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Submerged plants are useful in their function of absorbing or
destroying impurities and liberating oxygen, keeping the water clear and
pure, and establishing a natural balance between plant and animal life.
They are indispensable in spawning places and provide protection for young
fish.

Myripphyllum and ludwigia are two of the most brilliant of
underwater plants. The myriophyllum has fine, hairy leaves resembling
plumes, and graduating in colors from red to green. One specie is called
mermaid weed, or Proserpinaca. The same feathery tendrils are known as
parrotfeather, although there is another subaqueous plant that goes locally
under that name. Prosorpinaca may be grown in fountain basins only partly
submerged, but it needs earth in which to root.


Plants Suitable for Fish Pools

Ludwigia is named for a Leipsig botanist of the early eighteenth
century. The small, round leaves grow in thick clusters of brilliant hues,
usually a glossy-bronze green on top, and pink to crimson on the under side
[sic]. The small, yellow flowers develop into seed-bearing caps known as
seed boxes, or rattle boxes.

A great many species of this plant are distributed over temperate
regions. It frequently grows out of water in muddy places, but in such
habitat the leaves turn brown in summer. The ludwigia is variously called
cereal-ludwigia, loosestrife, coral fern and rose fern.