PREFACE. XIX 



something like twenty publications bearing date of 1881, the 

 wbole of whicli were actually sent out before the close of 

 1880, and, with two exceptions, all were actually in my 

 hands last year. I have included no work which has been 

 published since 'New Year's Day of this year; my volume is 

 therefore practically complete to the end of 1880, although 

 probably many foreign and colonial publications might right- 

 fully claim admittance, which have been shut out on account 

 of distance and the time of transit. 



So far we have considered the case of independent works ; 

 of course the literature of any subject is largely made up of 

 articles in Journals and Societies' publications, which in many 

 cases form the most important contributions to special subjects. 

 But it was clearly impossible for me to include all magazine 

 articles in this volume ; I have therefore given a list of the 

 principal sources of information on this head, and there must 

 leave it, however much I may regret to pass by in silence 

 such important essays as Dr. (now Sir) J. D. Hooker's Distri- 

 bution of Arctic Plants, in the Linnean Society's Transactions, 

 or the various contributions on the flora of Rodriguez and 

 Kerguelen, in the Philosophical Transactions. 



After selection of the books themselves came the arrange- 

 ment under subjects. The task was one of abundant difficulty, 

 so much so that I would never again attempt a catalogue 

 which was primarily a classified list. Were I again to engage 

 in any extensive bibliographical labour I would steadily 

 adhere to the practice of ranging the works under an alpha- 

 betical sequence of authors' names; this course minimizes 

 trouble, and chances of error as to names and dates. As a 

 consequence of my systematic arrangement, I found it ex- 

 tremely difficult to refer to my previous collections, thus 



