branch from those which enter the tentacles on each side. Their glands
are much elongated, and lie embedded on the upper surface of the
pedicel, instead of standing at the apex. In other respects they do not
differ essentially from the oval ones, and in one specimen I found
every possible transition between the two states. In another specimen
there were no long-headed glands. These marginal tentacles lose their
irritability earlier than the others; and when a stimulus is applied to
the centre of the leaf, they are excited into action after the others.
When cut-off leaves are immersed in water, they alone often become
inflected.
The purple fluid or granular matter which fills the cells of the glands
differs to a certain extent from that within the cells of the pedicels.
For when a leaf is placed in hot water or in certain acids, the glands
become quite white and opaque, whereas [page 8] the cells of the
pedicels are rendered of a bright red, with the exception of those
close beneath the glands. These latter cells lose their pale red tint;
and the green matter which they, as well as the basal cells, contain,
becomes of a brighter green. The petioles bear many multicellular
hairs, some of which near the blade are surmounted, according to
Nitschke, by a few rounded cells, which appear to be rudimentary
glands. Both surfaces of the leaf, the pedicels of the tentacles,
especially the lower sides of the outer ones, and the petioles, are
studded with minute papillae (hairs or trichomes), having a conical
basis, and bearing on their summits two, and occasionally three or even
four, rounded cells, containing much protoplasm. These papillae are
generally colourless, but sometimes include a little purple fluid. They
vary in development, and graduate, as Nitschke* states, and as I
repeatedly observed, into the long multicellular hairs. The latter, as
well as the papillae, are probably rudiments of formerly existing
tentacles.
I may here add, in order not to recur to the papillae, that they do not
secrete, but are easily permeated by various fluids: thus when living
or dead leaves are immersed in a solution of one part of chloride of
gold, or of nitrate of silver, to 437 of water, they are quickly
blackened, and the discoloration soon spreads to the surrounding
tissue. The long multicellular hairs are not so quickly affected. After
a leaf had been left in a weak infusion of raw meat for 10 hours, the
cells of the papillae had evidently absorbed animal matter, for instead
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