18 INTRODUCTION. 



In this catalogue the descriptions of the different species given 

 in the text are taken from specimens I have personally examined ; 

 a list is appended at the end of each germs of such as are not repre- 

 sented in the collections to which I have had access, and in these 

 cases the definitions are copied from the books in which they are 

 described. I am far from supposing that my work is free from 

 inaccuracy, but every species of which I have given the characters 

 can be examined, either in bulk or as a mounted object, in the 

 British Museum collection. The specimens I have supplied to 

 supplement the collection are indicated in the following pages 

 under each species by the letters L:B.M. 



The rules which govern the nomenclature of species, laid down 

 by Alph. de Candolle, " Laws of Botanical Nomenclature" (1868), 

 and adopted by botanists, require that the first authentic specific 

 name published under the genus in which the species now stands 

 shall take precedence of all others. Compliance with this direction 

 has occasioned considerable alteration of the names given in 

 Rostafinski's Monograph, in which work a severe attention to 

 this important principle has not been observed. I am greatly 

 indebted to Mr. Carruthers, who, in addition to other valuable 

 assistance, has traced the history of each species in the volumes 

 of the British Museum Library, and made the necessary corrections. 



I offer my grateful acknowledgments to those through whose 

 courtesy I have been enabled to study the various herbarium 

 specimens that have come under my notice ; to the Director of 

 the Royal Gardens at Kew for giving me special facilities for 

 investigating the collection under his care, which includes 

 Berkeley's precious series, containing a great number of original 

 types from India, New Zealand, and America that supplied 

 Rostafinski with a large part of the material introduced into 

 the Appendix to his Monograph. These types are to a large 

 extent duplicated in Broome's and Ravenel's collections in the 

 British Museum. To Professor Bayley Balfour I return my 

 thanks for much friendly assistance and for the opportunity of 

 inspecting the specimens in the Royal Herbarium at Edinburgh, 

 including Greville's collection and an almost complete set of 

 type examples supplied by the late Professor de Bary ; to Professor 

 van Tieghem for the inspection of the collection of the Paris 

 Museum ; to Professor A. Blytt for an opportunity of examining 

 the most important types in the Museum at Christiania ; to 

 Dr. Boerlage for giving me access to the Leyden collections ; and 

 especially to Graf zu Solms-Laubach for the privilege afforded me 

 of inspecting de Bary's invaluable collection at Strassburg, con-- 

 tairiing a large proportion of the type specimens referred to by 

 Rostafinski in his original Monograph ; to Dr. Rex, of Phila- 

 delphia, for a nearly complete series of the species found in the 

 United States of America, now represented in the British Museum 

 collection, and for the communication of his views on a group to 

 which he has devoted many years of careful research. I am also 

 grateful to my friend Professor Farlow for many valuable speci- 



