Submerged Oxygenating Plants
The principal functions of these plants are
to provide additional oxygen, supply the fishes
with green food, protect the small fry and to
act as depositories for the fish's eggs. They
should be planted in the shallow part of the
pond in from a foot to eighteen inches of
water. Some species, such as Anacharis,
spread so rapidly that, unless planted where
they can be controlled easily, they should be
avoided.
The plants in the following list marked with
an asterisk are sold usually in weighted bunches
and are rootless. Do not stick the stems into
the soil nor yet ' plant' by just dropping the
weighted bunch into the water. Instead,
separate it into small bunches containing three
or four shoots and tie a small stone to each.
Then drop the bunches into the water so that
they settle about six inches apart ; thus, as
they thrive, the area so planted will become
a respectable mass of greenery.
The plants not marked with an asterisk
have roots, the crown of which, when planted,
should be just above the soil. They send out
runners, usually, which root at intervals-like
the strawberry plant-and form a carpet of
greenery on the bottom.
The following plants are listed, approximately, in the order of their oxygenating
value.
*Elodea. Four species of this invaluable
plant are cultivated for pond and aquarium.
The most common species is Elodea Canadensis,
otherwise Anacharis, but compared with the
other species it has
a weedy look and
does not improve
the aquarium.
E. callitrichoides
has bright green
slender leaves,
E. crispa has the
leaves curled back
and so dense as
to make each stem
look like a green
tube, and E. densa, similar in appearance, has
dark green leaves. These species are by far
the best for either pond or aquarium.
Vallisneria or Tape
Grass. This valuable
oxygenator and highly decorative plant
has long, slightly
twisted leaves, the
length of these depending on the depth
of water. In some
varieties the leaves
may be two feet or
more in length. Reproduction in Vallisneria is by means of
runners.
Sagittaria. Nearly
twenty different species of
Sagittaria are cultivated
for aquarium and pond
purposes. Some species
have the greater part of the
leaves out of the water as
well as the flowers, others
are completely submerged.
The leaves, according to
the species, may be
arrow-shaped, strap-like, slender or broad.
The best kind for the aquarium or small
shallow pool is S. natans, this has a profusion
of submerged slender leaves with floating
flowers : S. brevirostris is splendid also for
the small pool, the flowers and their stems
alone stand out of the water.
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