What is the structure of fern - features of leaves, roots of ferns

Fern-like species have been growing on planet Earth since time immemorial. The duration of their existence is in the millions of years. Plants have a variety of life forms, prefer moist habitats. The peculiar structure of the fern makes it extremely adapted for survival.

Description of fern plants

What is fern, there are different versions. Scientists believe that these are direct descendants of the oldest plants - rhinophytes. In the process of evolution, the structure of ferns has become more complex, why ferns are classified as higher plants, no one is surprised. It confirms:

• cyclic plant development;
• advanced vascular system;
• adaptability to the terrestrial environment;

Fern in nature

By definition, fern is a perennial plant, belongs to the genus of spore plants. To the question about fern: is it a shrub or grass, you can answer in the affirmative in both cases. Sometimes it is still a tree.

Additional Information. When describing ferns, one can not help but recall their varied color scheme, delivering aesthetic pleasure. These plants often become a real decoration of sites. Their undoubted advantage is resistance to diseases and pests.

Biological classification of ferns

A huge number of fern species complicates their classification. Such attempts were made by ancient scientists. The proposed schemes are often not consistent with each other. The classification of modern ferns was based on the structure of sporangia and some morphological characters. All varieties are divided into ancient and modern.

The following seven classes of vascular plants, both extinct and modern, are classified as ferns:

1. Aneurophitopsids (Aneurophytopsida) - the oldest primitive group.
2. Archaeopteridopsida (Archaeopteridopsida) - also ancient representatives, which resembled modern conifers.
3. Cladoxylopsids (Cladoxylopsida) - there are versions that this group represents a blind branch of evolution.
4. Zygopteridopsids (Zygopteridopsida or Goenopteridopsida) are a transitional group to modern species.
5. Ophioglossopsids or Ophioglossopsida - modern ferns.
6. Marattiopsida (Marattiopsida) - perennial plants of small and large forms.
7. Polypodiopsids (Polypodiopsida - perennial or, less commonly, annual plants of different sizes). They are divided into three subclasses: Polypodiidae, Marsileidae, Salviniidae.

History of Fern Plant Species

The history of ferns began in the era of dinosaurs - 400 million years ago. In a favorable warm and humid climate of tropical forests, ferns dominated the Earth. Some species reached 30 m in height. Over time, climatic conditions have changed dramatically. How many natural disasters had to happen so that such giants as dinosaurs and tree-like ferns disappeared.

With all the diversity of modern ferns, they are very different from the oldest plants, inferior to them in size and variety of forms. But even today it is the largest group of spores - 300 genera and more than 10 thousand species. Widespread ferns, due to environmental plasticity and amazing features of reproduction.

Prevalence in nature, examples of species

When and where a fern grows depends on the heat and humidity of the area. The habitat of the ubiquitous plants may be:

• lower and upper tiers of forests;
• swamps, rivers and lakes;
• ravines and wet meadows;
• clefts of rocks;
• walls of houses;
• roadsides.

Ostrich

In temperate latitudes, hundreds of grassy representatives of ferns can be found. A brief overview of some species:

1. Orlyak ordinary. Easily recognizable by the leaves in the form of an open umbrella. Distributed in pine forests, suitable for eating.
2. The male thyroid. A herbaceous plant with leaves up to 1.5 m in length, is very rare. Thyroid extract is used in medicine as an anthelmintic.
3. Female coder. Large plant with elegantly shaped leaves.
4. Common ostrich. Large beautiful fern. Due to the long rhizomes, it forms entire thickets. Used in landscaping. Boiled ostrich leaves are edible.
5. Osmund. A plant with a short rhizome and long shiny leaves grows in East Asia and North America.
6. Mnogoryadnik. Its leaves are dark green, arranged in rows.

Suitable for home growing:

• Kostenets;
• Nephrolepis;
• Davallia;
• Asplenium;
• Dixonia;
• Pteris.

These plants admirably decorate the home interior. The Junior variety with corrugated leaves is very beautiful.

Home plant

Interesting Facts:

1. Hecistorteris pumila and azolla cariliniana are the lowest plants. Their length does not exceed 12 mm.
2. Epiphytes feel great on trees and vines.
3. In the mountainous areas you can find Venus hair - an amazing plant with beautiful openwork leaves.
4. Tree trunks of large ferns in the tropics are used as a building material.
5. Marsilea quadrifolia feels great under water.
6. Dicranopteris (Dicranopteris) has leaf stalks of metallic strength.

Rare species of fern-like:

• The thyroid is comb;
• Fegopteris binding;
• Brown Mnogoryadnik;
• Aslenia wall;
• The clusters are divided.
• Salvinia fern floating is listed in the Red Book of Belarus.

How many ferns live

The question "how many years does a fern live" is not an easy one. Life expectancy depends on the place of its growth and species. In temperate latitudes, the terrestrial part of the fern dies with the onset of cold weather, in the tropics it can grow several years. The adnexal roots are replaced every 4 years by new ones; the rhizome itself remains viable for up to 100 years. This feature allows the plant to survive in any conditions.

Features of plant nutrition

Fern-like ones feed on essential nutrients through roots and leaves. The necessary trace elements and water the plant absorbs from the soil. Leaves participate in the process of photosynthesis, converting carbon dioxide into organic acids. So the fern receives starch and sugar, necessary for the vital functions of all organs.

Analysis of the structure of fern plants

The ancestors of fern plants had a primitive structure. In the process of evolution, it has become more complex.

The stalks

The stalk of ferns is underdeveloped, small in size. It is called a rhizome. Of course, tropical ferns with woody trunks are an exception. Curly rhizomes can be forgiven long distances.

Leaves, Vayi

The fern leaf is much more massive than the stem. They are not quite ordinary, they have distinctive features of structure and growth, various forms. More often they are dissected, cirrus. Vayi - the so-called leaves of the fern. The petiole of the leaf is attached to the underground part of the stem - the root or rhizome. Examining them, it is difficult to understand where the stem ends and at what level the leaf begins. An interesting feature of vaya is the growth of the top, which is a curled and gradually unfolding curl in the form of a snail.

Waiy

Leaf development begins in the kidneys underground and lasts up to two years. Only in the third year can they appear above the ground. Due to the apical growth, the waiyas of ferns reach very large sizes.

In most plants, vayas participate in the process of photosynthesis, vegetation, and simultaneously in the formation of spores. Spores appear in soruses, which are located on the underside of leaves in the form of single or group tubercles.

Root system

The root system consists of a powerful rhizome and numerous subordinate roots. The conductive tissue on the stem and roots absorbs water and advances it through the vascular bundles to the leaves.

Reproductive organs

Fern life is divided into two cycles: long asexual - sporophyte and short sexual - gametophyte. The reproductive organs of fern - sporangia, where the spores are located, are located on the bottom of the leaves. Mature spores spill out of bursting sporangia and are carried by the wind far from the mother plant. Some scientists compare spore formation to the flowering of other plants.

Only a fraction of the vast amount of spores survives. The sexual phase begins when the spore grows under favorable conditions into a haploid growth (gametophyte), which looks like a green plate in the form of a heart several millimeters in size. On the underside of the growth, female and male genital organs are formed - anteridia and archegonia. The eggs and spermatozoa formed in them merge in wet weather, and a zygote is formed, from which the embryo of a young plant, sporophyte, develops.

The plant can also propagate vegetatively when brood buds form on the stems and roots. This is important for gardeners who grow some species on their sites.

Comparison with other herbaceous plants

Fern-like - these are ferns, horsetails and crowns. All of them reproduce by spores and have a common origin.

Ferns have characteristic distinguishing features from other herbaceous plants:

1. They differ from algae by rhizome and complex leaves.
2. In mosses and ferns, the generation of gametophyte and sporophyte alternates. Gametesophyte prevails in mosses; sporophyte prevails in ferns. The presence of conductive tissue in the form of vascular bundles makes representatives of fern-shaped plants more adapted to the terrestrial way of life.
3. Unlike flowering plants, they reproduce by spores and do not bloom.

Due to its rich chemical composition, fern has properties that are useful for people. Used for medicinal purposes and in cooking, suitable for salting. Traditional medicine also did not ignore the wonderful plants.