8 



tures on Elementary Forestry at the Pennsylvania State Forest 

 Academy. 



Part II is essentially a manual of Pennsylvania trees. It com- 

 prises a discussion on the identification of trees and a description of 

 families, genera, and species, with accompanying keys. The descrip- 

 tive material and keys are the outgrowth of typewritten outline 

 notes prepared by the author and used for the past six years in con- 

 nection with a course in dendrology given at the Pennsylvania State 

 Forest Academy. Each species is described under about 14 headings. 

 No special originality is claimed for the characteristics given under 

 these headings. It is natural to expect that the descriptive mater- 

 ial should correspond with that found in other texts. The author 

 is glad to acknowledge his indebtedness to the many books of refer- 

 ence which were frequently consulted to verify observations and to 

 make the description clear and complete. The range of the species 

 and the weight per cubic foot of their wood (air dry) have been 

 drawn chiefly from Sargent's "The Silva of North America." The 

 distribution in Pennsylvania was worked out in co-operation with 

 the foresters connected with the Department of Forestry and a few 

 others interested in the distribution of trees. Porter's "Flora of 

 Pennsylvania" aided considerably in determining the distribution. 

 Our present knowledge of the distribution of the different species 

 in the State is by no means complete. Special efforts are being put 

 forth to ascertain it more accurately. Future publications will con- 

 tain the results of the present and prospective surveys covering the 

 distribution of our trees. Any additions, suggestions, or corrections 

 will be gladly received. 



The scientific names found in this bulletin are those used by the 

 Department of Forestry, which follows the usage of the seventh edi- 

 tion of Gray's New Manual of Botany. Shifting of individual 

 plates from their proper systematic position was necessary in a few 

 cases in order to place two companion plates on opposite sides of the 

 same sheet. 



The photographic illustrations, 103 in number, are all original 

 by the author, except Figs. 57 and 63 supplied by W. Gardiner Oonk- 

 lin; Fig. 22 supplied by Guy Carleton Hawkins; Figs. 21 and 35 

 supplied by B. J. Gutknecht, and Figs. 1, 3, 4, 10, and 12 supplied 

 by the Pennsylvania Department of Forestry. 



The drawings have been made by Miss Margaretta Washington, of 

 Philadelphia, either from specimens supplied by the author or re- 

 drawn and adapted from Sargent's "The Silva of North America" by 

 special permission of the publisher, Houghton Mifflin Company. In 

 making some of the drawings Schneider's "Dendrologische Winter- 

 studien" and some of the reports of the Missouri Botanical Garden 

 were consulted. 



