INTRODUCTION. 5 
Parr III, which will form our next division, and that, indeed, 
which will comprise by far the greater part of the Work, will be 
the history and description of the different species and vari- 
eties of trees and shrubs, whether native or indigenous, useful 
or ornamental, at present cultivated in Britain. 
We shall add to the perfectly hardy species the names, and 
short descriptive paragraphs, of some ligneous plants, which have 
been found by cultivators to be half-hardy in the climate of Lon- 
don; and of others, which, from their native countries and habits, 
we think not unlikely to prove so. We make this addition to 
the Arboretum et Fruticetum Britannicum for two purposes: 
in the first place, because, by trying species from all countries in 
the open air, some hitherto kept in hot-houses or green-houses 
may be found quite hardy; such having been the case with 
Kérria japonica, Cydénia japonica, Hydrangea Horténsza, 
Aiicuba japonica, and a number of others. We may add, also, 
that, though the nature of a species cannot be so far altered as 
to fit an inhabitant of a very hot climate for a cold one, yet that 
the habits of individuals admit of considerable variation, and 
that some plants of warm climates are found to adapt them- 
selves much more readily to cold climates than others. Thus, 
the common passion flower, according to Dr. Walker, when 
first introduced into the Edinburgh Botanic Garden, lost its 
leaves during winter ; but, in the course of afew years, the same 
plant retained the greater part of them at that season. The 
same author relates that plants of the common yew, sent from 
Paris to Stockholm to plant certain designs by Le Notre, laid 
out there for the king of Sweden, all died, though the yew is 
a native of the latter country, as well as of France. 
Every gardener must have observed that the common weeds 
which have sprung up in pots, in hot-beds or in hot-houses, when 
these pots happen to be set out in the open air during winter or 
spring are killed, or have their leaves injured ; whilst the same 
species, which have sprung up in the open ground, are growing 
around them in a flourishing condition. 
The obvious conclusions from these facts are, that the habits 
of plants admit of a certain degree of change with regard to the 
climate which they will bear ; that the degree in which this power 
exists in any plant is only to be ascertained by experiment ; 
and that the only mode of ning these experiments is, by trying 
in the open air plants usually kept under glass. There is reason 
to believe, from trials already made, that many of the trees and 
shrubs of Australia, and particularly those of New Zealand and 
Van Diemen’s Land, will ultimately become so habituated to the 
climate of London, as to live through the winter against a wall, 
with scarcely any protection. 
*B 4 
