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THE OEIGIX OE OUR KITCHEX GARDEX PLAXTS. 
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vation^ and the permanence of some varieties or races. They 
also ^ive ns instructive lessons in the economv of veo-etahle life. 
The Turnip {Brassica campestris) . — This plamt is found wild 
in many parts of England_, by the sides of rivers_, ditches^ and 
marshes_, but is probably only an introduced plant. It grows 
spontaneously all over Europe^ from the Baltic to the Caucasus. 
The wild form has hispid^ lyrate root-leaves_, those of the stem 
are smooth amplexicaule or stem-clasping*. The flowers are 
yellow ; the pod cylindric. The turnip^ like the cabbage^ has 
produced several varieties^ the result of long cultivation_, as 
for example the common cultivated species of tinmip {B. G. 
var. L.)^ and the Swedish turnip (B. G. var. Eutabaga) , 
the root of which is yellowish and sub-globose. This last 
variety^ v/hich is the most valuable to the British farmer_, has 
long been grown in Sweden and Germany^ and was probably 
knovv^n to the ancients. It was first cultivated in England in 
1781, having been brought over originally from Gottenberg. 
Besides these there is another valuable variety {B. G. var. 
oleifera, D. C.), which is largely cultivated in France and 
other European countries for the oil contained in its seeds, 
which, under the name of Colza oil, is used for lamps, giving 
a very brilliant light. The idea of cultivating these plants for 
the oil contained in their seeds could only originate in those 
countries where the olive was not introduced or yielded un- 
certain crops. Colza oil has been used for more than two 
centuries in the north of France, and its use probably dates 
back to a still more ancient period. The Greeks and Romans, 
the Celts and Germans cultivated the turnip ; its original 
country is doubtful on account of the facility with which it 
becomes naturalized outside of cultivated ground. M. Fries 
says that Brassica campestris and Brassica rapa grow spon- 
taneously in the Scandinavian peninsula, and within the last few 
years the explorations of the French naturalist, M. Ledebow, in 
northern and eastern Europe, have shown that both these plants 
are spontaneous through the whole of Russia and Siberia. 
The Horseradish {GocJdearia Armoracea, G.). — This is the 
last of the crucifers whose natural history we shall discuss. It 
is cultivated for its root, the merits of which are well-known 
in connection with the Roast Beef of Old England. We 
shall not occupy the time of our readers with a botanical de- 
scription of this well-known plant, the cultivation of which is 
of undoubted antiquity, as it was used in the time of Pliny, 
the Roman historian. When planted in gardens it is very 
difficult to eradicate, as the rhizome is furnished with many 
eyes, each of which will give rise to a new plant. The horse- 
radish is very frequently found growing outside of cultivated 
ground, on the banks of rivers, and in most situations, but it 
