ith new matter, and are just as
thick as they are broad. Their vessels are unrecognizable and are hardly
to be distinguished from the mass of the whole; they bear almost no
resemblance to a leaf, and we could easily be misled into regarding them
as special organs. Occasionally, however, they appear as real leaves,
their vessels are capable of the most minute development, their
similarity to the following leaves does not permit us to take them for
special organs, but we recognize them instead to be the first leaves of
the stalk.

"The cotyledons are mostly double, and there is an observation to be
made here which will appear still more important as we proceed--that
is, that the leaves of the first node are often paired, even when the
following leaves of the stalk stand alternately upon it. Here we see an
approximation and a joining of parts which nature afterwards separates
and places at a distance from one another. It is still more remarkable
when the cotyledons take the form of many little leaves gathered about
an axis, and the stalk which grows gradually from their midst produces
the following leaves arranged around it singly in a whorl. This may be
observed very exactly in the growth of the pinus species. Here a corolla
of needles forms at the same time a calyx, and we shall have occasion to
remember the present case in connection with similar phenomena later.

"On the other hand, we observe that even the cotyledons which are most
like a leaf when compared with the following leaves of the stalk are
always more undeveloped or less developed. This is chiefly noticeable
in their margin which is extremely simple and shows few traces of
indentation.

"A few or many of the next following leaves are often already present in
the seed, and lie enclosed between the cotyledons; in their folded state
they are known by the name of plumules. Their form, as compared with the
cotyledons and the following leaves, varies in different plants. Their
chief point of variance, however, from the cotyledons is that they are
flat, delicate, and formed like real leaves generally. They are wholly
green, rest on a visible node, and can no longer deny their relationship
to the following leaves of the stalk, to which, however, they are
usually still inferior, in so far as that their margin is not completely
developed.

"The further development, however, goes on ceaselessly in the leaf, from
node to node; its midrib is elongated, and more or le