The Republican journal., 1904-10-13
AUTUMN LEAVES.
The Cause of Their Autumnal Change Of


Color.
This exquisite sunset of the year be- |
gins with the grasses that turn golden
and orange and red. Then it affects |
the low-lying heritage the running |
vines. Before October has arrived the |
woodbine is darkly REDEEMED and the |
poison ivy; and early in this month we
enjoy the deep blood olor of the flower
ing raspberry, the brighter red of the
blackberry leaves, and soon the sumacs
are ablaze all along the roadside and by
the edges of the woods. Reds, lakes
and warm brown seem, indeed, the pre-
vailing tints of October, yet yellow is
abundant. Among the earliest trees to
turn are the scarlet naples, doubly con-
spicuous because still surrounded by so
much green. Equally scarlet is the
dogwood, and later are certain oaks;
other oaks are deep crimson or greenish
yellow. Yellow is the color of the hick-
cries, the chestnuts, the poplars, the
beeches and some other trees, while the
ashes are noticeable for their curious
mulberry or purplish lake foliage at
this season, and the cedars become
rusty olive. Much of the beauty of this
adorable season comes before frost and
cold have reached us at all; and, in fact,
many kinds of leaves become discolored
and fall in mid-summer-thOse of the
pines and hemlocks, for example In
hot climates the process takes place
gradually, throughout the year, new
foliage constantly replacing the old, one
leaf at time. In tropical or sub-trop-
ical regions, where long, hot, dry
period follows a short rainy one, most
trees become brown and presently per-
fectly bare, reviving and putting forth
fresh verdure when the next rainy sea-
son begins. Here the denudation of
foliage is in preparation for the heated
resting season enforced by drought. In
the north it is the preparation for cold
weather, when great harm would come
to trees were they filled with the rising
sap which the presence OF growing
leaves induces.
The primary cause OF the whitening
of the leaves in autumn, then, is the
chilling of the soil, and the process adj
vances far before it is accelerated or
completed by freezing. Roots are
unable to absorb as much water in
it altogether in very cold earth. They
ought not to be urged to do it by the
pumping leaves; and so the leaves, part |
ly to relieve the plant of their demand, !
are cast off With the first reduction |
of temperature in the soil and conse- |
quent lessening Of water with its dis
solved sustenance) from the roots, the !
protoplasm begins to withdraw from |
the leaves. In evergreen" leaves, !
which are fitted by their properties to
resist wintry influences, the grains of
green coloring matter (chlorophyll sink
to the cells underlying the surface, and
are half hidden, so that these leaves
become dull in color, yelled under a
film of empty surface cells. In the
leaves of deciduous trees, however, |
such as our ordinary hard woods, the |
disappears altogether, re-
treating with the other protoplasmic |
materials into the branches, stem, and |
other more sheltered parts of the plants, |
there is present in all plants varying |
coloring matter called anthocynia, |
which may include complex group of |
pigments. 1t is usually met with where
cholorophyll is scant or absent, as in
flowers and fruits (Which owes to it
their gay hues), and along the stalks
and skeleton Of leaves 1t is formed
and accumulated especially in fast
growing tissues, so that buds, young
leaves, and sprouting twigs are often
red. The growth of the top of a soft
maple is almost scarlet as it will be
again in October. After it the forma-
ton of green (chlorophylD supercedes it;
but of the accomplishments of the de-
cay of leaves in autumn is the reforma-
ton of antbosyanin, which appears red
in the cell sap, when certain acids are
present and violet when their quantity
is very small. Thus are formed the
scarlet, crimsons, and puppies, in end
less variety of tint, density, and mass,
which paint such leaves as those of the
Virginia creeper, sugar maple, barber
ry, sumacs, and hundred others that
lend glory to our autumn woods. Min
gled with it in some leaves, standing
along with others which for a time seem
plates of pure gold, are innumerable
crystals OF bright yellow oxalate of
lines, and it is to this material that
the yellow of the leaves of poplars, as
pens, birches, and similar trees is due.
1t is a mineral deposit of no further
use of the plant-left there to be thrown
away, and its final service is this of
beauty. Soon both these crystals and
the anthocyanin change to dull hues,
and the leaf becomes dead brown or
white and falls to the ground.-New
York Evening Post.