MORE ABOUT LEAVES.
"WHO wants to study in vacation?"
The speaker was Mr. Browne's nephew; he sat upon a stump in the woods
not far from the pretty booth where Mrs. Browne awaited the coming of
her class. He kicked his heels against the half-decayed bark which,
giving way under the repeated kicks and falling to the ground, was
picked up by the youngest of the trio of Brownes and stored away for
the gypsy fire which he proposed to build after a while.
"And botany too! I don't care a flip about that stuff; I wanted to go
fishing; it's lots more fun."
"But we can't fish all the time; and mother makes botany real
interesting. The other day we had to talk about roots, because that
comes first, and we thought it would be terribly stupid; but it wasn't!
We liked it first-rate, and we know quite a number of things now about
roots, so come on, Charlie."
"Bother!" Charlie very slowly descended from his perch, and followed
the others with a scowl on his rather handsome face. Mrs. Browne
welcomed him with a smile, not appearing to notice his surly mood.
"We will talk a little about leaves to-day," she said. "There are two
principal sorts of leaves; now I want you to look at these which I
have brought and see if you can find out the difference between them."
She handed the children some leaves of the lily of the valley and the
tulip, with others from a maple tree near by.
"The shape is different," said one.
"Yes; but that is not what I mean; try again."
"They are not the same color?"
"Try again."
"The maple leaf is divided off by three little ridges spreading apart
from the stem," said Ella.
"And how about the others?" asked Mrs. Browne.
"There's only one running through the middle."
"And there's a lot of little cross-marks, or threads, or whatever you
call them, in the maple; and in the lily of the valley, and in the
tulip they run all one way."
"Ah! now you are coming at it. The two great divisions of leaves of
which I just spoke are characterized by these threads, or, as we call
them, veins. The maple belongs to the netted-veined leaves, and the
others to the parallel-veined. You remember that at our first talk
we learned about seed-leaves? Can any of you tell what we called the
seed-leaves?"
"Cotyledons," said all three in a breath.
"Right. Well, the parallel-veined leaves belong to the sort of
plants which have only one seed-leaf or cotyledon, and we call them
monocotyledonous plants; and the netted-veined leaves belong to and
distinguish those with two cotyledons, and are called dicotyledonous
plants. Now notice that a leaf has three parts: a blade, the broad
thin part, a petiole, or, as you would call it, the stem-stalk, which
supports it; and, as you see in these quince leaves, there is also
a pair of small leaf-like appendages which are called stipules. All
leaves do not have these, and some have no petioles. In such cases we
say the leaf is sessile, and sessile means sitting; and we shall find
the word used in regard to other parts of the plant as we go on in
our study. This quince, and also the apple leaf, have one large vein
running through the middle as if the petiole were extended to the tip
or apex of the leaf. This sends off branches, and these in turn break
into smaller ones until the leaf is all over network. It is tilled in
with a green pulp and covered with a thin skin called the epidermis."
"Why, we had that word in physiology," exclaimed one of the listeners.
"It means the same as cuticle or outside skin."
"Exactly; so you see we have in the blade the fibrous framework or
skeleton, the pulpy filling, and the transparent covering."
Charlie had been listlessly fingering a leaf, seemingly not interested
in the talk, but at this moment he started up, exclaiming, "I know
how to make skeleton leaves! You just put the leaf into some kind of
acid—I have forgotten the name, that eats out the pulp and leaves the
framework—sister Anna has a whole lot of them."
"Yes; and if we had one here we could see the method of veining
very plainly. In the parallel-veined leaves all the larger ribs run
lengthwise, and there are no branching veins which you can see plainly,
only very small vein-lets. Now just a glance at the leaves of a plant
or tree will tell you to which of two great divisions the plant or tree
belongs."
"I did not suppose there could be so much to say about leaves," said
Ella, turning her leaf over and looking curiously at it.
Mrs. Browne smiled. "We have only just begun to examine them. We might
find things enough about them to fill a great many morning hours. We
might talk about the shapes. We have: ovate and lanceolate, oblong and
orbicular and a great many more you might find it hard to remember.
Then the margins. Some are entire, that is, even, not notched, and
others—but look for yourselves and find out the differences."
"This willow is notched, and so is the elm leaf," said Charley, growing
interested.
"But are they alike?"
"No; the elm has what I should call double notches."
"Exactly; one is serrate or saw-toothed, the other double serrate."
"And here is a leaf that is scalloped."
"You will find many forms if you take notice, and each has a name."
"I shall be looking at leaves after this," said one.
"You must try to find out all you can about them. Notice the
arrangement upon the stem. Some are opposite, like the maple, others
like the rose are alternate; now here is a pansy—excuse me for picking
to pieces this pretty bouquet which you gave me, but it is in the
interest of Science. The pansy or violet has alternate leaves with
stipules, while the sweet pea has a compound leaf; but I know you are
anxious to get to flowers, and we will take them up next time, only we
ought to talk a little about the uses of leaves. You may find as many
uses as you can before we come here for another talk."
"Didn't you like it?" asked one of the Brownes as they stopped on the
way home to enjoy the top rail of the fence.
"It wasn't so bad as I thought it would be," replied Charlie. "I never
should have suspected that there was so much talk to be made over a
leaf."
"Nor I," echoed all the others.