PREFACE. 



HE want of a systematic, illustrated work on the Flora of the 

 United States has long been felt. Some time ago the author 

 of the present volumes seriously entertained a project for such an under- 

 taking, and even went so far as to issue a prospectus. But the diffi- 

 culties in the way of the enterprise seemed so formidable that it was 

 thought prudent to abandon it. The difficulties alluded to can readily 

 be perceived. A glance at the vast extent of our country, with its 

 widely differing conditions of soil, climate, and position, is sufficient to 

 convince even the most superficial observer that the task of describing 

 and illustrating its Flora is one which might well cause even the most 

 courageous of botanists to hold aloof. To complete such a work in the 

 lifetime of one man would be impossible, and this consideration was one 

 of the main reasons which determined the author to abandon his project. 

 In this determination he was strengthened by another consideration, 

 which, although of an entirely different nature, seemed to be quite as 

 potent as the first. A purely scientific and systematic treatise on the 

 Flora of the United States, in the sense in which such a work would l^e 

 understood by the botanist, must necessarily be limited to a small 

 circle of readers, and even in this small circle there would be but few 

 who would care to subscribe to a work, the end of which they might 

 never live to see. While, therefore, such an undertaking was clearly an 

 impossibility from the author's point of view, it was equally evident that 

 no publisher could be found ready to invest in it. 



Under these circumstances, the fact that a work on " The Native 

 Flowers and Ferns of the United States " is offered to the public 

 may need a few words of explanation. 



The plan of the present work differs totally from that of the one 



