SENSITIVE PLANT. 
296 
this motion, of which the cause still remains to be 
discovered, the plant appears to be sensible to the 
impression not only of bodies immediately applied 
to it, but likewise to the influence of the surround- 
ing elements, &c. Thus sudden degrees of heat, or 
cold, the vapour of boiling water, the fumes arising 
from sulphur, the odour of volatile liquors ; or, in 
short, any thing that deranges the nerves of animals, 
will also affect the sensitive plant. 
There are other species of this genus that possess 
the same faculty in different degrees ; the subject 
of our present consideration is the common sensi- 
tive plant, and was originally introduced into our 
gardens from Brasil, and other parts of South Ame- 
rica. The stem is cylindrical, and of a green 
or purplish colour, with two spines at the base of 
each leaf, besides a few others scattered about the 
branches. The leaves are pinnatifid, supported on 
long footstalks, and each pinnule is furnished with 
fifteen or twenty pair of oblong, narrow, and; shin- 
ing leaflets. From the base of the leafstalks pro- 
ceed the peduncles, each of which supports a bunch 
of very small white or flesh-coloured flowers. The 
seed-vessels are united in packets of twelve or fifteen 
each : they are edged with minute spines, and each 
husk contains three little seeds. 
As soon as the evening approaches, the sensitive 
plant begins to lower its leaves, till at length they 
rest upon the stem : but it is not this property 
which is so remarkable; as, far from being confined 
to the mimosa, it is common to many plants, espe- 
