Another fun old book
Kevin Snively (ksnive@premier1.net)
Wed, 25 Oct 1995 03:14:04 -0700 (PDT)
The following has been prepared and presented purely for
its historical content and entertainment value. It is full
of errors amoung others Fig. 11 labeled as an Australian
pitcher plant is actualy a Sarracenia. Take this with a
few grains of salt. I hope you find it as much fun as I
did.
krs
Stories of the Universe
The Plants
By Grant Allen
1909 New York Review of Reviews Company
(C) 1895, 1902, by D. Appleton and Company
Chapter V. "How Plants Drink"
Beginning near the top of page 63 and ending on page 68
Moreover, nature sometimes even goes in for
deliberate manuring. Plants like buttercups and daisies,
that live in ordinary meadow soils, to be sure, get enough
nitrogen and sulphur and other such constituents from
the mould in which they are rooted. But in very moist and
boggy soils there is generally a lack of these necessary
earth given elements of protoplasm; and natural selection
has therefore favoured any device in the plants which grow
in such places for obtaining them elsewhere. This they do
as a rule by catching insects, killing them, and sucking
their juices, and using them up as manure for manufacturing
their own protoplasm and chlorophyll. Our pretty little
English sundew is one of these cruel and perfidious plants
(Fig. 10). Its leaves are round, and thickly covered with
small red hairs, which are rather bulbous at the end, and
very sticky. The bulbous expansions, in point of fact, are
small red glands, which exude a viscid digestive liquid.
When a small fly alights on the leaf, attracted by the smell
of the sticky fluid, he is caught and held by its gummy mass;
the hairs then at once bend over and clutch him, pouring out
fresh slime at the same time, which very shortly envelops and
digests him. In the course of a few hours the leaf has sucked
the poor victim's juices, and used them up in the manufacture
of its own protoplasm.
Many other insect-eating plants exist in the marshy
soils of other countries. One of the best-known is the Venus's
fly-trap of tropical or sub-tropical North America. In this
curious plant the leaf is divided into two portions, one of
which forms a jointed snare for catching insects. It is hinged
at the middle; and when the fly lights upon it, the two edges
bend over upon him, and the bristles on the margin interlock
firmly. As long as the insect struggles they remain tightly
closed; when he ceases to move, and is quite dead, they open
once more, and set their trap afresh for another insect. A
great many such carnivorous and insectivorous plants are now
known: and in almost every case they inhabit places where the
marshy and waterlogged soil is markedly wanting in nitrogen
compounds. Insect-eating leaves are thus a device to supply
the plant with nitrogen by means of its foliage, in circumstances
where the roots prove powerless for that purpose.
Simpler forms of the same sort of habit may be seen in
many other familiar plants. Thus our English catchflies and
several other of our common weeds have sticky glandular stems,
which exude a viscid secretion, by whose aid they catch and
digest flies. This is the beginning of the insect-eating habit,
more fully evolved by natural selection in marsh plants like
sundew, and especially in larger subtropical types like the
Venus's fly-trap. If you collect English wild-flowers you will
soon perceive that a great many of them have sticky glands on
the summit of the stem, near the flowering heads; and this is
useful to them, because the flowers and seeds are particularly
in want of nitrogenous matter for the pollen and ovules and the
development of the seed. In short, though plants get their
nitrogen mainly by means of the roots, they often lay in a
supplementary store by their stems and their foliage.
Our common English teasel shows us the beginnings of
another form of insect-eating, which is highly developed in
certain American and Asiatic marsh plants. The leaves of teasel
grow opposite one another, joining the stem at the base, so as
to form between them a sort of cup or basin, which will hold
water. If you look close into this water you will find that it
is often full of dead midges and ants; and the plant puts forth
long strings of living protoplasm into the water. into the water,
which suck up the decaying juices of these insects, and use
them in the manufacture of more protoplasm and chlorophyll. In
this case, water is used both as a trap and as a solvent; the
insects are first drowned in the moat, and then allowed to decay
and digest themselves in it.
Teasel, however, is but a simple example of this method
of insect-catching. Several American marsh-dwellers, collectively
known as pitcher-plants, carry the same device a great deal
further. They are far more advanced and developed water-trap
setters. The Canadian side-saddle plant allures insects to its
vase-shaped leaves, which are filled with sugar and water. This
is just the same plan which we ourselves employ to catch flies
when we trap them in a glass vessel by means of a sweetened
and sticky liquid. The pitchers are formed by leaves which join
at the edges; they are attractively coloured, so as to allure
the flies; and they secrete on their walls a honeyed liquid,
which entices the victim to venture further and further down
the fatal path. But the inner sides of the vase are set with
stiff downward-pointing hairs, which make it easy to go on,
but impossible to crawl back again. So the flies creep down,
eating away at the sticky sweet-stuff as they go, till they
reach the bottom and the hungry water, when they fall in by
hundreds, and are drowned and digested. I have found these
plants often by the sides of Canadian bogs, with a whole seething
mass of festering and decaying insects filling up every one
of their murderous vases. Other pitcher-plants are found in
Australia (Fig. 11)
The Nepenthes of the Malayan Archipelago is a still
more remarkable water-trap insect-eater, in which the pitcher
is formed by a curious jug-like prolongation at the end of the
leaf (Fig. 12). It is provided with a lid, and its rim secretes
a sticky sweet liquid. Insects that enter the jug are prevented
from escaping by strong recurved hooks; and these hooks are so
powerful that at times they have been known even to capture
small birds which had been incautiously entered. This may seem
curious, but it is not odder than the fact that our own English
bladderwort, a water plant with pretty yellow flowers, which
grows in sluggish streams, has submerged bladders that supply
it with manure, not only from the water-beetles, larvae, and
other insects, but also from trout and other and other young
fry of fresh-water fishes. I may add that while the sundew
and other live-insect catchers have to digest their prey, the
water-trap makers save themselves that additional trouble and
expense by macerating and soaking it till it reaches the
condition of a liquid manure, ready dissolved for absorption,
and easy to assimilate.
Thus we see that while roots are the chief organs for
absorbing nitrogenous matter, they are often supplemented in
special circumstances by leaves and stems....
Finis