Interesting fern - salvinia floating

Fern Salvinia floating - small, floating on the surface of water reservoirs plant belonging to the Salviniev family. This type of Salvinian genus is the only species that grows on the territory of the Russian Federation. The plant is often cultivated as an aquarium plant.

Salvinia floating: structure and appearance

This is an annual fern with a thin stem reaching fifteen centimeters in length and having a whorl of three leaves on each knot. The stem floats on the water surface. Its two leaves are integral, ovoid-elliptical and slightly heart-shaped. They are covered with warts on top, which on the tops contain a bundle of thick short hairs. The lower surface of the leaves has a dense cover of brown hairs holding air bubbles. This makes it possible for salvinia to be retained on the water surface. The third sheet is underwater, it is cut into filamentary lobes covered with hairs and very similar to the outward appearance of the roots. In fact, it just acts as a root: sucks water and nutrients, and also stabilizes the fern.

Life cycle of salvinia floating

At the base of the leaves under water, there are bunches of four or eight globes of spherical shape. Some of them contain macro- and microsporangia, and later they form female and male gametophytes. Each megasporage has four megaspores, but only one of them develops. Typically, sixty-four microspores are formed in one microsporangia.

As a rule, in the fall, the Saurus falls and sinks to the bottom of the reservoir. There they winter, and by the spring their shell is destroyed. Sporangia float to the water surface and germinate. After the breakthrough of the wall sporangia microspores form a male three-cell gametophyte, and then two spermatogenic and two infertile cells form from its two cells. Of these, each produces four spermatozoa. Sprouting, the megaspora also breaks through the shell, forming a female gametophyte. It forms three archegonies, but after fertilization only one of them develops.

Distribution area

Salvinia floating has a fairly wide range: it is common in the waters of Africa, temperate and tropical regions of Asia, as well as in the southern and central regions of Europe. On the territory of the Russian Federation, the fern is found mainly in the south of the European part, in the Far East, in Western Siberia. Salvinia floating is widespread in water bodies with slowly flowing or standing water, especially often it can be seen in the starets of large Russian rivers.

Application and meaning

On the surface of water bodies, this fern, like other kinds of salvynia, forms dense thickets that cover the access of light to a water body, which often leads to significant changes in the reservoir of ecological conditions. As a result, in many Salvinia states floating is considered a harmful plant. Nevertheless, this fern also has useful properties: thus, its thickets serve as an excellent refuge for fish fry.

As already noted, salvinia floating is cultivated as an aquarium plant. However, it is bred not only as a decorative element of the tank, where fish are kept, but also as a good natural shade for other plants that prefer diffuse light.

Fern Content

It is best to place salvinia floating in moderately warm or tropical aquariums. To the conditions of containing special requirements the plant does not show. For him , neither water hardness nor acidity matters - in both soft and hard water the fern grows equally well. The temperature in the aquarium should be maintained at a minimum of 24 degrees Celsius. If the water is heated to only 20 degrees, the growth of the plant will slow (the leaves will become smaller), but it will not stop at all.

If your aquarium has a salvinia floating, you should regularly change the water. As devices of artificial illumination of the tank it is recommended to use phytolamps having power from three watts per liter, and fluorescent lamps. If you use incandescent lamps, then make sure that their power is small, otherwise you can dry the air.