III. SEGREGATES anp tHErR NOMENCLATURE. 
In explaining the formula used in the ‘Synopsis of Species,’ 
on pages 79—420, it was intimated that a general commentary 
afterwards would include the Alien plants and * also several 
segregate species, the distribution of which is yet too imperfectly 
ascertained, to allow of the formula being adhered to for them, 
if taken apart from each other.” Great difficulty is experienced 
in the attempt to shew the topographical distribution of that 
miscellaneous group of plants, which ought to include everything 
not already treated in the foregoing ‘Synopsis.’ Brevity is 
absolutely necessary in a single volume which professes to be 
only a Compendium ; while something like sameness of plan is 
needful, to prevent brevity lapsing quite into non-intelligilility. 
Looking to the Segregates in the first place. These may be 
distinguished roughly into three groups. First, those which have 
long been separated in books, more or less clearly, and which 
have thus become passably well known to botanical collectors and 
recorders of localities. Many of this first group have been already 
treated in the Synopsis, because the records of their localities 
were found sufficiently numerous, and in the main also sufficiently 
reliable, to afford the necessary data, when joined with those in 
the Author’s own notes and herbarium, the accumulations of 
many years. Second, there are numerous recent severauces, not 
yet become familiar to botanists who are guided by descriptive 
books in which these recent segregates remain unnoticed, or who 
have not seen such authentic examples as would suffice to render 
the novel species or variety (it matters not which it be called here) 
rf 
