204 
EFFECTS OF SITUATION AND EXPOSURE, &c. 
of our seasons compared with that of their own, but entirely from the 
changeableness of the former. In Siberia the winter sets in at once, 
and the surface of the ground is soon covered with snow; every 
vegetable becomes instantly torpid, and in this state remains in perfect 
safety till the return of spring, or rather summer, as there is scarcely 
any spring season in that northern clime,—no intermission of mildness to 
excite, and frosts to destroy the tender plants, as is so often experienced 
in this country. Mr. Anderson, the curator of the Chelsea Botanic 
Garden, has, in his collection of the genus Iris, several from Siberia, 
which require particular management to see them in beauty. Soon 
as a bright day in February warms the ground, forth come these 
humble gems of the north ; and which, without some protection, would 
be withered by the first frosty night, or first frosty wind that blows. 
The changeableness of our spring weather is, in fact, the greatest bar 
to our possessing very many plants, which, to have at all, must be 
guarded in some kind of building erected for the purpose. Our want 
of success in attempting to naturalise some exotic shrubs and trees, 
however, may have happened not so much from the constitutional 
delicacy of the plants themselves, as to the injudicious manner, perhapSj 
in which the trial has been made. Exposed situations on the north 
side of a hill, and on poor and dry, rather than on rich and moist soil, 
is certainly the most eligible station for making a trial of the constitu¬ 
tion of a foreign plant. Here it would not be excited into too early 
growth by the early sun of the day or of the season, nor would the 
aspect induce precocious growth. Its growth would be slower, but its 
shoots would be firmer in texture, and consequently better able to resist 
the destructive effects of frozen sap. 
We cannot conclude these observations without first alluding: to the 
ideas entertained about the acclimatation of exotic plants. The notion 
is founded on the supposition that, as animals have a tendency to 
accommodate themselves to foreign climates, or to the changes of 
temperature of their own native place, so plants may in like manner be 
susceptible of physical changes which would enable them to bear 
great diversity of climatal temperature; but from all experience on 
this point it appears, from many tropical annuals long cultivated 
in Britain, that they have not perceptibly advanced in hardihood since 
the first day of their introduction. Such are the runner kidney-bean 
(which by the bye is a perennial) ; the potato and cucumber among 
culinary vegetables ; the China aster and balsam among flowers; and the 
melon among fruits. All these have been perpetuated by seeds 
produced in this country ever since their first introduction ; but without 
gaining any additional protective habit against frost. We may, there- 
