due to Mr. William R. Maxon 

 for data regarding the range of many species, to Mr. 

 George E. Davenport for verifying the nomenclature 

 of the Check-List, to Mr. B. D. Gilbert for carefully 

 reading the proof-sheets, and to Prof. L. M. Underwood 

 for much valued information. 



WILLARD N. CLUTE. 

 Binghamton, N. Y. 

 April 12, 1901. 



