Daily American organ. [volume] (Washington, D.C.) 1854-1856, 1855-01-12
Lectures at the Smithsonian Institution
REPORTED FOR THE AMERICAN ORGAN.

REPORTED FOR THE AMERICAN ORGAN.
EPIPHYTES AND PARASITIC VEGETATION
By PRoy. Asa GREY, OF HARVARD UNIVERSITY
He commenced by giving brief summary of his
last lecture on Vegetation, beginning with the seed
when first sown, and following it from termination
till the plant has obtained its growth. He then
spoke Of the power of cuttings to. take root, and
illustrated it by adverting to the various creeping
plants which send arootin the ground wherever 1t
touches it and to branches bent down and confined
to the ground which also take root.
Owing to the injurious effects of light and air
upon the growing root, and the comparative dry
ness of the air, we do not ordinarily expect the
stem to produce roots in the free mir and light But
in tropical regions, where the air Is highly sur
charged with moisture and warmth, roots in some
cases do shoot forth in free air in spite of the light
We have instances Of this in the Pandanus, of the
South Sea Islands, and in Indian corn and sugar
cane, where roots shoot forth from the first or
second joint above ground, and grow downward
till they touch the earth, and then take deep hold,
transmitting the moisture to the plant in the same
way as the original root. This is a reason for
Milling" the growing corn.
A much more striking instance is seen in the
Banyan tree, and other trees of the fig family.
Every branch of these trees drop slender fbres
in the air, which grow down till they touch the
ground, and then take root; as they grow they
increase in diameter, prop the parent branch, and
supply it with nourishment by much more direct
route than the roundabout way which the sap must
travel, to reach the branch from the trunk Of the
tree; then the branch sends forth other branches
which drop roots, and they carry on the same pro-
cess as before until grove is formed. The parent
trunk may have died by this time, but large grove
has taken its place. The mangrove is another in
stance of the kind found in South America, forming
thtckets on muddy shores near salt water.
He now spoke Of air plants or epiphytes, which
derive all their nourishment from the air. They
have roots, but they only serve to hold them in
their position-often being found on rocks with
no soil upon Them branches of trees, dead wood,
&C. Lichtens, MOSES, &C., are OF this class, and
seen in every part of the country. He showed
several large and beautiful specimens of epiphytes
which were loaned for the occasion by Mr. Smith,
of the Public Conservatory. Some epiphytes have
beautiful blossoms, and these were shown by large
paintings on the wall
These plants produce minute glutinous seed,
which is borne about by the wind, and, on touch
ing anything, sticks to 1t, and terminates thus re-
producing itself
He next spoke of parasitic plants, which not only
affix themselves to other plants but plunge their
roots into their tissues and draw from them their
nourishment instead of the earth Or air The most
familiar of this kind is the mististoe, growing on
various trees, but, in this country, preferring the
hickory. 1t takes from the wood its crude sap, di-
gests it in it's own green leaves and applies it to
its own purposes.
The cius;a, or cursed fg Of the West Indies, COM
bines this economy with that Of the banyan. 1t
begins as parasite but soon sends out air roots,
like the banyan, thus deriving food from two
AS the air roots descend all sides of the trunk
and strengthen, they sometimes twine themselves
round the parent trunk and strangle it. and, its
decay, the clusa stands Independent, with it's ir-
regular body and contorted arms, looking like a
vegetable spectre in the dark forest.
Now followed history Of the doddsr, which duly
terminates from seed but, having no seed leaves,
is obliged to become parasite or perish. In Eu-
rope, il is often found in fax fields, destroying
them. II has been introduced into America In
foreign Aaxseed, but does little damage.
The color of the plants Of this Kind Is never
green, thus betraying their character. They all
live by stealing He now spoke of and showed a
painting of the Rafelsa Arnold the Titan Of this
kind of plant which is three feet in diameter the
cup of which win hold six quarts, and is one foot
broad each petal Of the same breadth, and the
weight of the flower is fifteen pounds; il is found
in Sumatra. =
He next dwelt on the character of fungi, as
exhibited in mould rust in wheat, smut In rye,
&c, the potato rot, &c. All these pests TO the
farmer, originate in small parasites, which spread
their roots throughthe tissues Of the plants inter
cepting its sap, and thus preventing the grain from
maturing This parasite, though very minute, Is
not to be dsregarded He Illustrated the action
of the various fungi cereals by large paintings,
and explained the action 20 satisfactorily that he
was interrupted by continued applanses.
These fungi not only strike their roots into other
plants, but also into house fies which may often
be seen in the autumn with microscope; the
muscadine which killed so many silk worms, as al
most to cut off the supply Of silk for the year,
kind of fungus; hornets and wasps may be seen
at times with fungi growing out Of their bodies,
nearly MS large as they are; and grubbs are known
TO be killed by like vegetable growth pervading
their whole bodies, and drawing from them the
moisture necessary for their growth.
Cd