The Republican. [volume] (Oakland, Md.) 1877-current, 1895-11-14
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GROWTH OF PLANTS.
How They Adapt Themselves to the Re-
gion In Which They Stand.

How They Adapt Themselves to the Re-
gion In Which They Stand.
A red beech tree growing in the
open, where it is Immediately ex-
posed to the effects of the light, has
small but relatively thick leaves.
Red beeches, as underground in the
shadow of the woods, are distinguish
ed by considerably larger but thinner
leaves. The cause Of this variation
lies chiefly in the difference in the
conditions of Transportation. The
growing leaves in the isolated tree
give out moro vGpor to the atmos-
phere than do those in the shade.
The increased evaporation affects the
structure of the leaf surface, and
they are compressed, chiefly because
less air space is found between their
cells, and partly also because the
cells turn perpendicularly to the sur
face instead of increasing in breadth.
All this increases the thickness of the
leaf at the cost of its superficial diam
eter. This condition is Immediately
useful to the plant, because thin
and comparatively broad leaf surface
would transpire too rapidly in an
open situation, involving the tree in
danger of drying out In the shade,
on the other hand, large surface is
necessary to give as much vapOr out
to the atmosphere as the life proc
esses of the plant require, for evapo-
ration promotes the accession of food
salts from the soil. These salts, dis
solved in water, reach the plant and
are retained by it, while the water is
evaporated. More rays of light fail
upon a large leaf than upon a small
one.
In this view, too, then, an enlarge
ment of the leaf surface is more adj
vantageous and useful in a feebly
lighted situation. The intense light
which falls upon a fully exposed
beech may in its greater intensity,
perform as much or even more work
on the smaller leaf as the DINNER
light of the shady situation on the
larger one. An equivalent gain is
realized by the lengthening of all the
parts of the branch which takes place
in the obscure situation. The leaves
are thereby further separated on the
limbs and do not cover one another.
1t is different in the isolated tree,
where the leaves, even in a compress
ed situation, do not suffer for want
of light. Hence, too, the great differ
ence in the appearance of the conical
crown of solitary beech with its
thickly compressed limbs and leaves,
and that of the loosely spread out,
umbrella shaped underground which
the red beeches form in the shade of
the wood.
A dry location promotes the same
processes of growth as increased
Transportation. The need of a plant in
a dry soil is to reduce Transportation,
and correlative processes are mani
tested through which that result is
reached. The growing plant is so af-
fected as to acquire similar struc-
ture to that of a plant in very sun
ny situation. The corrclative opera
tions in many plants take the form
of giving hairy covering to their
leaves. A layer of air retaining hairs
diminishes evaporation. Hence the
same plant may be hairless in moist
ground, and in dry be covered with
numerous hairs. The same is the
case in plants from which the water
supply is taken away.-Popular
| Goionoa Mor+b1y