Subtropical plant of the nettle family. Pharmacognostic study of hemp nettle, stinging nettle and stinging nettle as a new type of medicinal plant material

Nettles include about 60 genera and more than 1000 plant species, distributed mainly in the tropics. The family is usually divided into 5 tribes: Urticeae proper, Procrideae, Boehmerieae, Forsskaoleae and Parietarieae.

The main difference between nettles in the order system is the orthotropic and banal or almost basal ovule, the straight spade-shaped embryo and the predominance of herbaceous life forms.

The evolution of the family proceeded mainly along the line of simplifying the structure of organs and reducing their parts. The features of reduction in nettles are especially clearly manifested in the flower: the gynoecium has completely lost its dimeric structure, and the number of flower parts can be reduced to the limit. In the tribe Forscaoleidae, for example, male flower usually consists of one stamen surrounded by a perianth; the female contains only a gynoecium, its perianth is completely reduced, and an undivided perianth rarely develops. The inflorescences of nettles of the topaceous type are varied in shape: capitate, paniculate, catkin-shaped. Sometimes they are bisexual and contain one or several female and several male flowers, but more often the inflorescences are unisexual.

Nettles are wind-pollinated plants. Their stamens in the buds are usually bent inward, but by the time they pollen, the filaments instantly straighten, the anthers crack from the shock and throw out pollen. This device for dispersing pollen is a characteristic feature of nettles.

The fruits of nettles are small, dry (nut-like), but in some species they are surrounded by a succulent cover of a fleshy calyx that grows after flowering, making the fruit look like a drupe or berry. In Urera baccifera, a small tree common in the tropical forests of America, the overgrown calyx is brightly colored, which makes the fruit even more similar to a berry. Similar to the berries are the reddish-orange fruits of the Procris species, the fleshy part of these fruits is formed by the receptacle. The reddish-purple fruits of Laportea moroides are very similar to the fruits of mulberries or raspberries, however, unlike them, the fleshy part of the fruit in this plant arose mainly due to the growth of the peduncle.

Nettles bear fruit abundantly, and in some species the seeds can develop asexually as a result of apomixis. For example, a number of species of elatostema (Elatostema acuminatum, E. sessile) have almost no male flowers, however, female flowers produce fruits with full seeds. Observations on the formation of seeds have shown that in these plants the micropyle is overgrown long before the embryo sac matures and the embryo arises from an unreduced egg without pollination and without fertilization.

Most nettles have the most in the usual way The distribution of fruits is zoochory, however, in a number of species of Elatostema and Pilea, the fruits are catapulted in a peculiar way, and the role of the catapult is played by staminodes. During the period of flower dusting, staminodes are barely noticeable, and only at the time of fruiting do they significantly increase in size. At this time, the staminodes are bent inward and support the fruit partially hanging over them (Fig. 148). As soon as a separating layer forms on the stalk and the connection between the fruit and the plant weakens, the staminodes straighten with force and eject (catapult) the fruit. In this case, the fruits fly away at a distance of 25-100 m from mother plant. However, in most nettles the most common route of fruit dispersal remains zoochory.

Nettles very often reproduce vegetatively by rooting stems, underground stolons, root suckers, tubers, etc. In herbaceous succulents, this method of reproduction often prevails over the seed method.

Nettle leaves are simple, usually with 3 veins at the base, one of characteristic features they are an abundance of cystoliths - whitish formations impregnated with calcium carbonate (Fig. 148). The shape of cystoliths (pointed, rod-shaped, oval, crescent-shaped, club-shaped, stellate, F-shaped, etc.) is more or less constant for certain taxa and often serves as a good diagnostic feature in the taxonomy of species and genera of the family.

The leaves of primitive forms of nettles are arranged oppositely on the shoots; in more advanced forms, the leaf arrangement may change to double-rowed-alternate, due to the reduction of one leaf in each pair of opposite leaves. There are many intermediate stages along the path of this transition. Most often, one of the opposite leaves does not disappear completely, but only decreases in size, and then we are faced with a very characteristic phenomenon for nettles - anisophylly - the development in one node of leaves that are unequal in size and sometimes in shape (Fig. 148).

The most well known in the family are representatives of the nettle tribe, which unites burning plants. The Latin name of the tribe Urticeae (as well as Urtica, Urlicaceae and Urlicales), derived from the word uro - burning, was given to it for the many burning hairs covering the leaves and stems of plants. Stinging nettle hairs have stinging cells (per 1 mg of its mass there are up to 100 stinging cells) containing a caustic liquid of a complex chemical composition; it contains histamine, acetylcholine, formic acid. The burning hair looks like a capillary tube ending in a small round head (Fig. 147). Top part The hair becomes silicified and breaks off when touched, the sharp edges of the hair pierce the skin, and the contents of the stinging cell are injected into the wound. The result is a painful burning sensation - a nettle burn.

Burns caused by tropical representatives of the tribe, especially arboreal laportheas, sometimes lead to serious consequences. The stinging effect of Laportea urentissima, which grows in South-East Asia, so strong that it can cause the death of a child. The arboreal Laporteas of the Philippines are also notorious: Luzon Laportea (L. luzonensis) and semi-closed Laportea (L. subclausa). The stinging hairs of the Australian giant laporthea (L. gigas), a large tree from the tropical rainforests of North-Eastern Australia, are incredibly painful; the pain from her burn often leads to fainting and is felt for several months. The same burns, accompanied by tumors of the lymph nodes, are caused by the Australian succulent Laportea mulberry, growing in our greenhouses as an herbaceous plant, and the shrubby Laportea light-leaved (L. photiniphylla) from the Fiji Islands, New Caledonia and Australia. The burns of the sultry laporthea (L. aestuans), a small creeping herbaceous plant of the Antilles, are unpleasant. The touch of the herbaceous girardinia heterophylla (Girarclinia heterophylla), common in Indochina, is very painful.

Stinging hairs protect the plant from being eaten by animals, but, of course, they do not save it from all enemies. The leaves of the Australian tree Laportea, for example, turned out to be harmless to large cattle, nettle leaves are eaten by snails with impunity, etc. It is therefore not surprising to see additional protective devices in plants. Upepa berry-bearing, for example, in addition to stinging hairs, develops many spines on the shoots, in addition, it is one of the few nettles that have milky juice. Laporte and nettles also have laticifers, but they contain a colorless liquid and not milky juice, like most mulberries.

In terms of the number of species in the tribe, the dominant genus is the nettle (Urtica), containing approximately 50 species of herbaceous plants, and the tropical genus Urera (35 species), represented by different life forms: herbaceous plants, shrubs, softwood trees and vines, the latter including most African species. In the USSR, only species of nettles from the Urticeae tribe are widespread (Fig. 147). Everyone knows nettle as a stinging weed, but not everyone knows that common nettle (U. dioica) - most useful plant our temperate flora (Fig. 147). It is rich in vitamins A, C, K and mineral salts, its leaves and young shoots are edible, they are used raw (mashed) and boiled. IN folk medicine it is successfully used as a hemostatic agent for internal bleeding, as well as for vitamin deficiency. Nettle seeds are rich in oil, the leaves are successfully used to feed silkworms, yellow dye is obtained from the roots, and green dye is obtained from the leaves. Nettle has long been known as a spinning plant; in past times it was a common raw material for making handicraft fabrics. The bactericidal effect of nettle is well known to fishermen, and they use it to preserve fresh fish (the insides of the fish are removed and stuffed with nettles).

An invariable companion of human habitation - stinging nettle - is distributed cosmopolitanly; stinging nettle (U. urens) also has a cosmopolitan habitat - smaller and more stinging annual plant(Fig. 147). These plants also differ in the nature of the distribution of flowers: in stinging nettle both male and female flowers are located on the same plant, in dioecious nettle - usually on different plants. Hemp nettle (U. cannabina, Fig. 147) sharply differs from them with 3-5 divided leaves, similar to hemp leaves. Its range extends across the Asian part of the USSR, Mongolia, Japan and China. Another unique type of nettle is ball-shaped nettle (U. pilulifera) - a small bluish plant with whole leaves and spherical inflorescences on long stalks located in their axils. Its habitat covers the Mediterranean, in our country it grows in the Crimea and the Caucasus, occasionally found in the south of the European part of the USSR.

In addition to nettles, in the USSR Girardinia cuspidata and Laportea bulbifera are occasionally found from this tribe; fleshy tubers develop in the axils of the leaves of the latter, with the help of which it reproduces vegetatively. Both types are common in Far East. It's high herbaceous plants with stinging hairs, like nettles.

The largest tribe of procrisids includes more than 700 species of mostly herbaceous, often succulent plants, living mainly under the canopy of tropical rainforests or in humid habitats in semi-deciduous tropical forests - near streams, under rocks, in gorges. The tribe is dominated by the pantropical genus Pilea (about 400 species), uniting herbaceous plants with intra-axillary fused stipules, predominantly a 3-loiast perianth in female flowers (Fig. 148) and clearly defined cystoliths of various shapes on the leaves and stems.

The genus Elatostema is widespread in the tropics of the Old World, including (together with Pellionia) about 300 species of herbaceous plants. Very close to it is the small (16-20 species) paleotropical genus Procris; its representatives, predominantly herbaceous or shrubby epiphytes with succulent leaves and stems, grow on the trunks and lower branches of trees. Procris are common on the islands of Indonesia and the Philippines, but in general the range of the genus extends from tropical Africa, through the tropics of Southeast Asia, the islands of Micronesia and the Solomon Islands to Polynesia.

In the USSR (in the Far East), 3 types of pili with crosswise opposite leaves grow from procrisaceae. These are a small (up to 7 cm high) Pilea rotundifolia, Japanese Pilea (P. japonica), also common in Japan and China, and the perennial herbaceous Mongolian Pilea (P. mongolica), growing in Transbaikalia.

Pili species and other representatives of this tribe are better known to us as graceful, widely cultivated ornamental plants. Particularly attractive are the variegated forms, climbing plants with reddish leaves - small herbaceous succulents, similar in habit to a tree (Table 39). This is small-leaved Pilea (P. microphylla) - an American plant, widely used as an ornamental plant in the Old World. In Southeast Asia, in addition, the sour shoots of this pili are eaten.

Pilea smallifolia blooms profusely, its millimeter-long pinkish flowers (Table 39) open at different times, and the anthers also crack one by one, suddenly throwing clouds of yellowish pollen into the air. It seems to shoot out pollen, which is why this graceful little pilea is called the “artillery plant.”

The Bemeriidae tribe has a pantropical distribution (only individual species extend into regions of warm-temperate climate) and unites approximately 16 genera and about 250 species for the most part herbaceous plants with characteristic large and usually coarsely toothed leaves arranged crosswise in opposite directions. In the axils of the leaves there are capitate or catkin-shaped inflorescences. In some tropical Bemeria, the thread-like axes of female inflorescences sometimes reach 50-100 cm in length and look like beards of lichens; more often, the flowers are collected on the inflorescence axis into separate spherical heads, making the overall inflorescence look like a string of beads.

Among the Boehmeriaceae there are many spinning plants, and the most valuable of them is considered to be ramie (Boehmeria nivea) - a large herbaceous plant with whole, white-silver leaves below. Silky fiber is obtained from its bast, which is used to make a variety of woven fabrics. The fibers of ramie are several times longer than those of other spinning plants, they reach 500 mm. Ramie comes from China, but has long been cultivated in many countries, including the USSR (mainly in Central Asia and Transcaucasia), and has not yet lost its importance in the textile industry. Fibers from the green bemeria (B. viridis) and representatives of some other genera of the tribe (Pipturus, Maoutia, Pouzolzia, Leucosyke) are also used for yarn.

The small tribe Forscaoleaceae, consisting of 3 genera, has long attracted the attention of researchers with its extremely reduced flowers, which are not at all similar in appearance to nettle flowers. Their small, few-flowered inflorescences are also unique: they are enclosed in a wrapper that imitates a perianth and look like individual flowers.

This tribe is one of the most specialized in the family and at the same time, undoubtedly, very ancient, as evidenced by the areas of its genera. The genus Australina (Fig. 149), for example, is distributed in South Africa, in the mountains of Northeast Africa, South Australia, Tasmania and New Zealand. Huge gaps in the range of australina indicate its antiquity and suggest that in the distant past the distribution of the genus was associated with southern continent Gondwana, which broke up more than 75 million years ago and gave rise to South America, Africa, India, Australia and Antarctica. The genus Drougetia appears to have similar connections; its members now grow naturally in Southern and Eastern Africa, Madagascar and India.

Completely different ancient connections are shown by the distribution of the genus Forsskaolea. Its modern range extends from the Canary Islands through North Africa, Southern Europe, Western Asia and Afghanistan to India and thus covers a number of areas of the Ancient Mediterranean floristic sub-kingdom of Holarctis. It is likely that this genus spread in the Cretaceous period as part of the Cretaceous subtropical flora along the shores and islands of the ancient Tethys Sea.

A small tribe of postenaceae (5 genera and about 30 species), the most advanced in the nettle family, includes herbaceous and shrubby plants with entire, mostly alternate leaves, their inflorescences are single- to multi-flowered, often with involucres, the perianth of the female flowers is tubular.

The tribe is dominated by the genus Parietaria, which differs somewhat from other nettles in its distribution mainly in the warm-temperate zone and the clear predominance of bisexual flowers. Wallworts, usually tender herbaceous plants, sometimes woody in the lower part, grow in damp places in shaded areas, among rocks and stones; often appear on screes, along mountain slopes reaching an altitude of 3000 m above sea level (Central Asia). Their range covers mainly the temperate regions of Eurasia, but the weak wallflower (P. debilis) is much more widespread and is found on all five continents. Its range is often cited as an example of the extraordinary breadth of the species’ natural distribution. However, it is possible that wallflower was introduced into a number of countries as a result of human activity.

Among the wallflowers there are many pioneer plants, and weeds are not uncommon. Their seeds are usually distributed by animals. The seeds of the Lusitanian wallflower (P. lusitanica) are carried by ants; they harvest the fruits of this plant for the sake of elaiosomes - oily appendages into which the bases of its perianths turn.

In the USSR, 5 types of wallflower are common; they grow in the south of the European part, the Caucasus, Central Asia and the Far East (stoneweed - P. officinalis, wallflower Lusitanian, wallflower of Judaea - P. judaica, wallflower - P. alsinifolia and wallflower small-flowered - P. micrantha, which some researchers identify with weak wallflower).

The family has about 45 genera and over 850 species, widely distributed throughout the globe, but mainly in the tropics and mountain moist subtropical forests, with a few species in temperate countries.

Life form: herbs, less often - shrubs or small trees. Leaves are simple, with opposite or alternate leaf arrangement; often (but not always) with stipules. Cystoliths and long bast fibers are characteristic. The flowers are usually dioecious, small, with a simple, inconspicuous perianth of 4-5 free or fused leaflets. There are as many stamens as there are tepals opposing them. Gynoecium of 2 fused carpels. The ovary is superior, unilocular, with one ovule. The column is also one, ending different number stigma. Flowers in cymose inflorescences (catkin-shaped, paniculate, capitate), based on thyrsus. The fruits are pseudomonocarpous - a nut, often very small, or an achene. Seeds with

\endosperm. In many, the fruits are distributed by animals (zoochory). But also vegetative propagation is no less important.

From the family Nettle (Urtica), all 30-35 species of which have stinging emergents, the most famous being monoecious stinging nettle (U. urens) And stinging nettle (U. dioica)(Fig. 8.6). Stinging nettle - high perennial, quickly spreading through rhizomes, living as a weed near human habitation. Stinging nettle is a typical nitrophile, as it lives in soils with a high nitrogen content. Her burning emergent has a flask-shaped base and a hook at the top, under which cell walls silicified and become extremely brittle. Upon contact with the top of the emergent, it breaks off, sharp fragments penetrate the skin, and cell sap is injected into the wound. Histamine orecholine, various organic acids (including formic acid) and their salts were found in the cell sap. Other types of nettle are no less stinging, including nettle (U.cannabina) with leaves resembling hemp. Painful sensations during burns of some tropical species of the genus Laportea last for several months. But not all nettles have stinging hairs; for example, the genus Pilea. Species of this genus are often cultivated as indoor ornamental plants.

Rice. 8.6. Nettles. Stinging nettle (Urtica dioica):

1 - part of a male plant;

2 - male flower; 3 - longitudinal section of a female flower; 4 - diagram of a male flower A 5 - diagram of a female flower (9)

Stinging nettle - famous medicinal plant, rich in vitamins, mainly A, C and flavonoids. Its young leaves are used to prepare salads and soups, and in dried form they are used in medicine as a hemostatic agent.

Order Euphorbiaceae(Euphorbiales)

The order includes 4 families, the most important of which is the family of Euphorbiaceae proper.

NETTLE FAMILY - URTICACEAE

Nettles include about 60 genera and more than 1000 species plants distributed mainly in the tropics.

The main difference between nettles in the order system is the orthotropic and basal or almost basal ovule, straight spatulate embryo and predominance herbaceous life forms , less often bushes , trees with soft wood and vine, the latter include most African species.

Leaves nettles are simple, usually with 3 veins at the base; one of their characteristic features is the abundance of cystoliths - whitish formations impregnated with calcium carbonate. The shape of cystoliths (pointed, rod-shaped, oval, crescent-shaped, club-shaped, stellate, F-shaped, etc.) is more or less constant for certain taxa and often serves as a good diagnostic feature in the taxonomy of species and genera of the family.
The leaves of primitive forms of nettles are arranged oppositely on the shoots; in more advanced forms, the leaf arrangement may become double-rowed, due to the reduction of one leaf in each pair of opposite leaves. There are many intermediate stages along the path of this transition. Most often, one of the opposite leaves does not disappear completely, but only decreases in size, and then we are faced with a very characteristic phenomenon for nettles - anisophidly - the development in one node of leaves that are unequal in size and sometimes in shape.

Inflorescences nettles of the topaceous type, varied in shape: capitate, paniculate, catkin-shaped. Sometimes they are bisexual and contain one or several female and several male flowers, but more often the inflorescences are unisexual.

The evolution of the family proceeded mainly along the line of simplifying the structure of organs and reducing their parts. The features of reduction in nettles are especially clearly manifested in flower: the gynoecium has completely lost its dimeric structure, and the number of flower parts can be reduced to the limit. In the tribe Forscaoleaceae, for example, the male flower usually consists of one stamen surrounded by a perianth, the female flower contains only a gynoecium, its perianth is completely reduced, and an undivided perianth rarely develops.

Nettles - wind-pollinated plants. Their stamens in the buds are usually bent inward, but by the time they pollen, the filaments instantly straighten, the anthers crack from the shock and throw out pollen. This device for dispersing pollen is a characteristic feature of nettles.

Fruit nettles are small, dry (nut-shaped), but in some species they are surrounded by a succulent cover of a fleshy calyx that grows after flowering, making the fruit look like a drupe or berry.
Nettles bear fruit abundantly, and in some species the seeds can develop asexually as a result of apomixis. For example, in a number of Elatostema species ( Elatostema acuminatum, E. sessile) there are almost no male flowers, however, female flowers produce fruits with full seeds. Observations on the formation of seeds have shown that in these plants the micropyle is overgrown long before the embryo sac matures and the embryo arises from an unreduced egg without pollination and without fertilization.

In most nettles, the most common distribution method fruits are zoochory, however, in a number of species, elathostema and pilea ( Pilea) the fruits are catapulted in a peculiar way, and the role of the catapult is played by the staminodes. During the period of flower dusting, staminodes are barely noticeable, and only at the time of fruiting do they significantly increase in size. At this time, the staminodes are bent inward and support the fruit partially hanging over them. As soon as a separating layer forms on the stalk and the connection between the fruit and the plant weakens, the staminodes straighten with force and eject (catapult) the fruit. In this case, the fruits fly away at a distance of 25-100 m from the mother plant. However, in most nettles the most common route of fruit dispersal remains zoochory.

Nettles are very common multiply vegetatively by rooting stems, underground stolons, root shoots, tubers, etc. In herbaceous succulents, this method of reproduction often prevails over the seed method.

The family is usually divided into 5 tribes: nettles proper ( Urticeae), procrisaceae ( Procrideae), bemeriaceae ( Boehmerieae), forscaoleaceae ( Forsskaoleae) and post-stellate ( Parietarieae).

Best known in the family representatives nettle tribes , uniting burning plants. Latin name of the tribe Urticeae(as well as Urtica, Urticaceae And Urticales), a derivative of the word uro - burning, given to it for the many burning hairs covering the leaves and stems of plants. Stinging nettle hairs have stinging cells (there are up to 100 stinging cells per 1 mg of its mass), containing a caustic liquid of a complex chemical composition; it contains histamine, acetylcholine, formic acid. The burning hair looks like a capillary tube ending in a small round head. The upper part of the hair becomes silicified and breaks off when touched, the sharp edges of the hair pierce the skin, and the contents of the stinging cell are injected into the wound. The result is a painful burning sensation - a nettle burn.
Stinging hairs protect the plant from being eaten by animals, but, of course, they do not save it from all enemies. The leaves of the Australian tree laportea, for example, turned out to be harmless to cattle, the leaves of nettles are eaten with impunity by snails, etc. It is therefore not surprising to see additional protective devices in plants. Urera berry-bearing, for example, in addition to stinging hairs, develops many spines on its shoots; in addition, it is one of the few nettles that has milky juice. Laporte and nettles also have laticifers, but they contain a colorless liquid and not milky juice, like most mulberries.

In terms of the number of species in the tribe, the genus predominates nettle (Urtica), containing approximately 50 species of herbaceous plants, and the tropical genus urra(35 species), represented by different life forms: herbaceous plants, shrubs, trees with soft wood and vines, the latter including most African species. In Russia from the tribe Urticeae Only the nettle species are widespread.

Everyone knows nettle as a stinging weed, but not everyone knows that the common stinging nettle (U. dioica) - most useful plant of our temperate flora. It is rich in vitamins A, C, K and mineral salts, its leaves and young shoots are edible, they are used raw (mashed) and boiled. In folk medicine, it is successfully used as a hemostatic agent for internal bleeding, as well as for vitamin deficiency. Nettle seeds are rich in oil, the leaves are successfully used to feed silkworms, yellow dye is obtained from the roots, and green dye is obtained from the leaves. Nettle has long been known as a spinning plant; in past times it was a common raw material for making handicraft fabrics. The bactericidal effect of nettle is well known to fishermen, and they use it to preserve fresh fish (the insides of the fish are removed and stuffed with nettles).
An invariable companion of human habitation - stinging nettle - is distributed cosmopolitanly; stinging nettle also has a cosmopolitan habitat ( U. urens) is a smaller and more pungent annual plant. These plants also differ in the nature of the distribution of flowers: in stinging nettle both male and female flowers are located on the same plant, in dioecious nettle - usually on different plants. Sharply different from them with 3-5 divided leaves, similar to hemp leaves, hemp nettle ( U. cannabina). Its range extends across the Asian part of Russia, Mongolia, Japan and China. Another unique type of nettle is the ball nettle ( U. pilulifera) is a small bluish plant with whole leaves and spherical inflorescences on long stalks located in their axils. Its habitat covers the Mediterranean, in our country it grows in the Crimea and the Caucasus, occasionally found in the south of the European part of Russia.
In addition to nettles, in Russia from this tribe Girardinia acuminata is occasionally found ( Girardinia cuspidata) and Laportea bulbosa ( Laportea bulbifera), in the axils of the leaves of the latter fleshy tubers develop, with the help of which it reproduces vegetatively. Both species are common in the Far East. These are tall herbaceous plants with stinging hairs, like nettles.

Get acquainted with morphological structure flower and inflorescence can be found on the page "Handbook of morphology of herbaceous plants".

And on the website of the Ecosystem Ecological Center you can see the distribution of herbaceous plant species by ecological groups and habitats (biotopes) middle zone Russia:

Nettle family (Urticaceae) (I. A. Grudzinskaya)

The main difference between nettles in the order system is the orthotropic and basal or almost basal ovule, the straight spade-shaped embryo and the predominance of herbaceous life forms.

The evolution of the family proceeded mainly along the line of simplifying the structure of organs and reducing their parts. The features of reduction in nettles are especially clearly manifested in the flower: the gynoecium has completely lost its dimeric structure, and the number of flower parts can be reduced to the limit. In the tribe Forscaoleaceae, for example, the male flower usually consists of one stamen surrounded by a perianth, the female contains only gynoecium, its perianth is completely reduced, and an undivided perianth rarely develops. The inflorescences of nettles are of the topaceous type, varied in shape: capitate, paniculate, catkin-shaped. Sometimes they are bisexual and contain one or several female and several male flowers, but more often the inflorescences are unisexual.

Nettles bear fruit abundantly, and in some species the seeds can develop asexually as a result of apomixis. For example, a number of species of elatostema (Elatostema acuminatum, E. sessile) have almost no male flowers, however, female flowers produce fruits with full-fledged seeds. Observations on the formation of seeds have shown that in these plants the micropyle is overgrown long before the embryo sac matures and the embryo arises from an unreduced egg without pollination and without fertilization.

In most nettles, the most common method of distributing fruits is zoochory, however, in a number of species of Elatostema and Pilea, the fruits are catapulted in a peculiar way, and the role of the catapult is played by staminodes. During the period of flower dusting, staminodes are barely noticeable, and only at the time of fruiting do they significantly increase in size. At this time, the staminodes are bent inward and support the fruit partially hanging over them (Fig. 148). As soon as a separating layer forms on the stalk and the connection between the fruit and the plant weakens, the staminodes straighten with force and eject (catapult) the fruit. In this case, the fruits fly away at a distance of 25 - 100 m from the mother plant. However, in most nettles the most common route of fruit dispersal remains zoochory.

Nettles very often reproduce vegetatively by rooting stems, underground stolons, root suckers, tubers, etc. In herbaceous succulents, this method of reproduction often prevails over the seed method.

The leaves of nettles are simple, usually with 3 veins at the base; one of their characteristic features is the abundance of cystoliths - whitish formations impregnated with calcium carbonate (Fig. 148). The shape of cystoliths (pointed, rod-shaped, oval, crescent-shaped, club-shaped, stellate, V-shaped, etc.) is more or less constant for certain taxa and often serves as a good diagnostic feature in the taxonomy of species and genera of the family.

The most well known in the family are representatives of the nettle tribe, which unites burning plants. The Latin name of the tribe Urticeae (as well as Urtica, Urticaceae and Urticales), derived from the word uro - burning, was given to it for the many burning hairs covering the leaves and stems of plants. Stinging nettle hairs have stinging cells (there are up to 100 stinging cells per 1 mg of its mass), containing a caustic liquid of a complex chemical composition; it contains histamine, acetyl choline, formic acid. The burning hair looks like a capillary tube ending in a small round head (Fig. 147). The upper part of the hair becomes silicified and breaks off when touched, the sharp edges of the hair pierce the skin, and the contents of the stinging cell are injected into the wound. The result is a painful burning sensation - a nettle burn.

Burns caused by tropical representatives of the tribe, especially arboreal laportheas, sometimes lead to serious consequences. The stinging effect of Laportea urentissima, native to Southeast Asia, is so strong that it can cause the death of a child. The arboreal Laporteas of the Philippines are also notorious: the Lusopian Laportea (L. Luzonensis) and the semi-closed Laportea (L. subclausa). The stinging hairs of the Australian giant laporthea (L. gigas), a large tree from the tropical rainforests of North-Eastern Australia, are incredibly painful; the pain from her burn often leads to fainting and is felt for several months. The same burns, accompanied by tumors of the lymph nodes, are caused by the Australian succulent Laportea mulberry, growing in our greenhouses as an herbaceous plant, and the shrubby Laportea light-leaved (L. photiniphylla) from the Fiji Islands, New Caledonia and Australia. The burns of Laporteizina (L. aestuans), a small creeping herbaceous plant of the Antilles, are unpleasant. The touch of the herbaceous Girardinia heterophylla, common in Indochina, is very painful.

Stinging hairs protect the plant from being eaten by animals, but, of course, they do not save it from all enemies. The leaves of the Australian tree laportea, for example, turned out to be harmless to cattle, the leaves of nettles are eaten with impunity by snails, etc. It is therefore not surprising to see additional protective devices in plants. Urera berry-bearing, for example, in addition to stinging hairs, develops many spines on its shoots; in addition, it is one of the few nettles that has milky juice. Laporte and nettles also have laticifers, but they contain a colorless liquid and not milky juice, like most mulberries.

In terms of the number of species in the tribe, the genus predominates nettle(Urtica), containing approximately 50 species of herbaceous plants, and the tropical genus Urera (35 species), represented by various life forms: herbaceous plants, shrubs, softwood trees and lianas, the latter including most African species. In the USSR, only species of nettles from the Urticeae tribe are widespread (Fig. 147). Everyone knows nettle as a stinging weed, but not everyone knows that common nettle (U. dioica) is the most useful plant of our temperate flora (Fig. 147). It is rich in vitamins A, C, K and mineral salts, its leaves and young shoots are edible, they are used raw (mashed) and boiled. In folk medicine, it is successfully used as a hemostatic agent for internal bleeding, as well as for vitamin deficiency. Nettle seeds are rich in oil, the leaves are successfully used to feed silkworms, yellow dye is obtained from the roots, and green dye is obtained from the leaves. Nettle has long been known as a spinning plant; in past times it was a common raw material for making handicraft fabrics. The bactericidal effect of nettle is well known to fishermen, and they use it to preserve fresh fish (the insides of the fish are removed and stuffed with nettles).

An invariable companion of human habitation - stinging nettle - is distributed cosmopolitanly; stinging nettle (U. urens) - a smaller and more stinging annual plant - also has a cosmopolitan habitat (Fig. 147). These plants also differ in the nature of the distribution of flowers: in stinging nettle both male and female flowers are located on the same plant, in dioecious nettle - usually on different plants. The hemp nettle (U. cannabina, Fig. 147) differs sharply from them with 3-5 divided leaves, similar to hemp leaves. Its range extends across the Asian part of the USSR, Mongolia, Japan and China. Another unique type of nettle is ball-shaped nettle (U. pilulifera) - a small bluish plant with whole leaves and spherical inflorescences on long stalks located in their axils. Its habitat covers the Mediterranean, in our country it grows in the Crimea and the Caucasus, occasionally found in the south of the European part of the USSR.

In addition to nettles, in the USSR Girardinia cuspidata and Laportea bulbifera are occasionally found from this tribe; fleshy tubers develop in the axils of the leaves of the latter, with the help of which it reproduces vegetatively. Both species are common in the Far East. These are tall herbaceous plants with stinging hairs, like nettles.

The largest tribe of procrisids includes more than 700 species of mostly herbaceous, often succulent plants, living mainly under the canopy of tropical rainforests or in humid habitats in semi-deciduous tropical forests - near streams, under rocks, in gorges. The tribe is dominated by the pantropical genus Pilea (about 400 species), uniting herbaceous plants with intra-axillary fused stipules, predominantly a 3-lobed perianth in female flowers (Fig. 148) and clearly defined cystoliths of various shapes on the leaves and stems.

The genus Elatostema is widespread in the tropics of the Old World, including (together with Pellionia) about 300 species of herbaceous plants. Very close to it is the small (16 - 20 species) paleotropical genus Procris; its representatives, mainly herbaceous or shrubby epiphytes with succulent leaves and stems, grow on the trunks and lower branches of trees. Procris are common on the islands of Indonesia and the Philippines, but in general the range of the genus extends from tropical Africa, through the tropics of Southeast Asia, the islands of Micronesia and the Solomon Islands to Polynesia.

In the USSR (in the Far East), 3 types of pili with crosswise opposite leaves grow from procrisaceae. These are the small (up to 7 cm high) Pilea rotundifolia, Japanese Pilea (P. japonica), also common in Japan and China, and the perennial herbaceous Mongolian Pilea (Pe mongolica), growing in Transbaikalia.

Pili species and other members of this tribe are better known to us as graceful, widely cultivated ornamental plants. Particularly attractive are the variegated forms, climbing plants with reddish leaves - small herbaceous succulents, similar in habit to the tree bl. 39). This is small-leaved Pilea (P. microphylla) - an American plant, widely used as an ornamental plant in the Old World. In Southeast Asia, in addition, the sour shoots of this pili are eaten.

The tribe Bemeriaceae has a pantropical distribution (only a few species enter regions of warm-temperate climates) and unites approximately 16 genera and about 250 species of mostly herbaceous plants with characteristic large and usually coarsely toothed leaves arranged crosswise opposite. In the axils of the leaves there are capitate or catkin-shaped inflorescences. In some tropical Bemerias, the thread-like axes of female inflorescences sometimes reach 50-100 cm in length and look like the beards of lichens; more often, the flowers are collected on the inflorescence axis into separate spherical heads, making the overall inflorescence look like a string of beads.

Among the Boehmeriaceae there are many spinning plants, and the most valuable of them is considered to be ramie (Boehmeria nivea) - a large herbaceous plant with whole, white-silver leaves below. Silky fiber is obtained from its bast, which is used to make a variety of fabrics. The fibers of ramie are several times longer than those of other spinning plants, they reach 500 mm. Ramie comes from China, but has long been cultivated in many countries, including the USSR (mainly in Central Asia and Transcaucasia), and has not yet lost its importance in the textile industry. Fibers from green bemeria (B. viridis) and representatives of some other genera of the tribe (Pipturus, Maoutia, Pouzolzia, Leucosyke) are also used for yarn.

The small tribe Forscaoleaceae, consisting of 3 genera, has long attracted the attention of researchers with its extremely colorful flowers, which are not at all similar in appearance to nettle flowers. Their small, few-flowered inflorescences are also unique: they are enclosed in a wrapper that imitates a perianth and look like individual flowers.

This tribe is one of the most specialized in the family and at the same time, undoubtedly, very ancient, as evidenced by the areas of its genera. The genus Australina (Fig. 149), for example, is distributed in South Africa, in the mountains of Northeast Africa, South Australia, Tasmania and New Zealand. Huge gaps in the range of Australina indicate its antiquity and suggest that in the distant past the distribution of the genus was associated with the southern continent of Gondwana, which broke up more than 75 million years ago and gave rise to South America, Africa, India, Australia and Antarctica. The genus Drougetia appears to have similar connections; its members now grow naturally in Southern and Eastern Africa, Madagascar and India.

A small tribe of postenaceae (5 genera and about 30 species), the most advanced in the nettle family, includes herbaceous and shrubby plants with entire, mostly alternate leaves, their inflorescences are single multi-flowered, often with involucres, the perianth of the female flowers is tubular.

The tribe is dominated by the genus Parietaria, which differs somewhat from other nettles in its distribution mainly in the warm-temperate zone and the clear predominance of bisexual flowers. Wallworts, usually tender herbaceous plants, sometimes woody in the lower part, grow in damp places in shaded areas, among rocks and stones; often appear on screes, along mountain slopes reaching an altitude of 3000 m above sea level (Central Asia). Their range covers mainly the temperate regions of Eurasia, but the weak wallflower (P. debilis) is distributed much more widely and is found on all five continents. Its range is often cited as an example of the extraordinary breadth of the species’ natural distribution. However, it is possible that wallflower was introduced into a number of countries as a result of human activity.

Among the wallflowers there are many pioneer plants, and weeds are not uncommon. Their seeds are usually distributed by animals. The seeds of the Lusitanica plant (P. lusitanica) are carried by ants; they harvest the fruits of this plant for the sake of elaiosomes - oily appendages into which the bases of its perianths turn.

In the Ancient Mediterranean floristic subkingdom, the remaining 4 genera of the tribe are also widespread, and Gesnouinia arborea, growing on the Canary and Azores Islands, corresponds to tropical America (in the Antilles and in the northern regions South America) also tree-like forms of representatives of the genus Hemistylis, while the herbaceous Rousselia humilis, growing on the Antilles, is replaced in the Mediterranean of the Old World by the herbaceous soleirolia (Soleirolia soleirolii).

Soleirolia is a small climbing plant with densely seated small rounded leaves and single flowers, the involucres of which are covered with curved clinging hairs (Fig. 149). It is common in Southern Europe and is readily cultivated in our greenhouses and gardens, mainly due to the ability to quickly spread vegetatively and cover the free territory with a green decorative carpet.

Subtropical plant of the nettle family. Pharmacognostic study of hemp nettle, stinging nettle and stinging nettle as a new type of medicinal plant material

Nettle family (Urticaceae) (I. A. Grudzinskaya)

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