The fern has the form of what? What kind of ferny has a fern (photo)

Ferns saw each of us. These herbaceous plants are widely distributed in the temperate climatic zone. And what kind of fern does the species have? The answer to this question you will find in our article.

General characteristics of the department

Ferns are representatives of higher spore plants. These are the first terrestrial plants for which the following features are characteristic:

• The appearance of real tissues and organs;
• Herbaceous life forms;
• Reproduction by asexual reproduction cells - spores;
• Alternation of generations in the life cycle.

Of modern species, except ferns, this systematic group includes mosses, mosses and horsetails. In all these plants the sex and asexual generation differs in the way of reproduction and morphological features. So, the fern sporophyte is a leafy stem plant. This is an asexual generation. But the gametophyte - the fern of the fern, has a completely different shape.

Features of the life cycle

The plant of asexual generation of ferns consists of root and shoot. On the surface, we can only see complex leaves. The very same escape is modified and develops underground. It is called the rhizome. Outwardly this structure really resembles an underground organ. But the rhizome is an escape, because it consists of interstitial sites, nodes and kidneys.

On the underside of the fern leaf, with the naked eye, small brown tubercles can be seen. This sporangia, in which cells are formed asexually. When ripe, they fall into moist soil. There they sprout, forming a fern sprouting. This structure has a completely different form - a flat plate of green color. The dimensions of the sprout are very small - only a few millimeters. Therefore, it is very difficult to distinguish them in the dense cover of plant thickets.

What kind of fern

Despite the microscopic dimensions, the structure and functions of this stage of plant development are quite complex. On the photo of the fern sprout it is clearly seen that it develops separately from the asexual generation. Mostly it has a heart-shaped shape with wavy edges. In the middle, this plate is massive. The edges are thinner, single-layered, slightly translucent.

The fern has the appearance of a heart-shaped plate, in the lower part of which dense bundles of rhizoids are formed. From these roots, these structures are distinguished by the absence of tissues. They consist of cells that are combined anatomically, but each of them functions separately. Rizoids perform the function of attaching the gametophyte to the substrate.

Of great importance for the development of sporophyte is that the cells of the sprout contain chlorophyll. This ensures the process of photosynthesis and the presence of the necessary organic substances for the formation of the asexual reproduction plant, which has more impressive dimensions.

Development of gametophyte

Spores of fern develop only in moist soil. Their distribution occurs with the help of water, wind, insects and birds. As a result of the sprouting of the spore, a plate is formed. In cross-section, its size barely reaches 3 mm. The fern is attached to the ground with the help of rhizoids, which also provides additional nutrition to the plant.

On the underside of this structure are sexual organs - gametangia. These structures also have microscopic dimensions, which are even difficult to imagine. They are of two types. Men are called antheridium. Spermatozoa mature in them. These are germ cells that have flagella. But the movement of spermatozoa is possible only in the presence of water. Therefore, the presence of moisture is a prerequisite for the implementation of the fertilization process in all spore plants. Female genital organs are called archegonia. In them fixed eggs are formed.

Ferns are characterized by cross fertilization. This is due to the fact that the ripening of antheridia and archegonia occurs at different times. Therefore, the fusion of gametes usually occurs between different sprouts.

Sporophyte

From the fertilized egg develops a plant of asexual generation, which predominates in the life cycle of fern-like ones. It is called a sporophyte. If the fern is plate-shaped, the asexual generation is a herbaceous plant. It has an underground modified shoot - rhizome. From the vegetative buds located on it, the leaves develop. They are of two kinds. Young leaves are called vayi. They are spirally twisted and by their nature are pre-biases. Mature leaves of ferns are complex, spreading out.

Between the sexual and asexual fern generation there is one more significant difference. The fern has rhizoids, and the sporophyte has accessory roots.

Ancient species

Modern fern-like plants are of sufficient species diversity. Of all the disputes, this group is the most numerous. This is due to their more perfect structure. At the present stage there are more than 10 thousand species.

But the ancient ferns had a completely different appearance. Their heyday they especially reached in the Carboniferous period. At that time treelike ferns reached up to 40 meters in height. Impressive was the width of their trunks. It was 2 meters.

The appearance of these plants on the planet dates from the Paleozoic era. In the course of evolution, they originated from the first terrestrial plants - rhinophytes. It was 400 million years ago. Ancient ferns died out due to climate change. They are the basis of a valuable fuel mineral - coal.

So, in our article, we found out what kind of fern the fern has - the gametophyte. It is a thin microscopic plate of green color. It represents the sexual generation of ferns. The seed develops separately from the plant of asexual generation, is capable of photosynthesis, has rhizoids. It develops organs of sexual reproduction in which gametes are formed. As a result of their fusion and further development of the zygote, a fern sporophyte is formed, which has a leaf-building structure.