What is moss? Structure, reproduction, moss species, their significance and application

To understand what mosses are, you need to study the oldest group of plants. This group is of the highest type, isolated and numerous. In our time on the whole planet there are almost 30 thousand varieties of mosses.

Classification

Botanists discovered and investigated all known species of bryophyte plants, the classification of which is based on differences in the morphological structure, the ways of distribution and the structure of spore bolls. The department of mosses can conditionally be divided into such classes: deciduous, hepatic and anthocerot mosses.

Hardwood Mosses

What are moss deciduous? They are otherwise called briopsides. This is a large class, numbering about 15 thousand species. Representatives of this group are recognized as the most highly developed of all plants in this department. Briopsides are very diverse, both in shape and in size. Sometimes they reach considerable sizes. The most viable stage of their existence is the gametophyte. The plant looks like a stem with single-layered leaves spirally arranged. Bryopsids reproduce by spores. They are distributed in the tundra, marshy and humid areas. Representatives: kukushkin flax, sphagnum moss.

Hepatic Mosses

What are hepatic liverworts? They have about 8,5 thousand species and are divided into two subclasses: marshantsievye and yungermannievye liverworts. The predominant viable stage is the gametophyte. Externally, the plant resembles a flattened "stem" with leaves located along. Propagates by spores with the help of elasters (special springs). Liverworts are common in tropical and temperate-humid climates. Typical representatives: blepharostroma hairy, marshansiya polymorphic, barbilophosia mound, ptytidium ciliate.

Anthocerotic mosses

What is anthocerot moss? This class of moss specialists are often regarded as a subclass of hepatic mosses. It includes almost 300 species.

In the life cycle , the sporophyte stage predominates. Externally, the plant looks like a rosette-like or lobed thallus. These mosses occur in temperate wet and tropical climatic zones. The class representative is anthoceros.

The generalized characteristic of mosses

So, what is moss? These are stunted plants, the height of which can vary from 1 mm to 60 cm. They grow on the trunks of trees, on the walls of houses, on land, in fresh water bodies and swamps. Because of intolerance, salt plants do not occur in the seas and saline soils. Most often the structure of mosses is very simple - stems and leaves. But the roots of the plants are absent altogether. Water and nutrients they absorb with rhizoids or the whole body. Adaptation to terrestrial existence has led to the fact that mosses have integumentary and mechanical tissues, as well as new cells that perform a conductive function. The plant is a perennial, most often of a small size (only a few mm high), less often large (up to 60 cm). His body looks like a thallus (anthocero or individual liverworts) or is divided into "stem" and "leaves". Attachment to the substrate and absorption of water is carried out by the outgrowth of the cells, the so-called rhizoids (they usually do not have a conducting system).

The structure of sphagnum mosses is also not complicated by intricacy. These are large light green or slightly reddish puppets. They have upright "stems", with pear-shaped, leafy "branches." Without rhizoids, the moss stalk is erect (gradually dying from below), leafy in several rows, with numerous oblong lateral processes that are collected at the apex of the stem into a dense head. For the rest of the stem branches are collected by bundles. The latter consist of 3-13 branches, which hang down and stand away from the stem. At the top, "branches" are shortened and collected in a dense head. Colorless aquifers with pores make up the outer layer of the "stalk".

Single-layer "leaves" of sphagnum include cells of two types: photosynthetic and aquiferous. The first have a worm-like shape and contain chloroplasts located between aquifers. There are many such cells, which allows sphagnum to suck in a large volume of water. Sporophyte sphagnum is a box of round shape, in which there are spores, with a lid. When the spores mature, the pressure inside the capsule increases, as a result of which the cap opens, and the mature spores are ejected outward. This process takes place in warm weather for better spread of the dispute.

What is moss green? To their bright representatives it is possible to carry kukushkin flax. Its "stalk" is covered with hard, dark green subulate "leaves". It has rhizoids and grows to 30-40 cm. The leaves of the moss are bent and erect, with an elongated membranous vagina and a vein protruding from the apex. "Stalk" has a primitive conducting system and dioecious gametophytes. The top of the "stems" is completed by antheridia and archegonies. From the zygote after fertilization develops sporophyte, which is a box on a long leg for the maturation of haploid spores in it. The capsule is covered with a falling cap with thin, drooping hairs, like linen yarn. The moss box is divided into a lid, neck and urn. Inside the box there is a "hidden" column filled with infertile cells. A sporangium is located around the column. Urnochka and cap are bordered by a ring consisting of cells with thickened walls. This ring is responsible for dropping the urn and its separation from the lid.

Methods of reproduction of mosses

The sex generation in the life cycle of the plant predominates over asexual. The organs of reproduction of moss are formed directly on his body. These are the archegonia and antheridium mentioned above. Archegonians are responsible for the formation and development of one immobile female gamete, and antheridium - for the many gametes of masculine. In the fertilized female gamete (condition - the presence of water) begins to develop asexual generation of moss - sporophyte. This is a kind of box on the leg, attached to the body of moss. It contains many spores that are able to germinate under favorable conditions, forming a new plant. Some species are able to reproduce in a vegetative way. In this case, the adult body is separated by a thallus, which is attached in close proximity to the plant, and begins to exist and reproduce independently.

Distribution of mosses

It is more difficult to determine where there is no moss, than to tell where the moss grows. This representative of the flora is widespread almost everywhere - from the tropics to the polar regions. In tropical regions, moss grows mainly in mountainous areas and forests, i.e., where the increased humidity of air prevails. Sometimes the soil covered with mosses is also found in arid territory, since the plant has the ability to temporarily stop its life activity in the dry period, and with the appearance of moisture, renew it. In general, mosses predominate in the temperate and subarctic belts of the northern hemisphere.

Moss and its meaning

The value of moss in nature is enormous. First, thanks to these representatives of the plant world, the landscape water balance is regulated, because they are able to accumulate large amounts of moisture in the tallum. Secondly, the plant moss creates a special biocenosis, especially in such areas, where it completely covers the soil. In addition, this group has the property of accumulating and retaining radiation. The value of moss for animals is also great, because bryophytes are the main type of food for some individuals. And in the life of a person this plant also plays an important role. So, many types are effectively used in pharmacology. And peat, formed after the death of mosses, is used as fuel.