CURIOSITIES OF VEGETATION. 
539 
CURIOSITIES OF VEGETATION. 
THE SENSITIVE PLANT. 
The plant to which this name was ori- 
ginally applied, is not that which is commonly 
grown as such in the gardens ; that is the 
Mimosa pudica, or humble plant, a species 
nearly allied, indeed, to the preceding, but 
differing in having the leaves of a different 
composition, the flower-heads of a different 
colour, and the whole habit more decumbent 
and spreading. This species, 31. pudica, has 
in a greater degree the same sensitive pro- 
perties in the leaves as the original sensitive 
plant, 31. sensitiva, and several other species, 
and has, for some reason or other, become the 
more common. tM. sensitiva is represented in 
the accompanying engraving. 
It is an annual, with weak slender woody 
stems, sometimes acquiring eight feet in 
height, scattered over here and there with 
recurved prickle?, and producing branches 
from the axils of the lower leaves. The 
branches are furnished with alternate distant 
leaves of very singular composition ; they are 
what is called conjugato-pinnate, that is to 
say, the leaf branches out into two corre- 
sponding arms, each of which is pinnate. 
These arms, or pinnas, have each two pairs of 
pinna?, or in other words are bijugate ; the 
lowest pair is very unequal in size, but the 
upper pair of equal size, and in these re- 
spects the two pinnae are alike : the leaf, 
therefore, consists of six perfect full-sized 
leaflets, and two very diminutive ones. The 
form of the leaves is what is called subdimi- 
diate-ovate, or approaching to half-ovate, or 
one-sided, the lower being much more deve- 
loped than the other side. The flowers form 
little balls of threads, on longish stalks, from 
the axils of the upper leaves ; those on the 
uppermost part of the plant being often pro- 
duced two from each axil ; the colour is very 
pale purple, that is, white just tinted. It is 
a native of South America, and was first 
introduced into England in the year 1648. 
The other, the commonly-grown species, 
31. pudica, is decumbent in habit, and has 
the leaves digitato-pinnate, or spread out like 
the fingers of the hand ; the divisions being 
pinnate, and bearing numerous small crowded 
oblong leaflets. The flower-heads are lilac 
coloured, and grow from the axils of the 
leaves. This kind is common in the West 
India Islands, whence it was introduced about 
1638. This is the more sensitive of the two, 
which probably accounts for its commonness 
in a cultivated state. 
