ON THE STRUGGLE FOR EXISTENCE AMONGST PLANTS. 133 
adduce two. One is the Salicorma Arabica , a plant never 
found in its natural state, except in most saline situations, but 
which has flourished for years in the Succulent blouse at Kew, 
in a pot full of common soil, to which no salt has ever been 
added ; the other is the tea plant, which luxuriates in the hot 
humid valleys of Assam, where the thermometer ranges between 
70° and 85°, and the atmosphere is so perennially humid, 
that watches are said to be destroyed after a few months of 
wear ; and it is no less at home in North-Western India, where 
the summers are as hot and cloudless as any in the world, and the 
winters very cold. I may add, that the tea plant has survived 
the intense cold of this last January, at Kew, on the same wall 
where many hardy and half-hardy plants have been killed. 
It is, further, a great mistake to suppose that the native vegeta- 
tion of a country suffers little and very exceptionally by abnormal 
seasons. The most conspicuous instance of the contrary that 
ever fell under my observation, was the destruction of the 
gigantic gum-tree ( Eucalyptus ) forests, in the central districts 
of Tasmania, which occurred, if I remember right, about the 
year 1837. In 1840 I rode over many square miles of country, 
through stupendous forests, in which every tree was, to all ap- 
pearance, absolutely lifeless. The district was totally uninha- 
bited, consisting of low mountain ranges, 2,000 feet above the 
sea, separating marshy tracts interspersed with broad fresh-water 
lakes. The trees, much like the great gaunt elms in Kensing- 
ton Gardens during winter, but much larger, were in countless 
multitudes, 80 to 180 feet high, close-set, and 10 to 20 feet in 
girth ; their weird and ghostly aspect being heightened by the 
fact of most being charred for a considerable distance up the 
trunk, the effects of the native practice of firing the grass in 
summer during the kangaroo hunting season ; and by the bark 
above, hanging from their trunks in streaming shreds, that 
waved dismally in the wind ; for the species was the stringy- 
bark gum, that sheds its bark after this fashion. And not only 
had the gum-trees suffered, the hardier LepiosjpermuWt (tea-tree 
bush), and many others, were killed, some to the ground, and 
some altogether; so that though my journey was in spring, and 
the weather was delightful, the aspect of the vegetation was 
desolate in the extreme. 
In such climates as our own, similar devastations are un- 
known, and though we know that our island was once covered 
with other timber than now clothes it, we have every reason to 
suppose that the change was slow, and the effect either of a 
gradually altered climate, or of the immigration of trees equally 
well or better suited to the conditions of the soil and climate, but 
which had not previously had the opportunity of contesting the 
; ground with the ruling monarchs of the forest. 
