vi INTRODUCTION. VOL. I. 



relegated to synonymy, while others have been recognized in this edition by brief notes in 

 order to call attention to them and to indicate the necessity for their further study, in order 

 to ascertain their true status. Similar notes have been entered relative to a few species of 

 which the occurrence within the area has become known to the authors during the prepara- 

 tion and composition of the work, which has covered a period of nearly four years, a course 

 which has been taken in order to supersede the need of an Appendix. 



A few species illustrated in the first edition have been omitted, except by the entry of 

 notes upon them, in the second, for reasons explained by such notes, mostly because they 

 have been ascertained to be undistinguishable specifically from others. 



The enterprise, projected by Judge Brown, and maintained and supervised by him 

 throughout, has been prosecuted for the past twenty-two years. Its execution has been 

 mainly the work of Dr. Britton. The text, founded upon a careful examination of living or 

 herbarium specimens, has been chiefly prepared by him, with the assistance, however, of 

 specialists in a few groups who have contributed the descriptions for certain families as 

 stated in the footnotes. The figures also have been drawn by artists under his immediate 

 supervision; except those of most of the grasses, drawn for the first edition by Mr. Holm, 

 under the eye of Prof. Scribner, and those in the other families contributed by specialists 

 who have supervised them ; while the work in all its parts has been carefully revised by both 

 authors. The keys to the genera and species, based upon a few distinctice characters, will, 

 it is believed, greatly facilitate the determinations. 



In preparing a new work of this character, the authors have felt that there should be no 

 hesitation in adopting the matured results of recent botanical studies here and in Europe, so 

 as to bring the work fully abreast of the knowledge and scientific conceptions of the time, 

 and make it answer present needs. Although this involves changes in systematic order, in 

 nomenclature, and in the division of families and genera, such as may seem to some to be 

 too radical, no doubt is entertained that time will fully justify these changes in the judgment 

 of all, and demonstrate that the permanent advantages to Botanical Science will far out- 

 weigh any temporary inconveniences, as has been already so fully shown in Ornithology and 

 other zoological sciences. 



The first edition was issued in three volumes, published consecutively in 1896, 1897 and 

 1898. The second edition is issued in three volumes simultaneously published. 



Area. 



The area of the work extends from the Atlantic Ocean westward, in general, to the 

 I02d Meridian, a little beyond that of Gray's Manual, so as to include the whole of the State 

 of Kansas ; and northward from the parallel of the southern boundary of Virginia and Ken- 

 tucky to the northern limits of Labrador and Manitoba. For convenience, the whole of 

 Nebraska has been included, thus permitting the illustration of practically the entire Flora 

 of the northern portion of the Great Plains. Western North and South Dakota are not 

 included. 



The Flora of Canada and the British possessions not being distinguishable by any well 

 marked features from that of the adjacent parts of the United States, and not embracing 

 more than about 400 additional species, it was deemed best to include this more northern 

 territory, in order to present a manual of the whole Flora of the northeastern part of the 

 continent, with the exception of that of Greenland and the Arctic Circle, which is much the 

 same on both continents ; nearly all the Arctic plants are, however, included, as but very few 

 of them are strictly confined to the Arctic Zone. 



Further botanical exploration will, doubtless, reveal additional species, especially along 

 the southern and western boundaries, and in the north. 



Figures. 



Within the above area there are over 4600 recognized species, more than three times the 

 number in Bentham's Illustrated Handbook of the British Flora. To illustrate all these in a 

 work of moderate size and cost, only parts of each plant could usually be figured, and these 

 mostly below life-size. To exhibit full-page illustrations would have added fourfold to the 

 bulk of the work, and the consequent more limited sales would have necessarily increased 

 the price in a much greater proportion, and thus have thwarted the primary objects, viz., to 



