CATALOGUES. 567 



exact character of ■which I do not now recollect. More recently 

 it has become strictly systematic. 



The Botanical Society of London for a time attempted to 

 cary on their exchanges and distribution of specimens by aid of 

 the Edinburgh Catalogue. But its alphabetical arrangement 

 and changed nomenclature being found exceedingly inconvenient 

 for such use of it, I was requested to try whether some other 

 form of Catalogue could not be adopted instead, more convenient 

 in its arrangement for the purpose required. Not unwUlingly 

 I undertook this little, task ; looking forward to the service 

 which such a Catalogue would be calculated to render to myself 

 also, as a ready mode of obtaining Local Lists of plants in a 

 systematic instead of an alphabetical form. 



It will have been seen by those users of this book, who have 

 looked over the list of Catalogues explained, that the greater 

 number of them have been made out by marking copies of the 

 ' London Catalogue of British Plants ' ; also, that the edition 

 used has always been mentioned in the explanation. As before 

 remarked, this gives their successive and approximate dates 

 and it so far suggests a clue to the states or stages of our 

 descriptive botany at the time the local lists were made out. 

 During the thirty-six years, nearly, from the first alphabetical 

 list to the sixth edition of the London Catalogue in 1867, there 

 has been a continued tendency to subdivide old Linnean species 

 into more numerous modern segregates, and the tendency has 

 been increasingly apparent since (say) 1842. The effect of this 

 appears of course in the catalogues of names ; the later the 

 edition of a catalogue used in marking off a local list of plants, 

 the greater the chance for a segregate name to be marked in it 

 and either along with or in lieu of a more aggregate name. The 

 several editions of the London Catalogue are dated thus : — 



1844 edition first. 1857 edition fifth. 



1848 „ second. 1867 „ sixth. 



1850 „ third. 1874 ,, seventh. 



1853 ,, fourth. 



