BOTANICAL SOCIETY OF LONDON. 
11 
duration in different latitudes may also be ascertained from 
the same source, with many other particulars respecting the 
geographical distribution of species, their abundance or their 
scarcity in different localities, their various appearances in 
different altitudes in open or in shady places, their preference 
for some soils, or their total indifference to this change. 
These, and many other interesting particulars, can only be 
communicated by resident Botanists. 
One of the desiderata which could easily be supplied by 
the Botanical Society of London, is a Flora of its environs. 
During a residence of several years in the Metropolitan 
Counties of Surrey, Kent, Middlesex, and Essex, the author 
of this communication was engaged in collecting for this 
purpose, and he is satisfied that the amount of vascular 
plants growing within twenty-five or thirty miles of London 
is underrated at one thousand ; and as there are no Alpine 
plants in this tract, and only a few maritime species, this 
may justly be considered the richest district in the kingdom, 
(for we have no local Flora containing an equal number) and 
it will repay the most accurate and extensive investigation. 
The number of Phanerogamous species detected, classified, 
and described by myself as growing on Hampstead Heath, 
and in the woods and fields adjoining, within less than two 
miles, was some years ago six hundred and seventy. And 
as it is probable that a few species were overlooked, seven 
hundred may be expected in that quarter. I have more re- 
cently been employed on the Croydon plants, and have al- 
ready entered about nine hundred species growing within 
twelve miles of the town ; and this list, I am assured, is far 
from complete ; if we add to these the plants growing on 
the banks of the river Thames, from Windsor Forest to the 
Isle of Sheppy, with the growth of the chalk hills about 
Maidstone and Rochester, the Chiltern Hundreds, the 
Essex Marshes, Epping Forest, Leith Hill, and the Hog’s 
Back between Dorking and Guildford, we need not be 
afraid of exaggeration in stating them at upwards of one thou- 
sand. From the proportion which the number of species in 
certain families bear to the whole vascular Flora, the plants 
may, in any particular district or country, be estimated— 
For example, in the average of six Floras, viz. : the Edin- 
burgh, the Devon, the Berwick, the Hampstead, the Scotch, 
and English Floras, the number of grasses is to the whole 
number of Phaenogamous plants, described in these Floras, as 
one-eleventh and a half ; or there are eleven and a half times 
