NOTE ON RANGE OF SPECIES. 



The first attempt in recent years to enumerate all of the North 

 American trees (north of the Mexican boundary), with a description of 

 their range and habitat, was made by Prof. C. S. Sargent, and the cat- 

 alogue was published in a bulky volume (IX) of the Tenth Census 

 (1884). The rapid increase of knowledge of American trees since then, 

 however, has made many additions necessary, both as to newly discov- 

 ered species and as to a better understanding of the range of many of 

 those new or little known and also of the well-known species. The 

 elaborate Silva of North America, which Professor Sargent has now 

 nearly completed as a sequel and amplification, with botanical features, 

 etc., of the Tenth Census catalogue, will be the most complete work 

 issued, but from its high price it must unfortunately remain inaccessible 

 to many. 



Aside from these two works our best information concerning the 

 number of species and range of North American trees is to be found 

 chiefly in such regional works on botany as Gray's Manual of Botany 

 of the Northern States, Synoptical Flora of North America (unfinished), 

 Chapman's Flora of the Southern States, Coulter's Manual of Rocky 

 Mountain Botany and Botany of Western Texas, and the Botany of 

 California, by Sereno Watson and other collaborators $ also, recently, 

 the Illustrated Flora of the United States and Canada, by Britton and 

 Brown. Other sources of information are found in the modest and 

 often little known State and county catalogues of plants issued by local 

 botanists, together with various articles scattered through American 

 and foreign scientific journals and proceedings of scientific societies. 



Moreover, the army of professional and amateur botanists engaged 

 in botanical research are yearly bringing to light new facts, which are 

 constantly enlarging our understanding of the geographical distribu- 

 tion of trees and other plants. But our knowledge of the range of tree 

 species alone, especially since so vast a territory, with nearly 500 dif- 

 ferent species, has to be compassed, must long remain a variable quan- 

 tity; and the sum total of facts concerning the geographical range of 

 any of our trees must necessarily be an expression of the united 

 efforts of all working botanists; for the unaided diligence of one 

 man's lifetime could never carry his search and study into all of 

 uature's hiding places for even trees alone. The geographical range 

 notes presented in this volume are, therefore, drawn from all the reli- 

 able botanical publications available, supplemented by new facts per- 

 sonally gathered in recent field work. 



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