1016 



added. Hudson united it with tlie other Poas, under the name of 

 Poa loliacea ; and Glyceria being a section of the genus Poa, the 

 plant in question is called G. loliacea in the London Catalogue. In 

 the Edinburgh Catalogue, further subdivisions of the old genus Poa 

 were adopted, and this plant was associated with other species of Poa 

 or Glyceria {S7?iith) under the name of Sclerochloa. Thus, putting 

 the two Catalogues in contrast, the increase of generic names was 

 here made by the Edinburgh, not by the London Catalogue. 



Without entering more into explanations relative to species singly, 

 it may fairly be assumed, that the proper test of a publication like the 

 London Catalogue, is to be found in its adaptation to the end for which 

 it is published. This Catalogue is expressly stated to have " been 

 prepared chiefly with the object of giving increased facility in the 

 exchanges of specimens, regularly carried on between the Botanical 

 Society of London and its individual members." Some probability 

 that it is adapted to such object, is implied in the fact of its distinc- 

 tive peculiarities having been suggested by a botanist, who has had 

 many years' experience in the exchange of specimens, both at home 

 and abroad, and who was the first to bring such printed lists into use 

 for the purposes of these exchanges, many years ago. The most im- 

 portant of the peculiarities which distinguish the London Catalogue 

 from all its predecessors, is the attempt to show the comparative scar- 

 city of each species, by means of the local Floras; and it is supposed 

 that few persons will deny some usefulness in this innovation. 



Secondly ; a distinction is made between species which probably 

 can be obtained for exchange, and species which probably cannot be 

 obtained ; and he must be a botanist of small experience who has not 

 found the inconvenience of a list which includes (without distinction) 

 the names of many species of which it is impossible to obtain British 

 specimens. Foreign botanists almost invariably ask for those species, 

 and are disappointed when they receive a parcel without any of them. 



Thirdly, the native and naturalized species are also distinguished ; 

 the usefulness of such a distinction being practically admitted by the 

 authors of our descriptive Floras, who latterly have done the same. 

 Useful though this be, every good botanist knows well that the dis- 

 tinction cannot always be made with confidence. Thus, Babington 

 describes Chelidonium majus and Impatiens Noli-me-tangere as na- 

 tive species ; yet Hooker marks the latter as a non -indigenous plant, 

 and Henslow marks the former " possibly introduced by the agency 

 of man." If Mr. Sidebotham can accomplish a task, only attempted 

 by Smith, Hooker, Henslow, Babington, Watson and others, by all 



