The Monmouth inquirer. [volume] (Freehold, N.J.) 1865-1933, 1905-11-30
SENSE ORGANS IN PLANTS.
Light Perceiving Leaves That Have
Eyes and EyeIashes.

DR.. G. Haberlandt, professor of bot
any in the University of Gratz, cele-
brated for his revelations on the sense
organs in plants, is their champion
who tells the world that, having eyes.
they see.
The first question for DR.. Haberlandt
to solve was what part of the leaf was
sensitive to light. BY covering the
leaf with black paper he shows that
the principal and most delicate sensi-
tiveness resides in the blade, although
a coarser ard secondary sensitiveness
to the incident light is found in the
stalk.
This meant that the blade of the leaf
must contain the eyes, if eyes there be.
Anything corresponding to an organ
for sight, he reasoned, would be on
the surface So he looked for the
ocelli, as he terms the light perceiving
organs of plants, in the epidermis Gov
ering the upper surface of the leaf.
1t can also be seen, as the botan-
ical oculist discovered, that the rela-
ton of the spot of light to the sur
rounding part which is more or less
dark, changes when the light falls
obliquely. So when leaf is illuminat-
ed obliquely he considers that it is
stimulated to curve by the fact that
the spots of light are not central in the
cells, and the curving ceases when the
brightest illumination is once more in
the center. So the plasmic membrane
of this inner wall of each cell in the
epidermis becomes the retina of the
eye, or, in scientific phrase, has a
quasi retinal function by which the
leaf is believed to orientate itself in re-
gard to light
Proceeding, DR.. Haberlandt exam
ined the eye and found that it was
good well fitted to concentrate light 1t
is commonly lenslike in form, the outer
wall being convex, the inner wall Ell
Their plain or curved.
Plants have not only eyes, but eye
lashes. The tropaeolum, the handsome
cousin of the ford fuchsia, is one of
the proud plants that can vaunt them
selves on the luxurious comeliness of
fine lashes. The leaves of this plant are
unwettable and when immersed re-
main coated with a silvery mantle of
air. The waxy layer which gives this
quality may be removed by painting
the surface with diluted alcohol with
out injury to the leaves. The result of
immersion is that normal leaves, pro
tected by a layer of air. react normal
~ to oblique illuminations-tha is,
they see, whereas the wettable leaves
whose waxy bloom has been removed
have lost their eyesight, their power of
reacting, says the Chicago Tribune
In all Dr. Haberlandts experiments
he always has found his ocelli (eyes) on
the upper and not the lower surface Of
leaves And he also found them tend
ing to occur especially near the edges
of leaves just in those regions where
the amount of movement correspond
ing to curvature through given angle
is greatest.
The position of the eyes is in the
most advantageous position possible
for the eyes to receive the rays of the
sun and yet be shielded from exposure
The eyelashes droop directly over the
eye itself when showers come, and the
leaf turns slightly so that the eyelashes
form a perfect protection. Also. if the
leaf is exposed to too great heat from
the sun the lashes droop again, shad-
ing them.
The eyes of leaves vary greatly, ac-
cording to the professor, in different
plants and trees, and he believes the
sense of sight much more highly deyel-
oped in the rapid growing and tropical
World.