2 BULLETIN 207, U. S. DEPARTMENT OF AGEICULTUEE. 



are not found anywhere in this country. Such species, however, are 

 not considered in the present bulletin. 



So far as possible the use of technical descriptive terms has been 

 avoided, and only such distinguishing characters (color, texture, etc.) 

 are defined as can not be shown clearly in a black and white drawing. 

 The illustrations represent foliage, fruits, seeds, and other important 

 parts of the trees in their natural size, so that the element of size, so 

 often distinctive, as well as the form in the specimen studied, can be 

 easily compared with the drawing. To insure accuracy in details 

 practically all of the illustrations are line drawings of photographs. 



The maps showing the geographical distribution * of the different 

 species are photographic reductions of the large folio sheets upon 

 which the distribution data were originally platted, thus affording a 

 more accurate outline of range than is apparent from the small size 

 of the map. These data include all the published and unpublished 

 information now available in the Forest Service. 2 The greater part 

 comprises field notes and unrecorded observations and reports of 

 Forest Service officials who, in the exploration and administration of 

 the National Forests, have special opportunities for gathering such 



Additional information was obtained from field notes accom- 

 panying specimens preserved in the forest herbaria of the Forest 

 Service and the National Museum, Washington, D. C, while through 

 the courtesy of officials in charge similar information was gathered 

 from the Arnold Arboretum, Jamaica Plain, Mass., the Field Museum 

 of Natural History, Chicago, 111., and the University of Nebraska, 

 Lincoln, Nebr. Field notes, forest photographs, and specimens col- 

 lected by members of the Bureau of the Biological Survey have also 

 contributed new and valuable range data. 3 



1 Only the botanical range is shown, it being impracticable to combine with this the commercial range 

 of timber-producing species, the supplies of which are constantly reduced by lumbering operations. 



2 The Mexican range of cypresses and junipers is so imperfectly known at present that but few authentic 

 locations are given for them in that region. These locations are shown by small circles of solid color. 

 Further provisional range of these trees in Mexico is indicated by short parallel lines and is based only 

 on reports which have not been verified. 



3 Grateful acknowledgment is made in this connection to Dr. C. Hart Merriam, formerly chief of the 

 Bureau of Biological Survey; to Dr. H. W. Henshaw, present chief of that bureau, and to Dr. A. K. Fisher, 

 Chief of the Division of Economic Ornithology; also to Messrs. Vernon Bailey and H. C. Oberholser, mem- 

 bers of the same bureau. To Prof. Charles S. Sargent, director of the Arnold Arboretum, and to Prof. J. G. 

 Jack of the same institution, the author desires especially to acknowledge his hearty appreciation for the 

 loan of herbarium specimens and other helpful courtesies. The writer's cordial thanks are here expressed 

 to Dr. Charles E. Bessey (now deceased), of the University of Nebraska, and to Dr. C F. Millspaugh, of the 

 Field Museum of Natural History, for the privilege of compiling range data from the herbaria in their 

 departments. For helpful information regarding junipers in Texas acknowledgment is made to Prof. 

 William L. Bray, now of the University of Syracuse, N. Y. Acknowledgment is due also to Mary C 

 Gannett for the compilation and preliminary mapping of a part of the range data, and to W. H. Lamb 

 and Georgia E. Wharton, of the Section of Forest Distribution, who revised and completed this compi- 

 lation and prepared final copies of the distribution maps. Finally, the writer wishes to express his 

 grateful appreciation of the assistance received in various ways from Forest officers and other members of 

 the Forest Service. 



