PREFACE TO PART XI. 



In Part XI, AMERICAN WOODS, we resume the study of the species of 

 the Atlantic and Central States. 



We regret considerable delay in its appearance, owing mainly to demands 

 upon the author's time for the preparation and issue of the companion work, 

 HANDBOOK OF TREES. 



That was the outgrowth of plans announced with Parts IX and X, 

 AMERICAN WOODS, but carried out on somewhat different lines. It was 

 found impracticable to issue TREE STUDIES iu fasicles, as then intended, 

 and, instead, it was decided to issue a Handbook, photo-descriptive of 

 characteristic barks, leaves, fruits, winter branch lets, etc., of the various 

 trees and indicate their distributions by the use of small individual maps, 

 with photo-micrographs to show wood structures of at least one species of 

 each genus. 



To keep such a work within reasonable dimensions it was decided to limit 

 it to the species found north of the latitude of the northern boundary of 

 North Carolina and east of the Rocky Mountains, with the hope of supple- 

 menting it later if possible with similar handbooks of the trees of the Pacific 

 slope and of the Southern States. 



The one covering the trees of the Northern States and Canada was finally 

 brought out, but to make it complete required much more time and field 

 work than was anticipated, owing to off years, when a species would not 

 bear flowers or fruit, the shortness of the period when suitable specimens for 

 photographing could be procured, etc. 



While the prosecution of this work delayed the issue of AMERICAN WOODS, 

 Part XI, it furnished an opportunity for the further study of our eastern 

 trees, which we feel has enhanced its value. 



Deviating somewhat from the plan of previous Parts of the series the 

 keys based upon flowers and fruits have been dispensed with in Part XI, 

 and a considerably elaborated key based upon the leaves is included. This 

 i? designed to cover all of the generally accepted species of native and natu- 

 ralized trees of northern Fnitod States and Canada, and is based upon what 



