Morning journal and courier. [volume] (New Haven [Conn.]) 1848-1894, 1889-10-14
The Oak Leaf.

Sir John Lubbock read paper on the
shape of the oak leaf before the British as
sociation the other day, in the course of
which he said:
"We are SO accustomed to the form of the
oak leaf that it does not strike us as any
thing peculiar, and comparatively few per-
haps have ever asked themselves why It
should be as it is. And yet 1t is peculiar,
unlike that of any of our forest trees and
those of the evergreen oak so abundant in
hotter countries. In botanical phraseology,
they are deciduous, oblong oblaneeolate, or
oblong-elliptical, sinuated, with blunt lobes
extending not more than half way down to
the mid-rib. The sinus between the lones Is
generally rounded off at the bottom. Again,
though have not found this mentioned in
the botanical works which have consulted,
they are rarely symmetrical, the lobes of the
two sides not corresponding. The three
points then, which give the oak leaf Its Pc
culiar form are: Q) the deep, rounded sin-
uses; (2) the want of symmetry of the two
sides; (3) the oblong or oblanoeolate outline.
81 do not know Of any attempt to explain
this peculiar form. As regards the sinuses,
Kerner suggests that they are intended to
permit the passage of light to the lower
leaves. would not deny that the space be-
tween the lobes may be Of some advantage
in the manner suggested by Kerner, but
greatly doubt whether this is the main pri-
mary explanation. That which would sug-
gest is as follows: The leaves of the ever-
green oaks are entire and small in compare
son with those of the English oak. During
the winter and early spring they are protect
ed by series of brown scales, inside of
which they lie. and with which they form
the well known buds which are SO familiar
to us. and which are both small and short in
proportion to the size of the leaves them
selves. In cooler and moister regions, on
the contrary, there is, as we know, tenden-
cy for leaves to become larger and deciduous.
I will not now enter into the reasons for this;
but the fact will not probably be denied.
These influences do not, however, affect the
outer scales, which remain as before without
any increase of size. But a. the leaves have
increased in size, and the scales have not,
the leaves can no longer retain their original
arrangement In the bud. If, for instance,
we compare the buds of the oak and of the
beech, We see that while the leaf of the oak
is longer than that of the beech, the bud of
the oak is, on the contrary, shorter than that
of the beech. Under these circumstances
what must happena The leaf grows and be-
comes longer than the bud. 1t is, therefore,
necessarily bent into curve. But an entire
leaf, if thus thrown into curve, would ne-
cessarily fall into folds, the number being
determined by the number of ribs or veins.
For such folds, however, there would be no
room within the narrow limits of bud, or
rather, perhaps, they would be inconven-
lent, because they leave more or less empty
spaces.
"This may be rendered more clear by taxi
ing piece of cloth or of paper, folding it up
and then throwing it into a curve. 1t will
then necessarily fall into one or more folds.
If it were strengthened as an oak leaf is, by
three or four side ribs, there would be fold
between each two ribs. As matter of fact,
however, from the absence of space the mem
brane, where the fold would be, is not actu-
ally developed. We may initiate this by re-
moving them. If this be done the result will
be the formation of sinuses rounded at the
base closely resembling those 80 charaeteris-
tic of the oak leaf. These sinuses are due
then, as believe, to the curvature of the
leaf owing to the shortness of the bud in
comparison with the length Of the leaf. The
young leaf is not only curved, it is wrapped
round the interior leaves. The result of this
is that one side of the leaf is folded within
the other; the one therefore, being on the
outer side, has more space than the other.
The two sides of the leaf are, in fact, differ.
emily situated. and this, I believe, accounts
for the second point-namelv, the want of
symmetry. The oblong form Is an advan-
tage from the way the leaves diverge from
the stalk. In this manner the interesting
peculiarities of the oak leaf may be account
ed forn