The _arum Dracunculus_ is one of the most curious of that wonderful
series of carnivorous plants which at the present time are engaging
the closest scrutiny of naturalists. It is a true trap in one
sense--inasmuch as it captures the victim which ventures near it; but
it relies on little or no mechanical means for securing its prey, but
stupefies the living insect by its odor. The flower is horn-shaped,
about 11 inches in length, with an opening some 5 inches in diameter.
The color within is a dull dark violet, while the interior of the
spathe is lined with black, hooked bristles, the whole appearance
of the flower being thoroughly repulsive. The illustrations herewith
presented, Figs. 1 and 2, represent it at one third its natural
size, Fig. 2 showing a section of the flower. It is not certain what
attracts the insects, which are usually of the species known as the
meat fly and the common house fly. They do not seem to seek for the
small quantity of nectar concealed, and yet they cluster about the
fatal opening, as if drawn by some overpowering fascination. Overcome
by lethargy, they fall inert upon the flower, are lightly held by the
bristles, and finally die asphyxiated by the carbonic acid which the
plant disengages in large quantities during its inflorescence. Strange
as is the action of the _arum_, the method whereby the _mentzelia_
takes its prey is even more wonderful. To illustrate on a magnified
scale, let the reader imagine a surface thickly covered with strong
iron posts, on the sides of which are numerous keen barbs pointing
downward. Then between these posts, suppose that jars overflowing with
honey are placed. An elephant, let it be imagined, attracted by the
profusion of sweetness, inserts his trunk between the posts and
finds easy access to the honey. But while he can force his proboscis
downward past the barbs turned in that direction, when he attempts to
withdraw it he finds the keen points catch in the flesh, and render
it impossible to do so. A terrible struggle follows, the unfortunate
animal twisting and writhing in every direction, until finally by
an Herculean effort the head is torn from the body, and the latter
becomes digested by some potent gastric juice, exuding from the
colossal organism of which the trap forms but a portion. Of course
this is vastly exaggerated, and it would puzzle an elephant to pull
his own head off; but if for the post studded trap, we substitute the
surface of a flower, and if we replace the elephant by a fly, we shall
have conceived an accurate picture of what takes place in the peculiar
receptacle with which Nature has provided the _mentzelia ornata_.
This is very beautifully shown in Fig. 3; and at A, in same figure,
is represented the barbed bristles grasping the highly magnified
proboscis of the fly. Between the barbed bristles are mushroom-shaped
projections, from the summits of which a viscous nectar exudes. This
is the honey bait which induces the insect to insert his trunk between
the fatal barbs. There is still another plant, _physianthus albens_,
which captures butterflies by grasping the proboscis. The construction
of the flower is quite complicated, so that the insects are compelled
to insert their trunks through a narrow and winding passage in order
to reach the nectar. The organ then necessarily comes in contact with
an adhesive substance, which prevents its removal.
The _Gronovia scandens_, Fig. 4, is another plant trap, which catches
no flies nor possesses any such wonderfully adapted devices as the
plants already described. It simply has its branches covered with
double barbed bristles of great strength which attach themselves to
anything brought in contact with them. The bristles are strong enough
to hold lizards, as represented by our engraving, the points inserting
themselves in the interstices of the scaly covering of the reptile.
Of course the lizard thus held starves to death, and small birds
often follow a like fate. We are indebted to _La Nature_ for the
illustrations.
[Illustration: Figs. 1 and 2.--ARUM DRACUNCULUS.]
[Illustration: Fig. 3.--MENTZELIA.]
[Illustration: Fig. 4.--GRONOVIA SCANDENS.]
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