Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1875-09-24
Leaves.
BY PROFESSOR HENRY NJ. sEELY

,e thought. it is originally little fold or e.
lie pansion of the inner bark OF the plant {
% tree. We know that if we cut away ii
- red or russell, the gray or brown outer bar
a OF a twig, we come to a green or true BARI
)f before reaching the wood. 1t is, as | think
L this inner bark looped upon the branch, tha
: forms the leaf 1t is this little fold of inne
;, tissue, 50 simple in its original shape, tha
develops into the myriad forms which Civ
: each tree and shrub and plant form q
5 foliage peculiarly its own this simple organ
! a little fold, transforming itself into tn
$ most complex and manifold forms.
= The essential structure ola leaf is wood
en- frame, braced and iDterlaced and fllet
with moist cell tissue, and over all is stretch
e ed.a film or skin of empty cells. pierced wit.
1 many holes, and often roughened by pro
= jecting hairs.
As the building is boarded up and FILED
, in, 50 is the the leafy frame packed in with
: moist, and then covered with dry cells.
2 1t Is the frame, varying in size and form,
and the cells, increasing or decreasing in
amount, that gives the eyer-changing leaf
Those vary SO much in character. that were
it not possible to follow one modification to
another and trace the change we would
never admit that they sprung from the same
source, and in fact represented the same or
gan.
As we look carefully at it, We shall find
that We may distinguish the complete leaf
into three distinct parts; and these are the
broad lamina or blade which we ordinarily
call the leaf, and then the stalk, which the
bDtanist calls the petiole, but which is some
times abseut, and last; at the insertion of
the stalk or petiole are stipules, two little
projections something like ears in shape.
These last are sometimes wanting.
Now let US look. little more carefully at
the structure of the leaf Beginning down
at the insertion where the leaf stands upon
the branch or stem, we will most often find
this pair Of ear-like appendages or stipules.
Sometimes, however, they do not appear,
and sometimes they fall of 50 soon after the
leaf has unfolded that one must look at the
right time to find them. And in what shape
shall We find them? Sometimes small and
pointed, sometimes rounded, and then again
forming a circle or sheath, then again broad
euing out into wide, leaf-like body, more
| like leaf than all the rest Of the leaf
/ Strange shapes these little organs, these
supuies, sometimes assume and one Of these
/ Is that Of spines, as seen On the young locust
/ tree. and again as tendrils assisting the
weak plant to climb up into the sunlight.
Next look how the leaf Is fastened to the
branch; usually by the broadening of the
base, and not unfreGuently by claSping a.
most around the stem, ike hand clasping
rope. 80 II clings through calm and storm
Now let Us look at the stalk OF the leaf, the
pttiole, that lifts the broader part, the lam
ina or blade, up to the sun. Bat sometimes
there will be no petiole at all, the blade
standing directly upon the stem but usual
ly there Will be peti0le, sometimes short
indeed, then again long and very noticeable.
W G think at first that We may dismiss the
petiole with a word But do We ever think
what gives character to a tree ? First, with
out doubt, it is the general form Of the trunk
and ang.e Of the branches but grace and
beauty come with the form Of the branches,
and especially the smaller branches or spray.
Look al an elm, and then at an oak or bet
ter, compare the little, dropping branches
Of the weeping willow with the upright, |
rigid horSe-chesnut. See one swayiu., in |
the breeze or tossed by the storm. anu the
wrenched and cracked by the powerful wind. |
The rigidity or suppleneSs OF the spray will |
determine the movements Of the tree when I
acted upon by the stronger winds. But |
there are other motions that give each tree |
It's Individuality, and these motions depend |
upon the character OF tie petiole of the leaf. /
If this be short. and section be circular, /
there can scarcely be a graceful movement Of /
the leaf if however this be long, and especI- I
ally if it be hAuenei, then with the least I
breeze every leaf will be in motion. Look /
at the poplar, 1.-The trembling aspen" whose
every leaf is tongue telling OF the zephyr's |
breath, wnen otherwise we would think the |
air wholly still. It's the long, fattened
pe:i0le that permits the blade to sway at
even the passing shadows of breeze.
And if we could follow this matter OF the
petiole, as we cannot now do, we should find |
it passing into new and strange forms, twin
ing ike tendril in the clemAtis, following /
itself in the form Of a Aattened leaf, then tax
ing on other aud almost unacceptable
shapes.
Leaving now the petiole, We pass farther
up and come to the blade, the part we are
accustomed to call the leaf. Looking more
carefully, we see the woody frame run
ming along in nearly parallel lines, as in the
leaf of the corn and lily, or more frequently
as in our trees and shrubs and most of our
garden plants, the frame spreads, sometimes
like the wide-stretched fingers Of hand
sometimes like the vanes Of feather and
these portions Of the frame become smaller,
connecting with each other, and meshing in
to each other like the threads of a net. final
ly escaping from oar observation, because 50
small. If we would find how this meshing
is filed, we must call TO our aid the micro
sope Then we shall see the network Of
woody fbres and duets, filled in with round
cd or angular cells, or the inner ones, filed
with fluid in which are found some wonder
ful grains of waxy green, which give the
grateful color TO the summer foliage. Then
over all Is drawn thin film of skin,
made up Of empty cells, to protect the whole
from the sun and changes from without, and
TO keep the moisture in. But not TO keep
all the moisture in, for the dry epidermis is
pierced with myriads Of holes, not ragged,
nor yet wholly round and each little open
ing is bordered by Two moist half-mcon cells.
which sit guarding the opening through
which the air comes and goes; and if there
come too little moisture from the roots of the
plant, these little sentinels shut the door,
the opening, more or less tightly, and keep
back the precious moisture and when a full
supply comes. they open the portal and send
out the oyerpussage. By some delicate
signals. these guardians seem to know just
when to open and when to shut the gates.
Upon the epdermis often hairs or glands
will be found, giving the peculiar covering,
woody, silky, downy, hairy or hristly, as 1t
may be, to the outer leaf.
The leaf so curiously made up, how many
shapes it takes. Count the different plants
and You will begin to number the varied
shapes OF the leaves. Look at them. Lay
side by side such as you can find. Take this
and that. 1t Is now lance and now heart,
now an arrow and now an orb, now an old
time halbered and now the same old time
shield. it is now an awl and now
wedge it is now a spatula and now spear,
it is now pitcher and now hand, it is now
many of these in one, and Iow none Of all
these forms. From the narrow needle of the
pine it broadens to the Victoria water lily's
foliage, vide enough for family bed.
Gather leaf from any plant and observe
its border The wooden frame may be filed
quite to the edge, giving rounded outline,
or this same edge untitled will be wavv or
more Sharply scalloped, or set ike the teeth
of saw. The clefts between the teeth may
deepen and reach down half way. or again
sheer down to the foot stalk, and we will
have leaf upon leaf, a compound leaf. These
leaves may be cut again and still again, un-
til the family leaf. like the family tree, has
its children and children's children. bearing
stalkles upon stalk, and leafe; upon leaf.
Yet these, whether simple or complex. are
the same organ and perform the same office
He lives on West Adams street, and. like
most little b6ys, is given to asking great
iaany questions. Wandering with his
mother in the door-yard the other evening.
be drew his attention TO one OF the bright
- L ! l. N