REVIEWS OF NEW PUBLICATIONS. 
51 
Mr. Dickie’s book, as the only one hitherto published relating to any part of 
the North of Scotland, a tract of country less,, known botanically than any other 
portion of Britain, of the same extent. The Northern Flora of the late Dr. Mur¬ 
ray might have supplied a desideratum to British botanists, had the author 
lived to complete it, although the expensive form in which it was published 
would certainly have greatly confined its circulation. 
In the author's remarks concerning the climate of his district, we have a list of 
exotic plants, said to bear the open air at Penzance, in Cornwall; and those 
which will also survive the winters of Aberdeen are distinguished by Italic letters. 
Among these we have Cyclamen Persicum , Azalea Indica , and Myrtus com¬ 
munis —plants which we were not prepared to believe at all likely to bear the 
climate of any part of Scotland, through the year. The Myrtle, indeed, survives 
the winters of England, in situations where they are as cold as the winters of 
Aberdeen ; but they are of shorter duration, whilst the greater heat and longer 
duration of summer enable the Myrtle to bear a lower temperature, by having 
its young wood thoroughly ripened the first season. The two former species are 
greenhouse plants almost throughout England, and we know by experiment that 
the first is very soon injured by frosts less intense than those of Aberdeen. We 
are also told that Buddleia globosa , Fuchsia coccinea , and Hydrangea docolor 
(hortensis ?J U grow without protection during the whole year.” This, we think, 
must be a mistake also. These species are killed to the ground by severe winters 
in England, although their roots will survive and shoot again in spring. Indeed 
it must be a very mild winter in which the Fuchsia is not killed to the ground. 
Possibly the author only meant to say that the roots survived the winter. 
In contradiction to the opinion of Humboldt, adduced by Mr. Dickie, we can 
assure him that the mean temperature of the coldest month is by no means 
the principal point for consideration in determining the influence of winter on the 
vegetation of countries. The minimum of temperature, and the duration of low 
temperatures, or the period during which low temperatures occur at intervals 
are the most essential points. Plants are killed either by low temperatures which 
destroy their vitality, or by a protracted temperature so low as to prevent their 
vegetation, although not low enough to destroy them directly. 
In looking over the list of species, we observed a few names which we should 
not have expected to find without the mark of doubtful nativity attached by Mr. 
Dickie to those species which he supposes to have been introduced by the hand 
of Man. Amongst these are Carum carui, Anchusa sempervirens , Koniga mari - 
tima^ and Melilotus officinalis , which, it would seem, are more likely to have been 
introduced than either Malva moschata or Arum maculatum. The Koniga, 
indeed, our author does not appear to have seen at all; since he gives the British 
Flora as his authority, and Hooker took up the Aberdeen locality from Smith’s 
h 2 
