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The potato was introduced to Europe from the 
mountainous parts of South America, about the 
middle of the 16th century ; and it has not now 
been grown in the gardens of Great Britain above 
187 years, nor, to any considerable extent, in our 
fields above 92 years. During the whole period 
of its cultivation it has been treated with the 
greatest care ; yet it was, for a long time, so de- 
cidedly exotic as to refuse to mature its seeds ; 
and even yet, in some unfavourable situations, 
particularly in the Highlands, it sometimes suffers 
general and utter destruction by one night’s early 
frost. Acclimatation has already done much for 
the potato by working out many earlier varieties, 
and by training the later sorts to mature their 
seeds, and to resist the action of moderate frosts ; 
but it will probably do yet much more for it by 
such frequent, careful, and scientific sowings, as 
will not only yield valuable new varieties, but 
produce comparatively hardy plants, capable of 
_ offering a sturdy resistance to early winter.— 
The dahlia was introduced from Mexico to Spain 
in 1787, but reached Paris only in 1802, and did 
| not come into general cultivation till several 
years later ; and yet it has already passed from 
habits of excessive tenderness, and of very late 
flowering, to those of semi-hardiness, and of a 
comparative degree of earliness. It was at first 
raised only in the hothouse ; it was with diffi- 
culty transferred to the open border ; it not very 
long ago refused to bloom in the open air earlier 
than about the middle of October ; and now it 
is very nearly as hardy as the potato,—it is cul- 
tivated and preserved by closely similar methods 
to the potato,—it sometimes, when treated almost 
exactly as the potato, blooms freely in the open 
air in Scotland from about the 8th of September 
| to about the 24th of November,—and it has alto- 
gether undergone so great acclimatation as al- 
ready to seem quite capable of being raised in the 
| fields for food.—The aracacha, one of the most 
useful vegetables of South America, is in some 
respects a more interesting object of both the 
physiologist’s and the farmer’s attention than the 
dahlia, or even the potato ; and, though at pre- 
| sent conflicting with the difficulties of our cli- 
mate, it has, for some time, been justly obtaining 
a large portion of observation and care. See 
ARACACHA, / 
The hemp of New Zealand, Phormium tenax,— 
s0 much more productive of fibre than our own 
hemp or flax, and capable of being manufactured 
into the strongest cordage used in the navy,—has 
succeeded, in a few specimen instances, in the 
gardens of Scotland, and grows healthily in the 
fields throughout the east and the south of Ire- 
land, and may possibly become so acclimatated as 
to yield a suitable and remunerating crop on the 
farms of Great Britain——The Zea mays or Indian 
corn, which affords an excellent provender for all 
live stock, and in times of scarcity has been highly 
prized by the human population, makes itself per- 
fectly at home on the poor sands of Norfolk and 
Suffolk, or on any hot burning lands in the south 
of England, and may probably accommodate i:- 
self to many of the lighter kinds of soils through- 
out the north of England and the south of Scot- 
land.—Tobacco has overcome all reluctance to 
flourish and seed in our gardens ; and, if per- 
mitted by law to be generally grown, might, for 
a short time, be cultivated with vast profit by the | 
farmer.—The Tetragonia expansa, or New Zea- | 
land spinage, was introduced in 1772, and treated | 
for some time as a greenhouse plant, but nowit | 
is as hardy as the nasturtium, keeps its ground | 
from year to year wherever it has been sown, and, 
in some spots in the south of England, has even 
become quite a weed. 
The splendid annual Coreopsis tinctorta, a na- 
tive of the West Indies, is now quite hardy in 
most of our gardens, and perpetuates itself by 
seeds which resist the winter on the spot, and | 
germinate vigorously in spring.—The universal 
favourite mignonette, Reseda odorata, was first 
brought from Africa in 1752, and was for some | 
time cultivated in the hothouse; but it is now 
perfectly acclimatated, and matures its seeds in | 
the open ground.—Our superb greenhouse plant, 
Canna Indica, or Indian shot, has become so com- 
pletely familiar with the climate of Guernsey, as 
to scatter there its seeds every year, and even 
become a troublesome weed in the gardens. But 
the beautiful flowering plants which not very 
long ago were cultivated only in our conserva- 
tories, our greenhouses, and our hothouses, and 
which now withstand all our ordinary frosts, and 
thrive and bloom in the open air, are too many 
to bear enumeration. “Thus,” remarks Dr. Mac- 
Culloch, “ we see everywhere flourishing in the 
borders the most luxuriant plants of heliotrope, | 
fuschia, Verbena triphylla, geraniums, and numer- 
ous others, replacing the wretched starved speci- 
mens formerly nursed with the greatest anxiety 
in the greenhouses.” Numbers of these plants, in- 
deed, had their constitutional habits been pro- | 
perly known, might probably have, from the mo- 
ment of their introduction, been committed to 
the open ground ; but the greater number seem, 
beyond all reasonable doubt, to have undergone 
a real acclimatation,—while a few have been ac- 
climatated to the wonderful extent of a revolu- 
tion in their habits or total change in their con- 
stitution. “ It remains, however, to be proved 
much more clearly than yet has been done,” says 
Dr. MacCulloch, “ what it is precisely by which 
the hardiness of plants is regulated, or how it is 
influenced. It is easy to make use of general 
terms, but they will not satisfy a philosophical 
mind. The effect of frost can unquestionably be 
understood in a general way; yet the tender 
greenhouse plants of England, which are hardy 
in Guernsey, are not killed by the frosts, in which 
that island is not wanting, nor by the cold east- 
erly winds, which prevail there with considerable 
duration and severity. They have always sur- 
vived those attacks; and sometimes, with the 
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