VI PREFACE. 



compelled to discontinue the proper compilation-work just when the last part 

 of the Index Filicum appeared, the remainder of my term of office to be spared 

 for revising, comparing and classifying the various genera and species. There- 

 fore no diagnoses published after January 1st, 1907 are to be found in this 

 work, except those which can be inserted while printing, but as a matter of 

 fact I have not been able to do much more than enumerating as synonyms 

 the new names given to well-known species in consequence of changed 

 conceptions. 



I regret that owing to the want of several books in the Buitenzorg Library 

 I am not in a position lo give diagnoses of some few species of ferns, a lack 

 however which may be considered of but little importance seeing the ferns 

 in question belong to species which are rather rare. Nevertheless I intend to 

 procure their descriptions and publish them later on in an appendix or other 

 supplementary work, together with the other new species that have still been 

 discovered since the date above quoted. 



In giving the diagnoses of the various species I have endeavoured to stick 

 to facts only and to avoid any speculative opinion even when my conception 

 or errors in other authors' work may have tempted me to alter specific na- 

 mes. Of course I do not claim completeness or entire correctness and shall 

 be pleased to have the no doubt many errors and omissions pointed out to me 

 in order to correct them in a supplement. 



As to the limitation and the nomenclature of the genera and species I 

 have chiefly followed the Index Filicum, which with a few exceptions agrees 

 with DiELs' fern-system in Englbr k Prantl's Die nalurlichen Pflanzenfamilien, 

 Vol. I, part 4. In both works however a natural system has been adopted, 

 but as the object of this book is determination only, I have deemed it more 

 practical to adopt for my purpose an artificial arrangemei t. Consequently 

 some clashing between system and arrangement could not be avoided, the 

 same as some few modifications in Christensen's limitation of the genera. 

 So, for instance, I have kept the truly indusiate ferns separate from those which 

 have no indusium or only a spurious one. Accordingly my arrangement is of 

 no systematic value, but only a guide to those studying Malayan Pterido- 

 logy. Therefore I have quoted under each species the name given in the In- 

 dex Filicum wherever I followed my own conception. Where I, for conve- 

 nience' sake, refer to Diels, in Engl. & Prantl, Nat. Pfl.Fam., I*, one should 

 bear in mind that Diels' fern-system is meant, for the articles on the Hy- 

 menophyllaceae are written by Sadebeck and those on the Marattiaceae and 

 Ophioglossaceae by Bitter. 



