New YORK 



PREFACE. T,;'^- 



This work, so long announced, is at last completed. Begun 

 three years ago, and at first interrupted by ill-health and 

 other causes, for the last twenty months it has been the subject 

 of continuous labour. 



When I undertook the task of compiling a Guide to the 



Literature of Botany within the compass of a few months, I 



much underrated the magnitude of the task I had set myself 



to do. In common with most people, I believed Pritzel's 



Thesaurus to be practically complete to the end of 1871 ; I 



fancied therefore I had but to select from that storehouse, add 



the titles of such new books as had since appeared, and arrange 



the whole in the order of subjects. The delay in the issue 



'^ of the present work is chiefly due to the unlooked-for heavy 



'^- labour which was found necessary to produce a result which 



J could be deemed satisfactory. 



The history of my work is as follows. Having agreed to 



compile a classified subject-index of short titles, I began by 



extracting from Pritzel such as I thought should be included. 



c-v^' In order to attain the brevity necessary to compress my 



cr> subject within the limits of about two hundred pages, I decided 



I to reject certain classes of works, unless some special reason 



should plead for their retention. Thus I shut out the greatest 



ZD portion of introductory works in foreign languages, theses, 



lectures, inaugural dissertations, works of more medical than 



