the thread-like blade became only on one occasion very slightly bent,
directly beneath the insect. Perhaps this indicates that the blades of
vigorous plants would bend over captured insects, and Dr. Canby informs
me that this is the case; but the movement cannot be strongly
pronounced, as it was not observed by Mrs. Treat.
Drosera binata (or dichotoma).—I am much indebted to Lady
* ‘American Naturalist,’ December 1873, page 705. [page 282]
Dorothy Nevill for a fine plant of this almost gigantic Australian
species, which differs in some interesting points from those previously
described. In this specimen the rush-like footstalks of the leaves were
20 inches in length. The blade bifurcates at its junction with the
footstalk, and twice or thrice afterwards, curling about in an
irregular manner. It is narrow, being only 3/20 of an inch in breadth.
One blade was 7 1/2 inches long, so that the entire leaf, including the
footstalk, was above 27 inches in length. Both surfaces are slightly
hollowed out. The upper surface is covered with tentacles arranged in
alternate rows; those in the middle being short and crowded together,
those towards the margins longer, even twice or thrice as long as the
blade is broad. The glands of the exterior tentacles are of a much
darker red than those of the central ones. The pedicels of all are
green. The apex of the blade is attenuated, and bears very long
tentacles. Mr. Copland informs me that the leaves of a plant which he
kept for some years were generally covered with captured insects before
they withered.
The leaves do not differ in essential points of structure or of
function from those of the previously described species. Bits of meat
or a little saliva placed on the glands of the exterior tentacles
caused well-marked movement in 3 m., and particles of glass acted in 4
m. The tentacles with the latter particles re-expanded after 22 hrs. A
piece of leaf immersed in a few drops of a solution of one part of
carbonate of ammonia to 437 of water had all the glands blackened and
all the tentacles inflected in 5 m. A bit of raw meat, placed on
several glands in the medial furrow, was well clasped in 2 hrs. 10 m.
by the marginal tentacles on both sides. Bits of roast meat and small
flies did not act quite so quickly; and albumen and fibrin still less
quickly. One of the bits of meat excited so much secretion (which is
always acid) that it flowed some way down the medial furrow, causing
the inflection of the tentacles on both sides as far as it extended.
Particles of glass placed on the glands in the medial furrow did not
stimulate them sufficiently for any motor impulse to be sent to the
outer tentacles. In no case was the blade of the leaf, even the
attenuated apex, at all inflected.
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