viii PREFACE T PART XI. 



we consider typical forms of leaves such as we see on mature trees and 

 not abnormally vigorous shoots. It would be an almost hopeless task to 

 frame a key covering all unusual forms of leaves and keep within reasonable 

 space, but one covering typical forms has seemed possible and has been here 

 attempted. In its use the above limitation must be kept in mind, and what 

 \vould be called average typical leaves selected for application of the key. 

 With them, if possible, the fruits should be observed, as in framing the key 

 fruits have been more or less included of necessity or for confirming other 

 characters. 



In the preparation of the key the use of technical terms has been avoided 

 where others would do as well, but they could not be wholly dispensed with 

 without sacrifice of definiteness, and that would be disastrous to the purposes 

 of the undertaking. 



For more convenient use in the field this key is being issued in small 

 book form (4x6 in. in size of page) with glossary and an attractive photo- 

 graphic picture in colors of an isolated elm tree in both summer and winter 

 conditions, as frontispiece. 



For favor? which were of material assistance in the preparation of 

 AMERICAN WOODS, Part XI, the author wishes to express sincere thanks 

 to Prof. William Trelease, Dr. N. M. Glatfelter, Mr. C. D. Beadle, Mr. 

 T. B. Ha, oison, Mr. W. T. Davis, Mr. G. W. Letterman, Mr. Enos A. Mills, 

 Mr. B. \\. King and Mr. J. C. Teas. 



As an item of news of unusual interest to the author of AMERICAN WOODS, 

 he is tempted to mention here the fact that since the appearance of Part X 

 he has been awarded, through the Franklin Institute of Philadelphia, Pa., 

 the special Elliott Cresson gold -medal on account of its production. Inas- 

 much as this action was entirely on the initiative of the Institute, whose 

 rulings are looked upon as authoritative, it is a very gratifying testimonial, 

 after the great amount of labor and money that have been expended in 

 bringing out the work. 



The wood-specimens for Part XII, AMERICAN WOODS, are already in 

 hand and that volume is intended to be issued before the close of the present 

 year. 



LOWVILI.E. X. Y.. May 31, 1910. 



