The lichen class is one of the most common and diverse organisms on Earth. Science knows more than 25 thousand of their species, the system of their distribution is still not fully understood. Their system of two elements is arranged: a fungus and algae, it is this composition that unites a huge variety.
What are scale lichens
The name "lichens" comes from an analogy with the lichen disease that occurs because of their appearance. Lichens are representatives of a unique species, known for having two organisms at once in their composition, an algae and a fungus. Many scientists distinguish a separate class for this type of fungus. The combination of them is unique: the fungus creates a special habitat inside its body, in which the algae is protected from external influences and provided with liquid and oxygen. The fungus consumes water from the substrate, absorbs oxygen, so the algae inside it receives nutrition and feels comfortable. They do not require special soil for their existence, they grow wherever there is air and water, even in minimal quantities. Scale representativeslichens cover bare rocks, stones, grow on clay, on roofs and trees.
In a favorable environment, in the process of photosynthesis, the algae produces carbohydrates that the fungus feeds on. The latter is a parasite on her body, however their coexistence is rather a symbiosis. It is the algae that is the life-forming component. If isolated from a fungus, it will in most cases be able to adapt to an independent, autonomous existence and continue to develop on its own. The fungus will definitely die without the nutrition it received.
Territories of scale lichens
Lichens are one of the most widespread microorganisms on the planet. In almost every latitude, scale lichens can be found that can adapt to any conditions. Adapted to the cold, they feel good on the slopes of the polar rocks, they are comfortable in the tropics and deserts.
Scaling lichens are distributed throughout the planet, they do not require unique specific conditions. Depending on the type of substrate and climate, one or another species grows on the ground. Growing, they cover huge areas, completely filling the slopes of the rocks and covering the stones.
As a rule, groups are tied to climatic conditions or to a natural area. Some species can be found only in the Arctic, others only in the taiga. But in this system there are a number of exceptions, when the geography of growth is associated with environmental conditions that are repeated in different regions. These lichens live on the banksfreshwater lakes, oceans, mountains, etc. Also, distribution can be tied to certain soil features: some groups of lichens grow on clay, others on rocky soil, etc.
In addition, there is a small category of species that grow all over the world, regardless of natural or climatic conditions.
Environmental value
In the ecological system of the planet they are everywhere. The value of lichens is great, these organisms perform a whole layer of work. They occupy an important place in the formation of the soil, they are the first to penetrate into the layers and enrich it for the further growth of other species. Scale lichens do not need a special substrate, covering the territory of barren soil, they enrich it and make it suitable for other plants. In the process of growth, they release special acids into the soil, due to which the earth becomes loose, it is weathered and enriched with oxygen.
The favorite habitat of scale lichens, where they feel comfortable, is rocks. They confidently attach to rocks and cliffs, change their color, gradually creating conditions for the development of other species on their surface.
Many animals are color-matched to one or another type of lichen that grows in their habitat. This allows you to camouflage yourself and protect yourself from predators.
Exterior structure
The appearance of these symbiotic mushrooms is extremely diverse. Lichens, scale orcrusty, so called because they create on the surface where they grow, a crust resembling scale. They can take on many shapes and come in unexpected colors: pink, blue, grey, lilac, orange, yellow or more.
Scientists distinguish 3 main groups:
• scale;
• leafy;
• bushy.
Characteristic signs of crustaceous lichens - they firmly adhere to the ground or other substrate, it is impossible to remove them without damage. Such lichens are most common in cities, where they can grow on concrete walls and trees. They are also often found on the slopes. Wherever these lichens are found, their scale varieties do not require any essential conditions and feel great even on stones.
They are a crust that covers surfaces unsuitable for life of other plants. Due to the peculiarities of their structure and appearance, they can be imperfectly invisible and merge with nature. All such mushrooms are mistakenly called moss, moss is just one of thousands of varieties of lower plants.
Distinguishing scale lichens from other species is very simple. Leafy plants are attached to the soil with the help of sprouts that resemble small stems. The body of the lichen itself has a leaf-like appearance of various shapes, their sizes can also fluctuate.
Bushy have the most complex external shape. They consist of twigs, round or flat, can grow on the ground, rocks. They are the largest, growing and can also hang from trees.
Calc scale lichens may have a transitional position between these groups and features of other species: this classification focuses solely on their external features.
Internal structure
The body of scale lichen, or thallus (thallus), is of two types:
• homeomeric;
• heteromeric.
The first type is the simplest, in which algae cells are contained in a chaotic manner and are distributed fairly evenly between the hyphae of the fungus. Most often, such a structure can be found in slimy lichens, for example, in scale lichens of the genus collema. In a calm state, they look like dried crusts, and under the influence of moisture they instantly swell, taking on the appearance of leafy lichens. You can meet them on the Black Sea coast.
Heteromeric lichen thallus has a more complex structure. Most scale lichens are of this type. In the context of this type, its structured internal organization can be traced. The upper layer forms a fungus, thus protecting the algae from drying out or overheating. Below the fungus has branches that are attached to the cells of the algae. Below is another layer of vulture, which is a substrate for algae, with its help, the desired level of humidity and oxygen is maintained.
Lichen groups
By the type of growth and attachment to the type of substrate, the following groups are distinguished among scale lichens:
• epigeic;
• epiphytic;
• epiletes;
• water.
The first group, epigeic lichens, is distributed on various soils, they also grow well on stumps and rocks. They can easily withstand competition with plants of higher groups, so they grow infrequently on poor soils, preferring fertile land. Some of them grow in dry swamps, along roads, in the tundra, where they occupy vast territories, etc. The most famous species are lyceum, pertusaria, ikmadofida.
Epigean can also be divided into two more categories: moving (belong to other species) and fixed on the soil lichens, scale to a greater extent. Attached scale can exist on sandy, limestone, clay soil. Crustaceous lichens have the following names in this group: twisted ramalina, dark brown parmelia, collema, pink beomyce and others.
Epiphytic lichens grow exclusively on trees or shrubs. They are also conditionally divided into two groups: epiphilic (exist on leaves, bark) and epixial, arising on fresh cuts. In most cases, they are found precisely on the bark, in a tiny area a couple of dozen different types of crustaceous lichens can coexist simultaneously, completely changing the color of the tree and creating an external new surface.
Scaling lichens of the epilithic group settle on stones and stony rocks. Their examples are varied: some grow exclusively on limestone, others prefer silicon rocks, others settle here and there, as well as on city roofs and walls.
Viewsscale lichens
Scallop lichens come in all four types accepted in science: epilithic, epigeic, epiphytic and epixyl. They can grow on tree trunks, on dead wood, on stumps, but most often they grow on bare rocks.
Scale lichens grow on a variety of substrates. Examples can be easily found in any city or forest: on walls, roofs, stones, rocks. They adhere so tightly to the soil that it is impossible to remove them without damage.
Scale lichens form a crust similar to scale. They can have a very different color, and, completely covering the subject of the landscape, significantly change its appearance. Pink rocks, purple, bright yellow stones make the scenery bright and unusual.
Aspicilia, hematoma, lecanora, lecidea, graphis, biatora are the most famous scale lichens, examples of their growth are found almost throughout the country. A variety of biator can exist simultaneously in swamps and on stones. Lecanor scale lichen, for example, can grow on various substrates: both on stones and on trees or stumps.
Reproduction of scale lichens
There are three ways of reproduction: vegetative, sexual or asexual. Sexual reproduction is one of the most common ways: lichens form apothecia, perithecia or gasterothecia - these are various bodies inside the body in which spores develop. Their development is extremely slow and can last up to 10 years. After this processends, gasterothecia begin to produce spores, which later germinate at the right temperature and humidity.
With asexual sporulation of lichens, spores arise and develop right on the surface.
Vegetative propagation involves tiny substances consisting of particles of algae and fungus, and thallus bushes. They spread with the wind or animals, traveling until they find a suitable substrate. This is the fastest way of reproduction, contributing to the rapid spread. Reproduction in this way can also occur with an unprepared piece of lichen, but in this case the chances of growing on a new substrate will be lower.
Application
The use of scale lichens is unusually wide: they are able to grow where there is no chance for any other plant. Over time, they prepare the necessary environment, a sufficient amount of humus for the growth of other plants. At the same time, out of the many thousands of lichens, only two species are poisonous, the rest are used in various fields: in agriculture, medicine.
The use and importance of lichens in pharmacology is also great: healers in the villages know the beneficial properties of each of the hundreds of species, using them to treat a wide range of diseases: from coughs to oncology. Scale lichens are especially effective in the treatment of purulent inflammations. They are carefully cut from the surface and applied to the wound - thanks to the antibacterial properties and antiseptics contained in their composition, they destroybacteria, promote cleansing and healing of an open wound.
Measuring the state of the environment with lichens
In science, they are also used to study environmental conditions and air quality. Scale lichens are the most resistant to the deterioration of natural conditions, they endure environmental disasters and high levels of air pollution, but this significantly affects their condition. Due to the peculiarities of their structure, lichens absorb incoming water and air without additional filters, all at once with the thallus. Because of this, they are sensitive to pollution and changes in the composition of air or water, as toxins instantly disrupt their inner workings.
Due to the high content of toxic substances in the atmosphere or water, there are cases of mass death of scale lichens. The first such cases began to occur near large industrial cities, where production is developed, and, consequently, a high level of air pollution. These cases clearly demonstrated the need to filter emissions of harmful substances into the air. Today, lichens are growing again in large cities thanks to environmental care and improved air quality.
There are two ways to study the state of the air according to the state of representatives of this species: active and passive. With the passive, conclusions are drawn about the state of the atmosphere here and now, while the active implies a long-term study of a certain type of lichen, which makes it possible to get a more accurate picture.
