332 J- Christian Bay. 



historical investigation, even though their compilers may not at all 

 have cared for bibliography as such. It also is recognized that many 

 a slight list of titles appended to a paper on some narrowly limited 

 topic, possess a distinct value as perhaps the only available "biblio- 

 graphy" of that topic. But this kind of material must be selected 

 with great care. Although having clearly in view the principle of 

 selection in this field I cannot hope to satisfy all demands on the 

 part of others, in the inclusion of such special bibliographies. But 

 I hope to have erred mainly on the side of inclusion rather than on 

 that of exclusion, even though some matter must have eluded my 

 search. 



Another class of bibliographies calls for a note of explanation. 

 The history of botany numbers many works of bibliographical im- 

 portance. An experience with the botanical literature of smaller 

 localities shows how valuable, even for purely bibliographic purposes, 

 local historico-botanical treatises may be, especially when more com- 

 prehensive bibliographies for the region in question are lacking. 

 Hence, I have included freely some historical matter both general 

 treatises and local histories of botany. 



It is almost needless to explain that collective reviews : the form 

 of topical bibliography so common and so very useful, have been 

 diligently sought out and noted. 



A number of librarians and botanists in all parts of the world 

 have rendered valuable aid in the preparation of this as in that of 

 my larger work, and I acknowledge this help with gratitude. But 

 my aim has been to quote nothing that I had not seen. Happily, the 

 cases where I must rely upon data supplied by kind colleagues, are 

 hardly two per cent. My successive connection with large and ex- 

 cellent libraries -- the Missouri Botanical Garden, the Library of 

 Congress, the John Crerar Library has been of great advantage 

 to this work. 



It was hoped that Heinrich Romer's great bibliography, left 

 by him in manuscript, afterwards purchased by Henckel von 

 Donnersmarck and lost since the death of Count Henckel, 

 would have been found before the present time. A voluminous corre- 

 spondance with institutions and localities where the manuscript might 

 repose, gave hitherto but a negative result. But my search continues. 



In the final editing of this work, as indeed in the acquirement 

 of what may be termed a definite philosophy of the greater cause 

 that I aim to serve, much valuable suggestion was derived from 

 V. Grundtvig's masterful essay, Gedanken iiber Bibliographic (in 

 Centralblatt fur Bibliothekswesen XX (1903), p. 405444). 



The collations given in detail for some periodicals are inserted 

 both as a matter of information and, secondarily, to emphazise the 



