These plants are so constructed as to attract insects, capture them in
various ways, and feed upon them. Perhaps the best known of the group
is _Venus' Fly-Trap_. The leaves vary from one to six inches long, and
at the extremities are placed two blades, or claspers. On the inner
walls of these claspers are placed six irritable hairs; the slightest
touch from an insect on any one of which is sufficient to bring the
two blades together with such rapidity as to preclude any possibility
of the fly escaping.
[Illustration: LEAVES OF THE FLY-TRAP OPENED AND CLOSED.]
This plant readily discriminates between animal and other matter;
thus, if a small stone or piece of wood be dropped into the trap, it
will instantly close, but as soon as it has found out its mistake--and
it only takes a few minutes--it begins to unfold its trap, and the
piece of wood or stone falls out. On the other hand, should a piece of
beef or a bluebottle fly be placed in it, it will remain firmly closed
until all the matter is absorbed through the leaf. It will then unfold
itself, and is ready for another meal.
[Illustration: AUSTRALIAN PITCHER PLANT.]
Another species is called the _Vegetable Whiskey Shop_, as it captures
its victims by intoxication. The entire shop is shaped after the
manner of a house, with the entrance projecting a little over the rim.
Half-way round the brim of the cavity there are an immense number of
honey glands, which the influence of the sun brings into active
operation. This sweet acts as a lure to passing insects, and they are
sure to alight on the outside edge and tap the nectar.
They, however, remain there but a brief period, as there is something
more substantial inside the cavity in the shape of an intoxicating
liquid, which is distilled by the plant. The way down to this beverage
is straight, as the entrance is paved with innumerable fine hairs, all
pointing to the bottom, and should the fly walk crooked its feet
become entangled in them.
[Illustration: AMERICAN SIDE-SADDLE FLOWER.]
When the fly has had its first sip, it does not stop and fly right
out, as it could do, but it indulges until it comes staggering up and
reaches that portion where the hairs begin; here its progress outward
is stopped, owing to the points of the hairs being placed against it.
The fly is now in a pitiable plight; it attempts to use its wings, but
in doing so only hasten its destruction. It inevitably gets immersed
in the liquid, and dies drunk.
_Australian Pitcher Plant_ is a beautiful little object. Its pitchers
are at the bottom of the principal stem of the plant.
One species distils an intoxicant of its own; but owing to its small
orifice, it excludes the majority of insects, and admits but a select
few. The individual pitchers somewhat resemble an inverted parrot's
bill, with a narrow leaf-like expansion running along the top. The
color is light green, beautifully shaded with crimson. The inside of
the pitcher is divided into three parts: The first, nearest the
entrance, is studded with minute honey glands, and is called the
attractive surface; a little farther down the inside, very minute
hairs are situated with their extremities all pointing to the other
chamber. This is the conducting surface.
[Illustration: THE PITCHER PLANT OF MADAGASCAR.]
Lastly, the small hairs give place to the longer ones, amid which are
placed secreting pores, which give forth the intoxicating nectar. This
is termed the detentive surface. When the pitcher has caught a
sufficient number of insects, the nectar gives place to a substance
which enables the plant more readily to digest its food.
Another variety is the _Mosquito Catcher_. It grows about one foot
high, and the leaves, after reaching a certain height, divide into
long, narrow spathes, covered with hairs, each coated with a bright
gummy substance. This, during sunshine, gives to the plant a most
magnificent appearance. If a plant be placed in a room where
mosquitoes abound, all the troublesome pests will in a brief period be
in its steady embrace.
It is most interesting to watch the method by which it secures its
prey. Immediately the fly alights on the leaf, it may be that only
one of its six legs stick to the sweet, viscid substance at the
extremity of the hairs; but in struggling to free itself, it
invariably touches with its legs or wings the contiguous hairs, and is
immediately fixed.
These little hairs meantime are not idle; they slowly but surely curl
round and draw their victim into the very center of the leaf, thus
bringing it into contact with the very short hairs, which are placed
there in order to facilitate the process of sucking the life-blood
from the body.