568 CATALOGUES. 



(In the seventh edition of the London Catalogue, which was 

 published after the first edition of Topographical Botany, the 

 numbers prefixed to the species were changed, and were raised 

 from 1428 to 1665.) 



4 Topographical Botany ' is adapted to the Sixth Edition 

 of the London Catalogue, as before explained, both in nomen- 

 clature and numeration with some few discrepancies ; and the 

 cited lists are made on the same or earlier editions. But while 

 alluding to the nos. connected with the specific names an old 

 custom of botanical books revived there for its special useful- 

 ness I wish to make record of the advantages derived by 

 myself from those nos. Being used throughout my own books, 

 they give a very ready reference from one book to another. I 

 can find a species more readily and rapidly through the 

 nos. than through order and genus. This is the case, whether 

 it is wished to turn from one book to another, from books to 

 herbarium, or from herbarium to books. Indeed, it may be 

 literal truth to say, that ' Topographical Botany ' would never 

 have been written, never got to by me, if the specific names 

 of the London Catalogue had been unnumbered. 



If rightly used, they vastly facilitate exchanges and dis- 

 tribution of specimens. Ex. c/r. The one-time active Secretary 

 of the Botanical Society of London, the late Mr. George Dennes, 

 really knew but little of botany ; he never was able to name a 

 plant from book description. Yet, through aid of the nos. to 

 the specific names in the London Catalogue, he found it suffi- 

 ciently easy to look' out, or assist in looking out, the desiderata 

 of members. Using the nos. he and I together have looked 

 out upwards of a score of desiderata lists on a Christmas-day 

 morning, and some of them not at all short lists. At its best 

 days the London Society mustered about two hundred members ; 

 and the main annual distributions were usually got through in 

 December or January, while done by the Secretary (much tied 

 by his professional duties) and myself. I wish particularly to 

 record that circumstance, while writing of the uses of the 



