Milford chronicle., 1905-11-24
SENSE ORGANS IN PLANTS.
sisht PereeivinE Leaves That Have
Eyes and EyeIashes.

sA&At &eEccAFAAG Leaves Thmt Have
Eyes and Eyelashes.
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,
Ihey see.
The first question for DR.. Haberlandt
TO solve vas 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 eoarser and secondary sensitiveness
to the incident light is found in tile
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 COW
ering the upper surface of the leaf.
1t can also be seen, as the botan-
zeal 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 a 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. II
is commonly lenslike ia form, the outer
wall being convex. the inner wall Ell
ther plain or curved.
Plants have not only eyes, but eye
iashes. The tropaeolum, the handsome
cousin Of the fOrid fuchsia, is one Of
the proud plants that can Yaunt them
selves on the luxurious cOmeliness Of
fine lashes. The leaves Of this plant are l
and when immersed re- {
main coated with a silvery mantle Of I
air. The waxy layer which gives this |
quality may be removed by painting
the surface with diluted alcohol with '
put injury to the leaves. The result Of G
is that normal leaves, pro- 1
-eeted by layer of air, react normal /
" to Oblique illuminations-that is. {
hey see, whereas the wettable leaves 4
whose waxy bloom has been removed b
ave lost their eyesight, their power of u
eacting, says the Chicago Tribune. il
In all DR.. Haberlandts experiments a
le always has found his Ocelli (eyes) on v
he upper and not the lower surface Of f
caves. And he also found them tend o
1g to occur especially near the edges a
f leaves Just In those regions where u
he amount of movement correspond n
lg to curvature through given angle II
greatest
The position OF the eyes is In the
lOst advantageous position possible .
Or the eyes to receive the rays Of the II
IN and yet be shielded from exposure. a.
he eyelashes droop directly over the y,
ye itself when showers come, and the VI
af turns slightly so that the eyelashes oi
'rm perfect protection. Also, If the "
af is exposed to too great heat from er
le sun the lashes droop again, shad- =
g them. "
The eyes Of leaves vary greatly, ac- " "
riding to the professor, in different u
ants and trees, and he believes the '"
nse Of sight much more highly devel- =. -
,ed in the rapid growing and tropical -
ants than In others.-New York "a 20
'orld. nc