Continuation. See No. 1, 2/2008

General tables on the taxonomy of plants and animals

Test "Higher spore plants"

Option 1 1. Find the extra plant: a) horsetail; b) sphagnum; c) Marchantia; d) cuckoo flax. 2. Have no roots: a) mosses; b) ferns; c) horsetails; d) mosses. a) ferns; b) club mosses; c) mosses; d) horsetails. 4. The gametophyte of ferns is: a) outgrowth; b) protonema; c) ovule; d) dispute. 5. A perennial plant with a rigid, jointed stem, the nodes of which contain whorls of scale-like leaves: a) horsetail; b) clubmoss; c) cuckoo flax; d) fern.

Option 2 1. Find the extra plant: a) clubmoss; b) bracken; c) shieldweed; d) nephrolepis. 2. The leaf grows at the tip of: a) mosses; b) club mosses; c) ferns; d) horsetails. 3. Participates in the formation of peat: a) sphagnum; b) cuckoo flax; c) horsetail; d) clubmoss. 4. Baby powder is obtained from the spores of: a) horsetails; b) club mosses; c) mosses; d) ferns. 5. The horsetail body consists of: a) stem and roots; b) stem and leaves; c) leaves and roots; d) stem, leaves and roots.

Option 1: 1 – a; 2 – a; 3 – in; 4 – a; 5 – a.
Option 2: 1 – a; 2 – in; 3 – a; 4 – b; 5 – g.

Sample, cut cards

Department and class	Representatives	Life form	Structural features	Life cycle features	Meaning in nature and in human life
	Pine ordinary		The leaves are needle-shaped with a waxy cuticle. The wood contains tracheids and many resin passages.	They have special shortened shoots - male and female cones	Needles are vitamin raw materials;
forest-forming species; releases phytoncides B. Class	Cycads		Cycad The leaves are pinnately dissected;	the plant looks like a palm tree	Sperm are motile Core starch – sago –
used for food B. Class	Ginkgo Ginkgo		bilobed	Leaves with a fan-shaped blade on a thin petiole Spermatozoa are motile.	Sporophyte predominates
Ornamental plant, seeds are edible. Relic G. Class Gnetovye	a) Ephedra Ephedra horsetail	(ephedra)	Bush	Scale-like leaves are located opposite	Dicotyledonous embryo
Medicinal plant, ephedrine is obtained for the treatment of allergic diseases	b) Velvichiaceae Velvichia	amazing	Dwarf tree		Rare relict plant, grown in greenhouses
2. Department Angiosperms A. Class Dicotyledons	Rowan ordinary		Seed with two cotyledons, contains a supply of nutrients	Sporophyte predominates	Fruit, medicinal, ornamental plant
	Rose hip cinnamon	(ephedra)	Conducting tissue is formed by vessels and sieve tubes with companion cells	The female gametophyte - the embryo sac - is located in the ovule
forest-forming species; releases phytoncides Monocots	Wheatgrass creeping		The pericarp is fused with the seed coat. Seed with one cotyledon	Double fertilization
	Rye sowing		Has a flower and a fruit with seeds;	the ovule is protected by the ovary	Water is not needed for fertilization, because...

there is a pollen tube

Get bread - the main human food product Conclusion)

Seed plants have vegetative organs - ..., .... The embryo is protected from adverse environmental influences, because

is in... . Fertilization does not depend on the presence of... . Coniferous plants belong to the department... . The most common plants on Earth are .... , ... (

Shoot, roots, seeds, water, Gymnosperms, Angiosperms.

Evaluation criteria

The maximum score is 52: less than 26 – “2”, from 27 to 35 – “3”, from 36 to 48 – “4”, from 49 to 52 – “5” Kingdom of Plants. Higher seed plants

Playing field	Representatives	Life form	Structural features	Life cycle features	Target

: generalization, deepening and consolidation of knowledge about the structural features, reproduction and significance of seed plants

Option 1 1. Department Meaning in nature and in human life Test "Higher seed plants" The main characteristic of angiosperms is the presence of: a) stem and leaves; 2. b) stem, leaves and roots; c) flowers and fruits; d) seed. Seed: a) only protects the embryo from unfavorable environmental factors; b) only provides the embryo with nutrients; c) provides the embryo with nutrients and protects it from unfavorable environmental factors; d) organ of asexual reproduction. a) depends on the presence of water; 4. Find the extra plant: a) horsetail; b) does not depend on the presence of water; c) can occur both in water and without it; d) occurs in the same way as in ferns. 5. b) fir; c) pine; d) spruce. Needles are used: a) as a vitamin supplement;

Option 2 1. b) to obtain resin (resin); c) to obtain turpentine; d) for making paper. Angiosperms include: a) 250 thousand species; b) 500 thousand species; c) 1 million species; d) 1 million 500 thousand species. a) have a seed and a flower; 3. b) have only seed; 4. Find the extra plant: c) have neither seed nor flower; d) have a seed and a fruit. Water is needed for fertilization: a) spruce; 5. b) peas; c) chamomile; d) nightshade. Does not have a flower: a) ginkgo;

Option 1: 1 – in; 2 – in; 3 – b; 4 – a; 5 – a.
Option 2: 1 – a; 2 – b; 3 – in; 4 – a; 5 – a.

Sample, cut cards

Class and family	Representatives	Flower formula	Inflorescence	Fetus	Other Features	Meaning in human life
Class Dicotyledons 1. Rosaceae	Rose hip	*H 5 L 5 T? P?	Single flower	Caenorodium (multi-nut)	Leaves alternate, simple or compound, often with stipules	Ornamental and medicinal plant
		*H 5 L 5 T? P 1	Simple umbrella	drupe	The receptacle is overgrown - convex, concave, saucer-shaped; often involved in fetal formation	Stone fruit crop
2. Cruciferous (Cabbage)		*H 4 L 4 T 2+4 P 1			The petals of the corolla are arranged crosswise	Vegetable and fodder crops
	Shepherd's Purse	*H 4 L 4 T 2+4 P 1		Pod	Leaves are alternate, usually pubescent with hairs	Weed and medicinal plant
3. Nightshades	Potato	*H (5) L (5) T 5 P 1			Leaves without stipules, simple, whole or dissected	Vegetable, fodder and industrial crops
		*H (5) L (5) T 5 P 1	Single flower	Box	Plant parts contain alkaloids	Poisonous and medicinal plant
4. Compositae (Asteraceae)	Sunflower	*H 5 L (5) T (5) P 1 tubular	Basket		Flowers of three types: reed, tubular, funnel-shaped (some have false reeds)	Oilseed crop;
	ornamental plant	Calendula (marigold) 5 L (5) T (5) P 1 H	Basket		reed	Wrapper around the inflorescence
Medicinal and ornamental plant 5. Legumes		Calendula (marigold) (5) L 1+2+(2) T (9)+1 P 1	(Moths)		Single flowers	Leaves are compound with stipules.
		Calendula (marigold) (5) L 1+2+(2) T (9)+1 P 1			Enter into symbiosis with nodule bacteria	Vegetable plant; leguminous crop
Enter into symbiosis with nodule bacteria Fodder, wild plant. Honey plant		Class Monocots 3+3 T 3+3 P 1	Single flower	Box	1. Liliaceae	*ABOUT
		Class Monocots (6) T 6 P 1			They have modified shoots: rhizomes, bulbs	Decorative and protected plant
Leaves are simple, entire, with parallel or arcuate veins Poisonous and medicinal;		ornamental plant 2+(2) T 3 P 1	2. Cereals	(Bluegrass)	ABOUT	Complex ear
	Caryopsis	ornamental plant 2+(2) T 3 P 1	Stem culm with intercalary growth	(Bluegrass)	Main grain crop	Corn

Seed plants have vegetative organs - ..., .... The embryo is protected from adverse environmental influences, because

Cob and panicle

Leaf with vagina

Evaluation criteria

The maximum score is 52: less than 26 – “2”, from 27 to 35 – “3”, from 36 to 48 – “4”, from 49 to 52 – “5” Feed and grain crops

Class and family	Representatives	Flower formula	Inflorescence	Fetus	Other Features	Meaning in human life

there is a pollen tube

The maximum number of points is 98: less than 49 – “2”, from 50 to 67 – “3”, from 68 to 93 – “4”, from 94 to 91 – “5” Fibrous, parallel, arcuate, three, rod, mesh, four, five.)

To be continued

Horsetail is a perennial plant. It overwinters as a rhizome deep in the soil. In early spring, you can see fertile stems of horsetail in fields, along roads, in vegetable gardens, on railway embankments, popularly called pestles.
The stems are not branched, 7-25 cm tall.

Succulent, light brown or reddish-brown in color, the stems of horsetail end at the top with a spore-bearing pistil - a spikelet with spores. After the spores are scattered, the stems die.
After the pistils, leaves later develop in a sterile manner. In horsetail, they are unbranched at the top (branching can rarely be seen on the lower branches), 4-5-sided, without a cavity inside, bright green and very hard. Characteristic are the teeth and stem sheaths: triangular-lanceolate, sharp, black-brown, fused in 2-3 groups. The branches are directed obliquely upward. As my grandmother used to say, she raises branches towards the sun.
Distributed throughout Russia, grows on sandy soil. It is an indicator of acidified soils.
You can go collecting green shoots of horsetail in the summer. Cut them at a height of 5 cm and
When collecting horsetail, it is very important to carefully examine the branches so as not to accidentally take other types of horsetail. They can harm your health. Therefore, in this article I paid a lot of attention to the botanical characteristics of horsetail. The following case was very indicative.
Sometime in 1995, a friend invited me to consult her mother about herbal treatment. The woman suffered from pancreatic cancer in the last stage. My visit was purely psychological in nature: “Please come, just talk, it will make her feel better.” Imagine my surprise when I saw horsetail laid out for drying in the dying woman’s room. Its branches are drooping, twice branched, the stem sheaths have 4-5 brown wide sharp teeth. The woman said that she has been brewing an infusion of such horsetail all her life...
My grandmother taught me to distinguish horsetail as a child: “The branches on the stems of horsetail grow upward towards the sun, and a sick person from illness is pulled towards the sun. And those horsetails whose branches reach down to the ground will put the sick person in the ground.” This image helped me find horsetail not only for me, but also for my daughters, who, by the way, also became pharmacists.
And in the villages they were afraid of hay with horsetails. Horses died from such hay (possibly due to the content of nicotine and saponins).

Horsetail is confused with horsetail. The meadow horsetail does not have branches of the 2nd order, but the branches of the 1st order are long, horizontal, triangular, their whorls are brown, the sheaths of the stems have unfused teeth with a white membranous border.
My grandmother always told me that the most dangerous thing is the marsh (riverine) horsetail: its stem is very thick, there are no branches (or few), there are shallow grooves on the stem and it has a wide cavity.

Chemical composition of horsetail

Horsetail grass contains alkaloids (equisetin, nicotine, 3-methoxypyridine), saponin equisetonin, flavonoids, organic acids (aconitic, malic, oxalic), fatty oil, essential oil, many silicic acid salts soluble in organic compounds, tannins, resins , bitterness, polyoxyanthraquinone compounds, vitamin C, carotene (provitamin A).

Properties of horsetail herb

Horsetail was mentioned in ancient times by Avicenna in his works. Horsetail was used as a unique hemostatic and cleansing agent.
In the Soviet Union, the study of horsetail began in the 40s of the twentieth century. In Russia, the effect of horsetail is still being studied at medical universities: for example, in 2008, the antitoxic, strong diuretic (diuretic), antiexudative, antifungal effect of horsetail extract was proven, and an antispasmodic effect was noted.
Horsetail has:

• astringent,
• hemostatic,
• diuretic,
• anti-inflammatory effect,
• helps remove lead from the body in case of lead poisoning

Animal experiments have shown that horsetail reduces blood sugar levels in diabetes mellitus.
Silicic acid and its salts are very important for most tissues of living organisms: they affect the synthesis of collagen (cartilage tissue) and the formation of bone tissue.
Therefore, an infusion of horsetail herb can be used for pathologies of joints and cartilage tissue, and for spinal hernias.
However, large doses are not recommended to avoid silicosis.

Horsetail grass cannot be used for a long time.

In official medicine, horsetail preparations are used for inflammatory diseases of the urinary tract and kidneys, and in the presence of urolithiasis. It is noteworthy that horsetail is stronger than kidney tea. However, horsetail preparations are contraindicated for nephritis and nephrosonephritis, because may cause kidney irritation.
As a diuretic, an infusion of horsetail herb is used for congestion (edema), heart failure, and pulmonary failure.
Horsetail herb is used in complex preparations for pleurisy and hypertension.
As a hemostatic agent, horsetail herb is used for hemoptysis due to tuberculosis and uterine bleeding.

Horsetail is included in the anti-asthma medicine according to Traskova’s prescription.
An infusion of horsetail herb is used to wash purulent wounds, treat furunculosis, trophic ulcers, hemorrhoidal bleeding (make lotions with a cold infusion).
An infusion of horsetail herb is used as a rinse for tonsillitis, stomatitis, and nosebleeds.

In cosmetology, an infusion of horsetail herb is used for thinning hair, as a mask for acne, and for oily facial skin. In case of baldness, horsetail silicon is deposited near the hair roots and promotes their growth.

Previously, an infusion of horsetail herb was widely used by printers to cleanse the body of lead salts.

Modern pharmacologists recommend horsetail preparations for weight loss, as having a beneficial effect on metabolism, normalizing water-salt balance, removing toxins in the urine, in the form of complex preparations for atherosclerosis, for detoxification in hepatitis, and is widely used externally in cosmetology.

Horsetail preparations:

Liquid extract in cosmetology for skin and hair care
- horsetail is included in the “Fitolysin” paste, which is used internally for kidney diseases
- horsetail herb in the form of infusion, decoction, teas, alcohol tincture, extract, ointment is used in official and folk medicine for various diseases

Most often, horsetail herb is used as part of preparations. Fees are selected individually after consultation with a doctor.

Horsetail decoction
We pour 4 tablespoons of dry horsetail herb with 1 glass of boiling water in an enamel bowl. You need to cook in a water bath from the moment of boiling for 30 minutes, cool for 10 minutes, strain.
Drink 1/3 cup of horsetail decoction 3 times a day, 1 hour after meals. The course is only 3 weeks. Horsetail preparations should not be taken continuously for a long time to avoid silicosis.

Horsetail infusion
2 tablespoons of dry horsetail herb are poured into 0.5 liters of boiling water in a thermos and left for 1 hour. Take 1/2 cup 10 minutes before meals 4 times a day.

Contraindication for the use of horsetail herb is

• pregnancy,
• breastfeeding (lactation),
• severe kidney diseases (nephritis, nephrosis),
• individual intolerance (allergy).

It is important to remember that horsetail contains substances that can cause harm to health if overdosed. Consult your doctor before using horsetail, follow the dosage and course of treatment.

Pharmacist-herbalist Vera Vladimirovna Sorokina

Among the higher spore plants, which include mosses, mosses, ferns and horsetails, the latter have several features in their external and internal structure. The horsetail plant looks like a small Christmas tree with hard side stems. Interestingly, animals do not eat either it or other types of horsetails. This is explained by the fact that plant tissues are impregnated with silicon compounds. The systematic position of the Horsetail genus indicates the fact that their reproduction occurs with the help of spores. Our article will focus on the structure of horsetail, as well as consideration of its use in medical practice as a medicine.

What is alternation of generations?

In the life cycle of a plant, two life forms change cyclically: asexual and sexual generations. The first is represented by a perennial herbaceous plant, the second has the appearance of green plates with a dissected surface with numerous threads. The reproductive organs develop on them: female - archegonia and male - antheridia. The maturation of eggs and sperm, as well as the process of fertilization itself, occurs only in the presence of water. So, to imagine what horsetails are, you must remember that plants exist in two different forms - gametophyte and sporophyte.

External structure

As we said earlier, the asexual generation of horsetail is a plant that has above-ground and underground parts. Thus, the rhizome provides support and promotes vegetative propagation. A large number of adventitious roots extending from it absorb water and minerals from the soil. The rhizome has a large number of thickenings - nodules. It grows deep into the ground. It should be noted that horsetails are indicators of soil acidification. What are soil indicators? These are plants that require a certain concentration of soil solution for normal functioning. In our example, this is an excess amount of hydrogen ions, that is, high acidity of the soil. As it turned out, plants of the Horsetail genus do not live on neutral or alkaline soils, so their favorite places to grow are biocenoses of swampy areas and river floodplains. The most common type of horsetail is horsetail. It is its branches that are harvested as medicinal plant raw materials. Also found are forest horsetail, meadow horsetail (has a triangular stem), and swamp horsetail with a pentagonal stem shape and black edges at the stem nodes. In addition, this species is also highly poisonous.

Vegetative organs

Let's continue to look at the appearance and properties of horsetail. In addition to the rhizome, the vegetative parts of the plant body include stems, leaves and sporangia. They form a sporophyte - an asexual generation, whose task is to carry out the process of photosynthesis and the formation of reproductive organs - spore-bearing spikelets. The main ground shoot grows from the rhizome; it branches and is divided by nodes, from which lateral branches diverge in the form of a whorl. There are no leaves with a clearly defined leaf blade; they are reduced to colorless scales that grow from the nodes. Therefore, the function of photosynthesis in horsetails is performed by stems containing chlorophyll. Let's continue to study higher spore plants - horsetails. What are spring and summer forms of shoots? It turns out that the axial organ of the plant is ribbed, impregnated with silicon compounds and has a clear differentiation. Thus, spring shoots are light pink in color, incapable of branching and devoid of green pigment and leaves. At their tops sporangia are formed in the form of hard shields resembling spikelets containing haploid spores. Summer shoots are the main and subsidiary stems, which are bright green. They are capable of branching and, thanks to chlorophyll, carry out the synthesis of organic substances: proteins, carbohydrates and fats, and also provide the release of oxygen.

Sporangia and spores

Like other representatives of higher spore plants - mosses, mosses and ferns, horsetails develop organs on the sporophyte plant in which the maturation of asexual reproduction cells - haploid spores - occurs. Spikelets - sporangia of horsetails, have the form of special structures collected together, called sporangiophores. They are derivatives of lateral stems and look like rings, closely pressed to each other. Spores are formed through the process of meiosis and are haploid cells of the same type. Therefore, the question of what horsetails are from the point of view of the structure of their asexual generation - the sporophyte - can be answered as follows: these are homosporous plants. In addition, the spores are equipped with special springs - elaters, which serve as a device for their better distribution. Subsequently, once on moist soil, the spores germinate and unisexual shoots appear, on which male or female genital organs develop separately.

Gametophyte and fertilization process

Haploid spore cells under favorable environmental conditions (sufficient humidity and absence of direct sunlight) begin to form green lamellar structures with filamentous processes along the edges. This is how a growth is formed. Which genital organs, male or female, will form on it will depend on the light and ambient temperature. On the underside of the shoot there are rhizoids that attach it to the soil surface. Antheridia are male reproductive organs that ensure the development of sperm, and archegonia contain eggs. Fertilization occurs in the presence of water. From the resulting zygote, an embryo develops, which subsequently gives rise to the development of the sporophyte - an asexual generation of horsetail, the medicinal properties of which have been known to man for quite a long time. Next we will look at them in more detail.

Application in medicine

One of the most common species, horsetail, is an effective diuretic and hemostatic herbal preparation obtained from the stems. If the functioning of the kidneys and heart is impaired, accompanied by fluid retention in the tissues and the appearance of severe edema, use a decoction prepared in the proportion: 20 g of raw material per 200 g of water. The diuretic effect is explained by the presence of saponin in horsetail shoots and the high content of potassium ions. In addition to them, plant materials contain vitamin C, carotene, equisetrin, calcium and iron ions. Horsetail decoction is used for uterine bleeding, in the treatment of pleurisy, and for inflammatory processes in the ureters and bladder. Pharmacological raw materials can be purchased in pharmacies in the form of an extract, brewing bags or briquettes.

Horsetail: properties and contraindications

The presence in the vegetative parts of horsetail of a large number of microelements, for example, copper, boron, molybdenum, has a positive effect on metabolism in the human body. However, the high concentration of alkaloids, glycosides and saponin determines not only the astringent, anti-inflammatory and diuretic properties of the plant, but can also cause a number of negative symptoms. For example: diarrhea, nausea, heaviness and pain in the epigastric region. Horsetail extract should be used with caution in the treatment of patients with gastric and duodenal ulcers. A prerequisite for taking medications is not only a strict dosage - no more than half a glass, but also the frequency of use (no more than 3 times a day), as well as compliance with the main rule - using a decoction or extract an hour after meals.

The role of horsetails in ecosystems

What is the significance of horsetails in nature? Giant extinct species of tree-like higher spore plants: horsetails, mosses and ferns, which lived in the Carboniferous period of the Paleozoic era, caused the formation of coal reserves in the bowels of the earth. Modern species of plants of the genus Horsetails are much smaller and distributed in different climatic zones, especially in floodplain meadows and swamps, as well as in coniferous forests. As we said earlier, horsetails thrive on acidic soils; many species, for example, horsetail, clog crops and pastures for domestic animals, since they are inedible for them. In everyday life, the hard branches of horsetail, containing silicic acid and its salts, were previously used as an abrasive for cleaning heavily soiled kitchen utensils.

In our article we examined the properties, structure and significance of horsetails in nature and human life.

The Latin name Equisetum was first used for one horsetail by the ancient Roman naturalist Pliny the Elder, obviously referring to the similarity of the branched shoots of horsetail with the tail of a horse (from the Latin equius - horse and saeta, seta - bristles, coarse hair). The similarity of an adult plant with a tuft of hair and a tail is reflected in the most widespread Russian name (horsetail) and in the names in many Slavic languages. In some areas of our country, horsetails with whorled branches were also called “Christmas tree” or “pine tree,” and because of the presence of brown spore-bearing shoots similar to a pestle in some species, they were called pistils or pushers. In nature, horsetails are usually found in the form of clones (groups of plants that arose through vegetative propagation from a single specimen), which often occupy areas of several tens or even hundreds of square meters.

The size of the stem of horsetails varies greatly not only among different species, but even within one fairly extensive clone, depending on environmental conditions. Among horsetails there are also small, dwarf plants with a stem 5-15 cm high and a diameter of 0.5-1 mm ( horsetail- Equisetum scirpoides) and plants with stems several meters long. Yes, y horsetail polychaete(E. myriochaetum) the stem reaches a length of 9 m, but due to its small thickness (0.5-2 cm), such a long stem cannot independently remain in an upright position and is forced to rely on neighboring plants. The stems of most common horsetail species in the temperate zone rarely exceed a height of 1 m; tropical species usually have longer stems.

According to the nature of aboveground shoots, or more precisely, according to their consistency and functional morphology, horsetail species can be divided into two groups.

In some species, all aboveground shoots are of the same type. They are very tough, usually evergreen (that is, they live for more than one season and overwinter in the temperate zone) and develop apical strobili (Table 17). Species of the second group have two types of shoots - some are spore-bearing, brownish or green, and others are vegetative, green. Shoots of both types appear in the spring above the soil surface; they are more tender in consistency than shoots of the species of the first group, and die off by winter. The development of vegetative and spore-bearing shoots in species of the second group proceeds differently. For example, at horsetail (E. arvense) spore-bearing shoots appear first (in early spring). They are brownish-pink, unbranched, usually thicker than the rapidly greening vegetative shoots, and after sporulation they mostly die off. U horsetail (E. sylvaticum) and meadow (E. pratense) spore-bearing shoots with well-developed strobili appear in early spring simultaneously with vegetative ones. Both start out pale pink and then turn green. After sporulation (and the strobile dries out), the spore-bearing shoots function similarly to vegetative shoots (Table 17). Finally, in species such as horsetail (E. palustre), horsetail (E. fluviatile) and horsetail bogota

At the end of the growing vegetative shoot of horsetail, under the protection of young leaf sheaths, there is an apical cell shaped like a triangular pyramid. The apical cell sequentially separates segments along three sides, and as a result of the divisions of these segments, ring-shaped sheath primordia appear on the stem. Two to four layers of cells in the lower part of the ring-shaped primordium retain their ability to divide for a very long time, forming a zone of intercalary, or intercalary, meristem, covered from the outside by a leaf sheath below the located node (if you pull the top of a growing horsetail stem, the rupture occurs right along the zone intercalary meristem). As a result of elongation of the derivatives of the intercalary meristem, the horsetail stem grows in length. Cells of the intercalary meristem located above any node eventually lose their ability to divide and differentiate into permanent tissues (this is why mature horsetail stems that have stopped growing are more difficult to break than young ones).

On the surface of the horsetail stem in the area of ​​the internode, ridges and valleys are visible, usually alternating with ridges and valleys above and below the located internodes. The number of ridges is usually related to the diameter of the stem. On a cross section of an internode of a mature photosynthetic stem, the epidermis, cortex, vascular bundles and central cavity are visible (Fig. 78).

The eciderma of the internode consists of tightly closed cells with sinuous adjacent walls. The outer shell of these cells is greatly thickened and covered on the outside with balls, rods, papillae, ridges and other sculptured formations of various sizes (Fig. 79).

The cell membrane of the epidermis and, to a lesser extent, other shoot tissues contains silica along with cellulose. Silica particles are located in the cell membrane between the cellulose strands, and on the surface of the epidermal cells they form a continuous and homogeneous, very strong layer with small tubercles confined to the outgrowths of the membrane. The silica layer, in turn, is covered on the outside with a thin cuticle with a waxy coating and plays not only a mechanical, but, apparently, a protective role, since horsetails are practically not attacked by various herbivorous mollusks and insects.

The stomata in the internodes are confined to those areas of the epidermis that line the hollows. In some species of horsetail, the stomata on each slope of the hollow are located in a narrow strip, in 1-4 clear longitudinal rows, and are sunk to the bottom of a funnel-shaped chamber, sometimes common to several stomata; in other species, the stomatal stripes on the slopes or bottom of the hollows are wider, without clearly defined longitudinal rows of stomata, and the secondary cells of the stomatal apparatus are located at the level of the remaining cells of the epidermis (Fig. 79, middle). The number of stomata on the surface of the stem is very large. So, for example, in one stomatal row the internodes wintering horsetail(E. hyemale) have about 400 stomata; on the surface of one internode there may already be about 15 thousand stomata, and on the surface of a stem only about half a meter high - more than 300 thousand stomata.

The stomatal apparatus of horsetails consists of four cells arranged in pairs “in two layers” - two side cells lie on top and cover two guard cells (Fig. 78). All four cells arise from one mother cell. On the inner surface of the side cell wall that borders the trailing one, there are comb-like thickenings. The outer wall of the side cell is smooth on the outside or covered with silica balls, and has an arch-like thickening on the inside. Side cells can tightly close the stomatal fissure due to the presence of a locking mechanism. In some species of horsetail, this mechanism is built according to the ridge-groove principle (Fig. 78), and in others, according to the principle of a “zipper” lock (silicon pimples or rods, located in one to three rows along the edge of one side cell, fit into the spaces between pimples or rods located along the edge of another cell, and vice versa, see Fig. 79, table 16).

, ,

The primary cortex lying under the epidermis in its peripheral part consists of sections of mechanical and photosynthetic tissue. The relative location, size and outline of these areas on the cross section of the internode are different in different species (Fig. 80), but always under the protrusions of the stem, i.e. in the ridges, carinal cords of mechanical tissue are located. The mechanical tissue is composed of narrow and long (up to 0.5-1.5 mm) living cells elongated along the stem. The membrane of mature cells contains a large amount of silica, so the strands of mechanical tissue together with the epidermis constitute the main mechanical support of the aboveground stem of horsetail.

Photosynthetic tissue, or chlorenchyma of the stem (the usual photosynthetic organs, leaves, are reduced in horsetails and this function is performed by the stem), primarily underlies those parts of the epidermis in which the stomata are located, but chlorenchyma can also be located under the ridges or located in a continuous ring.

The inner part of the primary cortex consists of the main parenchyma of thin-walled, loosely arranged round cells. In it, under the hollows, there are vallecular, or hollow, cavities, filled at the beginning of their development with water and then with air.

The zone of vascular bundles in the internode is delimited from the surrounding tissues by one or two rings of single-layer endoderm, or each bundle is surrounded by endoderm (Fig. 80).

,

The conductive system of the horsetail is represented by the arthrostele. On a cross section of the internode, under the ridges, closed (i.e., without cambium) collateral bundles with carinal canals (from the Latin carina - keel, here: stem ridge) conducting water are visible (Fig. 78). The channel arises due to the dissolution of some conducting elements of the xylem and the divergence of the parenchyma cells surrounding these elements. Usually, at the inner edge of the carinal canal, slightly protruding into its cavity, the annular tracheids of the carinal protoxylem are located. There are very few of them, and each tracheid can be equal in length to an internode. The tracheids of the carinal metaxylem adjoin the canal near its outer edge; the lignified rings of the secondary shell in them are often connected by bridges.

Outside the canal there is phloem, on the sides of which there are usually groups of lateral, or lateral, xylem. Sometimes, due to a strong elongation of the internode, some protoxylem elements of the lateral groups are destroyed, and in their place cavities or lacunae are formed, often almost the same diameter as the carinal canal. Through these gaps, as well as through the channel, there is an upward flow of water with substances dissolved in it. By the presence of three independent centers of xylem origin (carinal and two lateral), the vascular bundle of horsetail differs sharply from the bundles of other plants.

Phloem in horsetails consists of sieve elements and parenchyma cells. Sieve elements are narrow and long (sometimes up to 3 mm) cells with small sieve fields on the longitudinal and terminal walls. In most horsetails, the parenchyma cells in the center of the internode diverge as the stem grows. In this case, a cavity is formed, initially filled with water and subsequently with air. This cavity, together with the hollow cavities, plays an important role in the gas exchange of a mature plant with the environment.

The vascular bundle of the internode in the middle part of the stem, approaching the higher node, is divided into three branches, of which the middle one deviates outward and becomes a bundle going into the leaf (i.e., a leaf trail) (Fig. 81). The lateral branches, merging with the lateral branches of neighboring bundles, form so-called synthetic bundles, passing further into the next internode.

On the transverse and longitudinal sections of the vegetative stem in the area of ​​the node (Fig. 81), it is clear that the hollow and central cavities of adjacent internodes are separated by partitions, and the conducting system, after the departure of leaf traces, has the form of a short tube, or siphonostele. Leaf breaks in the stele do not form when leaf traces depart.

At the nodes, compared to the internodes, the volume of metaxylem increases greatly, which here consists of very short or almost isodiametric reticulate or porous tracheids with simple or bordered round pores (Fig. 82). The xylem of the node in horsetails also includes peculiar vessels, usually consisting of two segments.

In the diaphragms (partitions) between the central cavities of adjacent internodes in a young stem there are holes through which air can pass from one central cavity of the stem to another.

Leaf sheaths, covering the base of each internode (Fig. 83) and protecting the zones of the intercalary meristem, in their internal structure are close to the peripheral part of the underlying internodes, and the ridges and stomatal rows of these internodes continue the ridges and stomatal rows of the sheaths and can be traced further in the leaf blades. The epidermis of the inner surface of the vagina adjacent to the stem in most species usually does not have normal (ventilating) stomata.

Along the upper edge of the vagina there are serrated leaf blades, which in the bud are fused with each other and form a cap covering the top of the stem with younger leaf primordia. Subsequently, as the stem grows in length and thickness, the leaf blades move away from each other, but sometimes the rupture does not occur along all fusion lines, so the number of teeth along the edge of the sheath may not correspond to the actual number of leaves.

The toothed leaf blades are usually short and contain very little chlorenchyma. The shape of the vagina, color, shape and lifespan of the teeth are different in different species (Fig. 83), which is used in identifying horsetails. On the inner surface of the plate, and sometimes the vagina, facing the stem, there is a structure that secretes droplet liquid water and is called a hydathode. From the surface it looks like a light area of ​​the leaf on which water stomata are located.

,

Water stomata differ from ordinary (ventilation) ones both in their location and structure (Table 16). They are open, located above the vascular bundle, and the secondary cells of the stomatal apparatus always lie at the level of the remaining cells of the epidermis. Guard cells lack chloroplasts and have evenly thickened membranes. Under the epidermis in the hydathode region there is not photosynthetic tissue, as under ordinary stomata, but a special thin-walled parenchyma tissue covering the vein. Water entering through the tracheids of the vein passes through this tissue to the water stomata and is released out. The release of droplet-liquid water, or guttation, can be observed in horsetails of the taiga zone from late evening to early morning in summer in clear weather, when the amount of water pumped by the roots from the warm soil heated up during the day exceeds the amount of water evaporated by the shoot. Drops of water at this time are clearly visible along the edge of the vagina, especially the vagina of the last nodes (Table 17).

The stem of horsetails branches monopodially. The primordia of the lateral branches (buds) are initially covered by the bases of the leaf sheaths, but during their further development they break through them (Fig. 81, 83). Some primordia remain dormant, so that nodes with and without branches can be found on one shoot. In the same way, within one clone you can find shoots with and without branches. It is usually believed that horsetails differ sharply from other higher plants in a special type of formation of lateral branches, the rudiments of which do not arise in the axils of the leaves, but alternate with the leaves. However, the branches of horsetail can be considered axillary, if we assume that in the process of evolution, most of the leaf blade, in the axil of which the branch is formed, has grown along the entire internode to the stem (Fig. 81). Then the tip of the leaf, “parent” in relation to any branch, should be sought not at the same node from which this branch departs, but at a higher adjacent node. Assuming the growth of the leaf to the stem, it is easy to explain the presence of three groups of xylem in the internode bundle of the horsetail.

,

A root rudiment forms at the base of the lateral bud. The study of bud development shows that the bud and the root originate from a single mother cell, the division of which produces a more or less spherical mass of cells. The shoot differentiates in the upper part of the cell mass, and the root differentiates in the lower part. The root primordia of above-ground shoots usually do not germinate, but if the shoot is sprinkled with earth or immersed in water, roots will grow from the root primordia at its nodes, although some buds will remain dormant.

Of particular importance in the regeneration of above-ground shoots and in the vegetative propagation of horsetails are the dormant buds of those stem nodes that are located underground near its surface.

In horsetails, which are characterized by shoot dimorphism, some features are observed in the structure of the stems of spore-bearing shoots. Thus, the stems of spore-bearing shoots of horsetail at the beginning of sporulation resemble in their structure the non-green stems of vegetative shoots that are just beginning to emerge from the ground; they are round in cross section, contain a tiny amount of silica, do not have hollow cavities, chlorenchyma and stomata (stomata are present only on leaf sheaths), and under the epidermis they have a continuous ring of tissue, the cells of which can be considered as mechanical cells in the first stages of ontogenesis skaya tissue characteristic of mature vegetative shoots. As the spore-bearing shoots mature, their structure undergoes minor changes; For example, hollow cavities appear in them. But usually, chlorenchyma and well-developed mechanical tissue, so characteristic of a mature vegetative stem, do not appear in a spore-bearing shoot.

As already noted, horsetails are perennial rhizomatous plants. Their rhizomes are located in the soil at different depths, and the size of the rhizomes varies among different species and among plants of the same species. Horsetails have two types of rhizomes - horizontal and vertical. Horizontal rhizomes are usually thicker, with longer internodes; vertical - thinner and with shorter internodes (Fig. 84). For example, in horsetail, the thickness of the horizontal rhizome is 5-10 mm with a length of internodes up to 25 cm, and the thickness of the vertical one is 1-3 mm with a length of internodes up to 10 cm. With the help of branching horizontal rhizomes, often located at a depth of up to 0.5- 2 m, the horsetail seems to capture new territories, and with the help of vertical ones, it masters them. It is the horizontal ones that should be considered true rhizomes - these are the organs of vegetative propagation. Vertical rhizomes are, in fact, slightly modified underground bases of above-ground shoots extending from horizontal rhizomes.

The surface of the internodes of the rhizomes is matte or shiny, compared to the surface of the above-ground internodes of vegetative shoots, it is smoother, the ridges are less pronounced or completely absent, the color of the rhizomes varies from light yellow or pinkish to almost black. As on aboveground stems, there are leaf sheaths on the rhizomes, but here they (and often the surface of the internode) are often covered with hairs. Young hairs secrete mucus, which apparently protects young shoots and buds from drying out. Over time, the membranes of the hairs, like other epidermal cells, become saturated with fat-like substances and become impermeable to water and gases. Thus, the evaporation of water from the surface of the rhizome is sharply reduced.

Rhizomes do not have stomata, chlorenchyma, or strands of mechanical tissue of the type found in aboveground vegetative stems. Under the epidermis of the internodes of the rhizome lie one to five layers of more or less thick-walled, not lignified, but impregnated with fat-like substances and silica, parenchyma cells, under which, in turn, lie thin-walled cells of the main parenchyma containing starch grains. The amount of starch in the cells depends on the season of the year and the location of a given section of the rhizome. For example, in horsetail, the amount of starch in the rhizome decreases at the beginning of summer (due to the development of above-ground shoots), then increases in mid-summer (when above-ground shoots are actively photosynthesizing) and falls again by autumn (due to the formation of the primordia of next year's shoots).

As on above-ground stems, on rhizomes, under the protection of leaf sheaths, the primordia of shoots and roots are formed, but, unlike above-ground stems, most of the buds on the rhizomes usually remain dormant, and the root primordia at the base of these buds sprout and pierce the sheaths, so that the nodes of the rhizome They are carried not by whorls of branches, but by whorls of roots (Fig. 84).

Some lateral buds on both horizontal and vertical rhizomes, germinating, form a tuber, which is a strongly thickened and modified shortened internode of the branch. Sometimes a chain of such tubers is formed - adjacent internodes of one branch (Fig. 84). The size of the tubers varies among different species; the largest tubers (30 x 25 mm) are apparently characteristic of horsetail(E. telmateia). The tuber parenchyma cells are very large and literally filled with starch grains.

In horsetails, there are two types of roots: roots with positive geotropism, i.e., growing downward, in the direction of gravity, and ageotropic roots, i.e., not responding to gravity. Positively geotropical roots are thick, 1 - 5 mm in diameter. They usually extend one at a time from the nodes of the rhizome and often reach a length of 0.5-2 m, so that the suction zone of the roots is located in watered soil horizons, even in species living in dry places. Ageotropical roots are thin, hair-like, less than 1 mm in diameter; they are located in whorls on the nodes of the rhizome, and usually do not exceed 10 cm in length. The roots of horsetails have air cavities and vessels, the segments of which have a simple perforation plate (Fig. 85). Water is quickly supplied through vessels from deep soil horizons to rhizomes and above-ground shoots.

Vegetative propagation of horsetails is carried out primarily using rhizomes. Old sections of rhizomes die off, and the initially single maternal clone breaks up into several derivatives.

Horsetail strobili usually appear at the ends of stems, less often on lateral branches. The number of strobili on one shoot varies from one (in most species) to hundreds (in polychaete horsetail). The strobili are more or less ellipsoidal, from 2 to 80 mm in length, from yellowish to brown or almost black, blunt or sharp (Fig. 86). At the base of the strobilus there is a collar, which is a reduced leaf sheath, and on the strobilus axis, sporangiophores are located in whorls in the form of hexagonal (usually) scutes on legs.

On the inner side of the scutellum there are 4-16 sporangia elongated along the stalk.

Horsetail sporangium develops from a group of superficial cells: one larger one (axial cell) and several smaller ones. Each of these cells is divided by a septum running parallel to the surface of the sporangiophore. Sporogenic tissue is then formed from the internal cells, and sporogenic tissue and multilayered sporangium are formed from the external cells. Cells adjacent to the sporogenous tissue subsequently differentiate into a lining layer, or tapetum. The membranes of the tapetum cells and some snorogenic cells blur, and a mass of cytoplasm with nuclei, or periplasmodium, is formed, which is used to feed the developing spores. Most sporogenic cells, dividing mitotically, give rise to spore mother cells, or sporocytes, each of which, after meiosis, forms a tetrad of spores. In horsetails living in the temperate zone, meiosis in sporangia occurs in the summer, or at the end of the growth period, and sporulation occurs in the same summer or in the spring of the next year. Many horsetails of the tropical zone do not have periodicity in the formation of strobili and the timing of meiosis to any season of the year, so that on one shoot one can find strobili at different stages of development.

Horsetail spores are spheroidal, 30-80 microns in diameter, and in each species the spore size is more or less constant. In the cytoplasm of the spores there is a large nucleus, around which numerous chloroplasts with starch granules are evenly distributed. From the outer layer of the spore shell, when it matures, hygroscopic ribbons - elaters - spirally wrapped around the spore body emerge (Fig. 87).

As the spores mature, the strobilus axis is slightly extended, the sporangiophore shields move away from one another, and the sporangia quickly dry out. By this point, the inner layers of the sporangium wall have already collapsed, and only one outer layer remains, called the exothecium, when the cells of which dry out, the sporangium wall bursts with a longitudinal slit. The opening of the sporangium is facilitated by the increasing pressure of the spore mass on the wall of the sporangium from the inside due to the expansion and twisting of the elater as it dries. After opening the sporangium, the elaters unfold even more, loosening the mass of spores and at the same time linking them to each other, so that ultimately the contents of the sporangium emerging through the gap in the wall take the form of a grayish-green loose powder, lumps of which are easily blown away by the wind and are transported over considerable distances. Horsetail spores quickly die in the external environment and germinate only those that, shortly after falling from the sporangium, fall onto a shaded, moist soil surface or into water. Once in favorable conditions, spores germinate very quickly. In this case, the spore swells greatly, the so-called middle, in fact the second, counting from the outside, layer of the spore shell bursts and is shed (the first layer - elaters - in nature is often shed even earlier, when wind-borne spores hit some obstacle or at the moment sudden hygroscopic movements).

From the spore, after the first division, a positively geotropic rhizoid and a growth cell (gametophyte cell) are formed, which divides repeatedly and gives rise to a green gametophyte (Fig. 88). In low light or in dense crops, the gametophyte looks like a single-row green thread - chloronema. With sufficient lighting, the filamentous stage in the development of the gametophyte is usually not expressed, and it immediately takes the form of a single-layer plate growing with the help of the apical meristem. Some cells of the lamellar gametophyte give rise to secondary rhizoids. After some time, the two-dimensional lamellar gametophyte turns into a three-dimensional gametophyte with a more or less massive basal part, the cushion, spread across the substrate. On the upper side of the cushion, erect green plates up to 1-4 mm long develop, and on the lower side there are colorless, up to 1 cm long rhizoids that attach the gametophyte to the soil and suck water and mineral salts from it. Under good lighting and nutrition conditions, a meristem soon differentiates along the edge of the cushion, as a result of which both the volume of the cushion and the number of plates and rhizoids increase.

When germinating single spores on a sterile nutrient medium, it was possible to find out that horsetails have three types of gametophytes: male, female and bisexual, differing in growth rate, development rate and morphology. The size of male gametophytes in horsetails varies in diameter from 1 to 10 mm, female gametophytes - from 3 to 30 mm. In the same species, under equal cultural conditions, male gametophytes are smaller than female gametophytes. The first antheridia appear on male gametophytes, depending on the type of horsetail, 20 - 110 days after sowing the spores, and the first archegonia on female gametophytes - after 30 - 130 days.

During the formation of the male gametophyte, the marginal meristem forms a small number of plates, and then gives rise to an antheridial branch - a blade sharply curved upward, on the lower side of which antheridia appear along the edge.

In gametophytes found in nature, the number of antheridia is usually small. In culture, old gametophytes can have several branches with tens or hundreds of antheridia. Antheridia can also appear at the tips of the plates, and sometimes the plates germinate and give rise to a more or less massive body with a marginal meristem. This marginal meristem can either give rise to new male branches with their own meristem, or, in a few species, a cushion with plates and archegonia is formed from it, and thus the initially male gametophyte turns into a bisexual one.

During the formation of the female gametophyte, the marginal meristem usually does not stop its activity of forming a cushion, plates and rhizoids, but when the cushion reaches a certain size, archegonia arise from some cells of the meristem. Mature archegonia are located at the base of the plates. In unbranched gametophytes, after some time, the meristem along the entire edge of the cushion begins to form antheridia. If the gametophytes are branched, then the marginal meristem of only some branches is degenerated and gives rise to antheridial branches with antheridia, at the base of which the antheridial meristem then arises. Thus, the initially female gametophyte turns into a bisexual one, bearing both archegonia and antheridia. Gradually, all branches of the female gametophyte degenerate into antheridial ones, and after the death of the archegonia, the gametophyte becomes functionally male.

In culture, the number of archegonia on one gametophyte varies from 20 to several hundred; in gametophytes found in nature, the number of archegonia is often much smaller.

It should be noted that female gametophytes of all horsetail species can become bisexual, and this contrasts sharply with the inability of male gametophytes of the vast majority of members of this genus to form archegonia.

Horsetail gametophytes are very sensitive to environmental conditions. In experiments with strictly controlled and constant environmental factors, one can often notice differences in the morphology of gametophytes of different species and subgenera. In gametophytes grown in nature, it is difficult or impossible to notice species differences, and wild gametophytes themselves sometimes differ very sharply from cultivated ones in the size of the cushion, the number and length of lobes and plates, the speed of development, the number of gametangia, etc. In nature gametophytes may not have time to begin forming gametangia of the other sex before the onset of unfavorable weather, and the population will thus consist of only male and female gametophytes.

Typically, the number of male gametophytes in a population varies greatly (from 3 to 100%) depending on both the horsetail species and various environmental conditions. In general, conditions that favor the growth of young gametophytes lead to the formation of more female gametophytes, while unfavorable growth conditions produce more male gametophytes. More male gametophytes arise from spores stored for a long time, which have low germination energy, than under the same conditions from freshly collected spores.

Mature antheridia of different types of horsetail differ from each other in the shape of the cavity in which the spermatocytes lie, the degree of their elevation above the surface of the gametophyte, the number, shape and location of the cells of the operculum.

Horsetails have large and very complex spermatozoa. The locomotor (motor) apparatus of the sperm consists of a spirally twisted supporting body, or blepharoplast, with numerous (about a hundred) flagella directed backwards and to the side in the living sperm. Each flagellum bends in a wave-like manner and describes a conical surface in space (Fig. 88). The duration of sperm swimming, the direction and nature of their movement (wave length and amplitude) depend on the composition and temperature of the water.

A mature archegonium consists of an abdomen immersed in the tissue of the gametophyte and a three- or four-tiered neck protruding above its surface. In the abdomen there is an egg cell, above which lie a peritoneal tubular cell and two cervical tubular cells (Fig. 88).

Fertilization in horsetails occurs only in the presence of droplet-liquid water on the surface of the gametophyte (during heavy dew or rain). The mucus protruding from the neck of the archegonium swells in water and releases substances into it that attract sperm, which swim up to the neck and penetrate its canal, but only one of the sperm fuses with the egg.

As a result of fertilization, a zygote is formed, which immediately, germinating, gives rise to a pre-embryo sporophyte, which later develops into an embryo. The horsetail embryo absorbs food from the gametophyte cells at the base of the first leaf sheath.

The seedling emerging from the embryo is usually small. Its height only occasionally exceeds 10 cm. The stem of the seedling bears 10-15 leaf sheaths with three leaf teeth each. A bud forms at the lower node of the primary shoot, which gives rise to the next, more powerful shoot with its own root and leaves, usually collected in a whorl of four. At the base of the second shoot, a more powerful third shoot then appears, etc. The first internodes of the third and subsequent shoots usually bend down and go deeper into the soil, forming a descending rhizome, which then becomes horizontal. Ultimately, a system of underground branched rhizomes and above-ground shoots is formed.

All horsetail species that have been studied cytologically so far have the same chromosomal number - n=108. Such a high and stable chromosome number within the genus was, in all likelihood, established a very long time ago.

Horsetails are characterized by very high morphological plasticity. For example, horsetail, which has recently settled in a well-lit area with disturbed vegetation, usually has low, prostrate stems, but later, when the surrounding vegetation develops, powerful upright stems with branched branches may emerge from more mature rhizomes of the same clone. When approaching the northern borders of the range of the same species, spore-bearing shoots, brownish in plants of the temperate zone, are replaced by green, and then branched green spore-bearing shoots of tundra plants. Shoots of other species are also very variable. These modifications, arising under the influence of various environmental factors and often within the same clone, were and are, along with numerous hybrids and inherited deformities, one of the reasons for disagreements in assessing the size of the genus.

Most modern taxonomists believe that horsetail genus(Equisetum) is small in volume and includes about 20 extremely polymorphic species, grouped into two subgenera - equisetum(Equisetum) and hippochaete(Hippochaete). Some researchers consider it advisable to distinguish these subgenera into independent genera. Among the species already mentioned in the text, the subgenus equisetum includes horsetails Bogota, marsh, large, forest, meadow, field, riverside; to the subgenus hippochaete - horsetails branched, wintering, reed, polychaete.

Horsetails are quite widespread on Earth. However, the southern hemisphere is much poorer in them than the northern. There are no native species of horsetails in Australia, New Zealand or tropical Africa. The tropics are predominantly inhabited by species from subgenus hippochaete, and from subgenus equisetum only two - Bogota horsetails(in Central and South America) and spreading- E. diffusum (on the Hindustan Peninsula). Horsetails of the subgenus equisetum are inhabitants mainly of the temperate and arctic zones of the northern hemisphere.

Horsetails have characteristics of both hygrophytes (weak development of the water-conducting system and well-developed aerial tissue) and xerophytes (stomal guard cells submerged under the surface of the epidermis, closed stomata on old sections of the stem, highly developed mechanical tissue, photosynthetic stems, reduction of leaves). In some species of horsetail (for example, riverine horsetail), the characteristics of hygrophytes come to the fore; in others (for example, in horsetail) - xerophytes; still others (for example, horsetail) can be classified as mesophytes - plants that live in places with an average degree of soil moisture; the fourth are more correctly characterized as hygromesophytes (for example, horsetail) or xeromesophytes (for example, horsetail). Some horsetails (such as horsetail) can live in cold, damp soil and are psychrophytes. Often one species of horsetail has a wide ecological amplitude; for example, horsetail behaves like a psychromesophyte in some places, and like a hygrophyte in others.

Horsetails can be found in different plant zones and communities, but in any case near water or in places with sufficient moisture content in the soil or with a relatively shallow groundwater table. In extreme conditions of existence, horsetails apparently reproduce exclusively vegetatively.

Being part of pioneer plant groups and occupying areas with disturbed natural vegetation, horsetails often form pure or almost pure thickets in places where other plants cannot live, for example, due to the abundance of water or, conversely, due to its lack in those layers of soil where the root system of these plants is located. Once settled in any territory, horsetails, thanks to the presence of deep-lying rhizomes, the mass of which exceeds the mass of the above-ground parts of the plant several times, successfully resist such adverse environmental influences as droughts, forest fires, etc., and successfully compete with others plants, holding the captured territory for a long time.

Settling in areas with disturbed vegetation, horsetails are widespread and difficult to eradicate weeds of pastures and fields, especially newly developed fields with acidic soils that have recently emerged from under a forest or meadow.

Among the species of the subgenus equisetum there are plants that are poisonous to livestock, but information about their toxicity is quite contradictory. Swamp, field and riverine horsetails are usually listed as dangerous species for horses; when found in large quantities in the hay, they can cause the disease equisetosis, which was known in Russia under the name “shatuna” or “drunken disease.” Poisoning of cattle in Europe and North America is usually associated with marsh horsetail, and less commonly with riverine and field horsetails. When eating hay with a large number of these species (cows usually do not take fresh plants into their mouths on pastures), rapid emaciation of animals, a drop in milk yield and milk fat content are observed. Ultimately, if the horsetail-contaminated feed is not replaced, animals may die from exhaustion. When sheep eat horsetail, they experience emaciation and cessation of wool growth.

The toxic principle in horsetails, which causes chronic poisoning of animals, is akin to thiaminase, an enzyme that destroys vitamin B1. Cases of acute poisoning of animals are apparently associated with the presence of saponins (equisetonin) and flavone glycosides in horsetails, the amount of which in the plant varies depending on the habitat, time of year and many other conditions, and this may explain the contradictory information about toxicity of one species or another for different animals in different areas.

There is much less information about the toxicity of horsetails from the subgenus Hippochaete to livestock. Moreover, experimentally and reliable observations in nature have confirmed the high feeding value of many species of this subgenus for horses, cows, reindeer, sika deer, and wild boars. But it should be noted that wild and domestic animals (with free grazing) use horsetails of the subgenus Hippochetes for food mainly after the onset of severe frosts in the fall and then in winter, as well as very early in the spring. In summer they don't eat them. This is explained by the variability of the chemical composition of horsetails throughout the year. For example, the starch accumulated over the summer by the hibernating horsetail turns into sugars when low temperatures occur.

There is no information about the toxicity of horsetails to humans. On the contrary, young, slightly sweet, spore-bearing shoots of horsetail and starchy tubers of this species were previously widely used as food by the poor population of Eurasia and North America. Many horsetails were and are now used in folk medicine, and horsetail is included in the domestic state pharmacopoeia.

Until the 20th century field and forest horsetails were used to dye wool gray-yellow. The Indians of North America previously used horsetail rhizomes for weaving baskets. The hard stems of horsetail and similar species were widely used in Europe and North America instead of sandpaper for technical needs: for polishing furniture and horns, for cleaning metal parts during tinning and soldering, and simply for cleaning metal utensils.

Life of plants: in 6 volumes. - M.: Enlightenment. Edited by A. L. Takhtadzhyan, editor-in-chief, corresponding member. USSR Academy of Sciences, prof. A.A. Fedorov. 1974 .

Pharmacotherapeuticgroup. Diuretic, urolitic agent.

Description of the plant

text_fields

text_fields

arrow_upward

Rice. 8.18. Horsetail - Equisetum arvense L.

Horsetail grass- herba equiseti arvensis
- equisetum arvense l.
Sem. Horsetail- equisetaceae
Other names: pestles, pistils, field pine, earthen cones, marsh spruce, horsetail, horsetail, field spruce, marsh spruce.

perennial spore plant(sporophyte) with a long creeping rhizome and jointed stems.
Escapes two types. In early spring, spore-bearing shoots appear - juicy, thick, unbranched, 7-25 cm high, light brown or pinkish in color, bearing one apical strobile (spore-bearing spikelet) with spores. After sporulation they quickly die.
Controversy on spore-bearing shoots they ripen in April – May. In summer, from the same rhizome grow sterile vegetative thin shoots 10-50 cm high, green, with numerous leafless branches arranged in whorls.
Reduced leaves They are closed sheaths located at the nodes of the stem and branches (Fig. 8.18).
Whole plant hard and rough to the touch, since the walls of epidermal cells are impregnated with silicic acid.

Composition of horsetail

text_fields

text_fields

arrow_upward

Chemical composition The development of vegetative and spore-bearing shoots in species of the second group proceeds differently. For example, at

Main active ingredients horsetail herbs are

• flavonoids are derivatives of apigenin, luteolin, kaempferol and quercetin.

Also found

• phenolic acids,
• tannins,
• triterpene saponins,
• some alkaloids,
• a significant amount of silicic acid derivatives (about 10% of them in the form of water-soluble silicates).

Properties and uses of horsetail

text_fields

text_fields

arrow_upward

Pharmacological properties of horsetail

• improves urination,
• has hemostatic and anti-inflammatory properties,
• helps remove lead from the body.

Galenic forms of horsetail, as well as isolated glycoside luteolin, isolated from horsetail, has

• anti-inflammatory and
• antimicrobial action.

Silicon acid and its salts are found in most tissues of living organisms,

• influence the formation of bone tissue and collagen.

Application of horsetail

Horsetail preparations used as

• a diuretic for inflammatory diseases of the urinary tract (cystitis, urethritis, urolithiasis).

Horsetail herb is usually used in complex medical preparations.

As a diuretic horsetail is also used

• for heart diseases accompanied by congestion,
• with pulmonary heart failure,
• microhematuria and hemoptysis, especially of tuberculous etiology.

Horsetail preparations appoint

• for acute and chronic lead poisoning.

Horsetail is used in cosmetics

• Used for acne and for oily skin care.

Horsetail herb infusion use

• to strengthen hair.

Horsetail preparations are used strictly as prescribed by the doctor , as they may cause kidney irritation.

Horsetail preparations are contraindicated for nephritis and nephrosonephritis.

Spread of horsetail

text_fields

text_fields

arrow_upward

Spreading. It has an almost cosmopolitan type of habitat, found in the temperate zone of all continents. The entire territory of the country, except for deserts and semi-deserts; found even in the Arctic.

Habitat. Grows in meadows, river banks, among bushes. As a weed, it is found in fields and vegetable gardens, common along roadsides, on slopes of railway embankments, near ditches, in sandy and clay quarries. It often forms large thickets, convenient for harvesting. Horsetail is an indicator of acidic soils.

Procurement and storage of raw materials

text_fields

text_fields

arrow_upward

Preparation. Green vegetative shoots are harvested in the summer, cutting them with a sickle or knife at a height of 5-10 cm from the soil surface. You can collect raw materials throughout the summer in dry weather, since raw materials collected in wet weather turn black.

Before drying, yellowed branches are torn off, non-medicinal types of horsetails are separated, which are difficult to distinguish after drying.

Security measures. Since horsetail reproduces vegetatively, and the aerial part serves as the raw material, the same thickets can be used for several years in a row, then given a “rest” for 1-2 years to avoid depletion of the rhizomes.

Drying. The raw materials are dried outdoors in the shade or in dryers with artificial heating at a temperature of 40-50 ºС, spread out in a loose layer no more than 5 cm thick on paper or fabric. When drying in air, the raw materials are covered with a tarpaulin overnight.

Standardization. GF XI, issue. 2, art. 50, Changes No. 1,2.

Storage. The compressed grass is packed into bales or bales weighing 50 kg. Store in a dry, well-ventilated area. When humidity increases to 15-16%, the raw materials self-heat and acquire an unnatural odor. Shelf life up to 4 years.

External signs of raw materials, impurities, identification

text_fields

text_fields

arrow_upward

External signs of horsetail

Rice. 8.19. Horsetails:
A – horsetail; B – horsetail;
B – wintering horsetail; G – horsetail;
D – riverine horsetail; E – horsetail:
1 – spore-bearing shoot; 2 – leaf sheath; 3 – vegetative shoot.

Whole raw materials

Whole or partially crushed stems up to 30 cm long, hard, jointed, grooved, with 6-18 longitudinal ribs, whorled-branched almost from the base, with hollow internodes and thickenings at the nodes. The branches are unbranched, segmented, directed obliquely upward, 4-5-sided, without a cavity. The stem sheaths are cylindrical, 4-8 mm long, with triangular-lanceolate, dark brown, white-edged teeth, fused in groups of 2-3. The sheaths of the branches are green with 4-5 long brownish teeth. When branches are cut off, only the first short segments are retained on the stem. The color is grayish-green. The smell is weak. The taste is slightly sour. Crushed raw materials. Pieces of stems and branches, partly with nodes and sheaths, passing through a sieve with holes 7 mm in diameter. The color is grayish-green. The smell is weak. The taste is slightly sour. Powder. A mixture of particles passing through a sieve with holes 2 mm in diameter. The color is grayish-green with brown and whitish patches. The smell is weak. The taste is slightly sour.

Impurities

Shoots of other types of horsetails (Fig. 8.19), which are not used in medicine and grow in areas where horsetail is harvested, can be found as impurities. Distinctive characteristics of horsetail and other species that are impurities are given in the table.

Distinctive features of different types of horsetails
Plant name	Diagnostic signs
	Branch growth direction	Characteristics of branches	Characteristics of the teeth of the stem sheaths		Typical habitat
Horsetail - Equisetum arvense L.	Obliquely up	Usually unbranched, sometimes the lowest branches branch; 4-5-sided, without cavity	Triangular-lanceolate, sharp, black-brown, fused in 2-3		Fields, railway embankments, meadows, roadsides, banks of reservoirs
Swamp horsetail – Equisetum palustre L.	Obliquely up	Unbranched, rigid, 4-6-sided, with a cavity		Broadly lanceolate, unfused, brownish-black, with a wide white transparent border along the edge	Swamps, banks of reservoirs, marshy meadows and forests
Horsetail - Equisetum pratense Ehrh.	Horizontal or downward angled	Unbranched, soft, 3-sided		Subulate, unfused, small, along the edge with a narrow black border	Forb meadows, bushes, forests, forest clearings and edges
Horsetail - Equisetum sylvaticum L.	Horizontal or drooping	Strongly branched, soft, long, 4-sided		Large, thin (usually broken off in raw materials), light brown or brown, fused together in 2-5	Wet forests, meadows, swamp edges, forest clearings and edges
Riverside horsetail - Equisetum fluviatile L.	Obliquely up	Unbranched, soft, 6-sided, often completely absent		Lanceolate-subulate, black, unfused, pressed to the stem	Swamps, banks of reservoirs, mostly grows in water
Wintering horsetail – Equisetum hyemale L.	None	Stems unbranched, rarely branched, thick, hard, overwintering		Teeth are present only at the sheath in the upper node of the stem, brownish-black	Coniferous and mixed forests

Qualitative reactions

Determining the authenticity of raw materials involves chromatographic analysis on “Silufol” or “Sorbfil” plates of an alcoholic extract from the horsetail herb. In this case, in UV light, spots with blue fluorescence (flavone-5-glycosides) are detected on the chromatograms.

text_fields

text_fields

arrow_upward

Rice. 8.20. Microscopy of horsetail:
epidermis of the stem from the surface in the groove area:
1 – epidermal cell; 2 – stomata.

Looking at the stem and branches epidermal cells are visible from the surface, strongly elongated on the ribs with thickened straight or slightly curved porous walls, without stomata; in grooves and on reduced leaves - slightly elongated with more sinuous porous walls, with stomata.
Both types of the epidermis, on the walls of the ends (joints) of some cells, characteristic outgrowths are visible, from the surface they look like paired circles, when viewed in a longitudinal position - rounded or jagged with a clearly defined septum; some cells have papillary projections.
Stomata slightly submerged, with characteristic radiant folding of the cuticle, usually located in 3 rows, less often in 4, 2 or 1 (Fig. 8.20).
On a cross section of the stem under the epidermis areas of collenchyma are visible both in the ribs and in the grooves.
In the parenchyma of the cortex Large air cavities are located opposite the furrows.
Behind the faint endodermis opposite the ribs, conductive bundles are located in one row, also carrying one small cavity. The center of the internodes is hollow.
On a cross section of branches there are four large ribs, there is no central cavity.

Numerical indicators of raw materials

text_fields

text_fields

arrow_upward

Whole raw materials

Humidity no more than 13%; total ash no more than 24%; ash, insoluble in a 10% solution of hydrochloric acid, no more than 12%; other parts of the plant no more than 1%; other types of horsetails no more than 4%; organic impurity no more than 1%; mineral impurity no more than 0.5%.

Crushed raw materials

Humidity no more than 13%; total ash no more than 24%; ash, insoluble in a 10% solution of hydrochloric acid, no more than 12%; other parts of the plant no more than 1%; particles that do not pass through a sieve with holes with a diameter of 7 mm, no more than 10%; particles passing through a sieve with holes measuring 0.5 mm, no more than 15%; organic impurity no more than 1%; mineral impurity no more than 0.5%.

Powder

Humidity no more than 13%; total ash no more than 24%; ash, insoluble in a 10% solution of hydrochloric acid, no more than 12%; particles that do not pass through a sieve with holes with a diameter of 2 mm, no more than 15%; particles passing through a sieve with holes measuring 0.25 mm, no more than 5%.

Medicines based on horsetail

text_fields

text_fields

arrow_upward

1. Horsetail herb, crushed raw materials. Diuretic.
2. The composition includes the collection (antidiabetic collection “Arfazetin”; diuretic preparations “Bequorin” and “Herbafol”; collection for the preparation of medicine according to the prescription of M.N. Zdrenko).
3. The extract is part of complex preparations (“Fitolysin”, “Uroflux”, “Depuraflux”, “Marelin”, “Tonsilgon N”, etc.).