1. Characteristics of the nettle family

nettle medicinal plant

Nettle family - URTICACEAE

Systematic position

In traditional taxonomy, the family has its own order - nettles (Urticales):

Department of flowering (angiospermous) plants (Magnoliophyta, Angiospermophyta)

Dicot class (Magnoliopsida, Dicotyledones)

Subclass Hamamelid (Hamamelididae)

Order Nettles (Urticales)

Elm family (Ulmaceae)

Mulberry family (Moraceae)

Cannabis family (Cannabaceae)

Cecropia family (Cecropiaceae)

Nettle family (Urticaceae)

Nettles include about 60 genera and more than 1000 plant species, distributed mainly in the tropics. They grow mainly in the temperate zone in the Northern and (less often) Southern hemispheres.

The main difference of nettles in the order system is the orthotropic and basal or almost basal ovule, straight shovel-shaped embryo and the predominance of herbaceous life forms, less often shrubs, softwood trees and lianas, the latter include most African species.

Nettle leaves 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 (dotted, rod-shaped, oval, sickle-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 located on the shoots crosswise opposite, in more advanced forms, the leaf arrangement can change to two-row, due to the reduction of one leaf in each pair of opposite leaves. There are many intermediate stages along the way 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 - anisophydlia - the development in one node of leaves of unequal size, and sometimes in shape.

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

The evolution of the family went mainly along the lines 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 also 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 the gynoecium, its perianth is completely reduced, less often an undivided perianth develops.

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

Nettle fruits are small, dry (nut-like), but in some species they are surrounded by a juicy cover from a fleshy calyx that has grown after flowering, which makes the fruit look like a drupe or berry.

Nettles bear fruit profusely, and in some species seeds can develop asexually as a result of apomixis. For example, in a number of species of elatostema (Elatostema acuminatum, E. sessile) there are almost no male flowers, however, female flowers produce fruits with full-fledged seeds. Observations on seed formation showed that in these plants the micropyle overgrows long before the maturation of the embryo sac and the embryo arises from an unreduced ovum without pollination and without fertilization.

In most nettles, the most common method of fruit distribution is zoochory, however, in a number of species of elatostema and Pilea (Pilea), the fruits are peculiarly catapulted, and the role of the catapult is played by staminodes. During the pollination of flowers, staminodes are barely noticeable, and only by the time of fruiting do they significantly increase in size. At this time, the staminodes are bent inward and support the fetus 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 off at a distance of 25-100 m from the mother plant. However, in most stinging nettles, zoochory remains the most common way of fruit dispersal.

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

The family is usually subdivided into 5 tribes: nettle proper (Urticeae), prokris (Procrideae), bemeria (Boehmerieae), forskaolee (Forsskaoleae) and posttennitsa (Parietarieae).

According to the number of species in the tribe, the genus nettle (Urtica) predominates, containing approximately 50 representatives of the nettle tribe, which unites burning plants, are the most well-known in the family. The Latin name of the tribe Urticeae (as well as Urtica, Urticaceae and Urticales), derived from the word uro - burning, is given to it for the many burning hairs covering the leaves and stems of plants. Stinging nettle hairs have stinging cells (up to 100 stinging cells per 1 mg of its mass), containing a caustic liquid of complex chemical composition; it contains histamine, acetylcholine, formic acid. The burning hair looks like a capillary tube ending in a small rounded 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. As a result, there is a painful burning sensation - a nettle burn.

Representatives: nettle (Urtica), laportea (Laportea), girardinia (Girardinia), urera (Urera).

Prokris tribe (Procrideae)

The largest tribe in the family, includes more than 700 species of herbaceous, rarely succulent plants, usually living under the canopy of the tropical rainforests of Southeast Asia, in wet habitats, near streams, in rock crevices and gorges.

Representatives: Pilea (Pilaea), Elastosoma (Elastosoma), Pelionia (Pelionia).

Tribe Bemeriaceae (Boehmerieae)

Pantropical tribe, uniting 16 genera and about 250 species of herbaceous plants with large serrated, oppositely crossed leaves. Inflorescences develop in leaf axils. The tribe contains many spinning plants with very long fibers.

Representatives: ramie (Boehmeria), pipturus (Pipturus), mautia (Maoutia), puzolzia (Pouzolzia), leucosyke (Leucosyke).

Tribe Forskaleae (Forsskaoleae)

The most archaic and interesting from an evolutionary point of view, a group of nettles, very specialized. An analysis of the ranges suggests that all three genera have existed for at least 75 million years, and were part of the Cretaceous subtropical flora of the coasts and islands of the ancient Tethys Sea.

Representatives: australina (Australina), drogetia (Drougetia), forscalea (Forsskaolea).

Tribe parietarieae

A small (5 genera and about 30 species) group, the most advanced in the family, includes herbaceous and shrubby plants with entire, mostly alternate leaves. There are many pioneer plants and weeds among the walls. Distribution - Southern Europe, Mediterranean, Transcaucasia.

Representatives: parietaria, zhesnuinia (Gesnouinia), gemistilis (Hemistylis), russelia (Rousselia), soleirolia (Soleirolia).

Comparison of sanitary and microbiological indicators in intensive care units of KKB No. 1

For the cultivation and primary identification of enterobacteria, Ploskirev bactoagar, bismuth-sulfite agar, Endo agar, Levin's medium, and others were used. Colonies of representatives of the genus Salmonella were black...

Biological characteristics of some medicinal plants of the Lamiaceae family

Most labiales are herbs and shrubs. However, among them, especially in the tropics and subtropics, there are many shrubs; there are also labiales - trees and creepers ...

Species of the buttercup family (ranunculaceae)

Most buttercups are perennial herbs, but among them there are annual or biennial herbs, as well as subshrubs. Rhizome mostly sympodial (rarely monopodial); it is formed if the internodes of new underground shoots are shortened ...

Leuzea safflower-like and its use in medicine

Rhizomata cum radicibus Leuzeae Rhizomata cum radicibus Leuzeae Leuzea leaves - Folia Leuzeae Leuzea safflower - Rhaponticum carthamoides (Leuzea carthamoides) Aster family - Asteraceae Fig.1...

Roots and rhizomes of madder - Rhizomata et radices Rubiae Madder dyed - Rubia Tinctorum L. Georgian madder - Rubia iberica Fisch. ex D.C. Family Rubiaceae - Rubiaceae 3.1...

Medicinal plants and medicinal plant materials used in medicine for urolithiasis

Nettle order (Urticales)

Elm family (Ulmaceae) (I. A. Grudzinskaya)

The elm family combines two fairly separate groups of woody plants, differing in the structure of flowers, pollen grains, fruits, embryos, leaf anatomy, the main chromosome number, the composition of chemicals, etc. These two groups are usually given the rank of subfamilies or, less often, independent families (Grudzinskaya, 1967 ). In this edition, we accept them as subfamilies of elm (Ulmoideae) and carcass (Celtidoideae).

In the elm family, only woody plants with simple alternate leaves and rapidly falling stipules. Their axillary inflorescences combine small wind-pollinated flowers with a simple calyx perianth, divided into 4 - 5 (9) lobes; they are opposed by approximately the same number of stamens. The ovary is superior, single-celled, developing into a one-seeded, indehiscent fruit.

The elm subfamily is a small homogeneous group, the most isolated and most primitive in the order of nettles. It unites 6 genera, which include about 50 species of woody plants. The central place among the elm belongs to the genus elm (Ulmus), which includes more than 75% of the species of the subfamily, distributed from the temperate to tropical zone of the northern hemisphere.

In all genera of the elm subfamily, even true tropical ones, young emerging shoots are covered with bud scales. The flowers are bisexual or bisexual and male, the stamen filaments in the buds are straight. In the order of the nettles, only in the elms it is clearly noticeable that their gynoecium is formed by two fused carpels: in one of them the ovule develops, the other is reduced and remains sterile. The upper parts of the carpels do not grow together and bear stigma surfaces on the inner side. There is no column. Ovary unilocular, flattened.

The simplicity of the structure of the elm flower, like the whole order of nettles, is secondary. Its simplification was due to the reduction, fusion and loss of individual organs (parts of the stamens, corolla, calyx lobes and carpels). This can be judged by the preservation of a large number of flower parts in primitive groups of species, as well as by the remains of the vessels of the conducting system of no longer existing organs. Reduction processes in flowers probably began a very long time ago. In any case, judging by the fossil prints, elm flowers, whose age is determined at 20-30 million years, already had a structure similar to the modern one.

In all genera of elm, the ovaries are similar in structure, but their transformation into fruits is extremely specific for each genus, as a result of which the fruits themselves differ sharply in shape and structure (Fig. 128). The fruits of our elms and holoptels (Holoptelea) are winged achenes, but some elms develop wingless fruits. Nuts are characteristic of the rest of the elm genera: in the Brazilian phyllo-stylon (Phyllostylon brasiliense), they end in two narrow, unequal wings with ribs along the outer edge and with stigmas along the inner; David's Hemiptelea (Hemiptelea davidii) nuts are slanting, one-winged, swollen, humpbacked; the nuts of the Zelkova species do not have wings, and the water gliders (Planera aquatica) have semi-fleshy comb-like outgrowths instead of wings. The fruits are well adapted to being carried by the wind. This is facilitated by their wings, large air cavities in the intercellular spaces of the pericarp, a small mass and flattened shape of the fruit, often bordered by cilia, or an enlarged cavity of the seed nest. Zoochory is not of great importance here, although animals willingly eat elm fruits.

In a temperate climate, with a sharp change in seasons, elms are usually deciduous summer-green plants; in the subtropical and especially tropical zones, semi-deciduous, less often evergreen forms appear among them. Tropical semi-deciduous holoptelea and phyllostylon usually shed their leaves before flowering, but the duration of their stay in a leafless state fluctuates sharply from year to year and is associated with living conditions and with the age of the tree. In Cuba, in some years, young phyllostylon plants retain most of their foliage all year round, and in dry years, mature trees stand without leaves for about 3 months. Zelkva and hemiptelea are deciduous plants, and the elm genus is represented by a whole variety of forms, and from north to south, semi-deciduous species are added to its deciduous species, and in the tropics also evergreens.

If we trace the seasonal development of elm species from the temperate to the tropical zone, we can notice very curious patterns not only in the nature of deciduousness, but also in the rhythm of flowering. In elms of the temperate zone, flowers are formed in buds already at the beginning of summer, but they bloom only the next year and, thus, are in buds for about 10 months. Elms bloom in early spring while still in a leafless state. To the south, in Central Asia and the Mediterranean, elms bloom in February and even in January, and the period of flowers in buds is reduced to about 7 months. In the subtropical regions of America, Japan and China, there are semi-deciduous elms that bloom in autumn of the same year. Their flowers are in buds for only 3-4 months, inflorescences appear in autumn, when many leaves have not yet fallen. Part of the inflorescences appears in the axils of these leaves, which gives the impression of leafy flowering shoots. Finally even further south, in the tropics of Southeast Asia, evergreen elm lanceolate(Ulmus lanceifolia) blooms in early summer, apparently immediately after the end of flower formation; the residence time in the buds of its flowers is reduced to a minimum.

The inflorescences of elms, holoptels, phyllostylons, and gliders are leafless and form in specialized buds, which usually do not bear the rudiments of true leaves. On the other hand, flowering shoots of zelkova (Fig. 129) and hemiptelea (Fig. 130) species do not have a strict specialization. Their flowers are formed together with the leaves in the same buds, bloom in spring - early summer, immediately after the leaves unfold; fruits ripen only at the end of summer or autumn. In elms, as in gliders, the formation of fruits lasts about a month, and already in late spring - early summer, the fruits ripen and fall off.

Elm seeds have a flat, straight embryo, protected by a three-layer seed coat (the fourth inner single-row layer is formed by endosperm cells) and a four-layer membranous pericarp. On a moist substrate, the seeds germinate in a few days without a dormant period. Developed seedlings differ sharply from the shoots of adult plants. This phenomenon, known in many plants, is called heteroblast development. In elms, it lies in the fact that their usual shoots have a bilaterally symmetrical structure: the leaf blades are asymmetrical, the stipules are not the same in shape and size, the leaf arrangement is two-row-alternate. An apical bud never forms on the shoots, and after the growth of the shoot stops, its upper part dies off. In contrast, in seedlings of elms, the main shoot is radially symmetrical: its leaf blades are more or less symmetrical, the stipules are the same, and the leaves are located on the shoot oppositely across. At the top of such a shoot, a terminal bud is formed. True, special bud scales do not arise in this case, and the stipules of the upper leaves take over the protection of the apical growth cone, as is typical of many tropical plants that do not form bud scales. These stipules-scales remain on the shoot until the next spring, that is, they live much longer than the leaves, while ordinary stipules in elms fall off much earlier than the leaves - at the beginning of summer.

The originality of the main shoot of the seedling also lies in the fact that it develops according to the monopodial type and is formed by the apical (by position) meristem. All subsequent shoots, including those continuing the main axis of the plant (trunk), arise due to the activity of the axillary (lateral) meristem; the apical meristem in elms usually dies shortly after the formation of the terminal bud of the shoot. The shoot formed from the upper lateral bud grows most rapidly and, overtopping the maternal shoot, becomes axial. This repeated topping from year to year is a characteristic feature of the growth of the trunk and branches of elms, which makes it possible to classify them as typical sympodial plants.

The shoots of some elms attract attention with peculiar cork outgrowths, especially characteristic of young plants growing in dry, well-lit places. Outgrowths of a completely different type sometimes appear on the trunks of old small-leaved elm trees in xerophytic formations of East Kazakhstan. These are burls - huge influxes of compacted, unusually strong wood. An interesting modification of shortened shoots, turned into real thorns, is characteristic of hemiptelea (Fig. 130) - the only thorny tree among the elms.

Elm leaves, even on the same shoot, can vary dramatically in size and shape. This allows them to be located most favorably in relation to the light - in one plane - in the form of a continuous mosaic cover (leaf mosaic). The venation of elm leaves is typical pinnate, marginal, with a powerful midrib and short laterals, usually ending in the teeth of the leaf. The surface of the leaves is often pubescent with soft or coarse hairs, and in some species of elms, the leaves from below are covered with tiny glandular hairs: dotted (in our birch bark) or rod-shaped (in the Himalayan hairy elm - U. villosa). The color of these glandular hairs changes as the leaf ages: from colorless in young developing leaves, orange in early summer, red in summer, to almost black in autumn.

The root system of the elms is powerful, with separate deep roots and a mass of superficial ones. Large trees sometimes develop plank-like roots that perform a supporting function and are so characteristic of trees in tropical rainforests. These roots reach a height of 1.5 m at the point of departure from the trunks of tropical holoptels. Elms of the temperate zone (smooth elm - U. laevis, valley elm - U. japonica) usually have a height of 30 - 50 cm, but their structure is the same as that of tropical trees. However, according to I. V. Grushvitsky (1955), individual trees of the valley elm in the south of Primorsky Krai have one and a half and even two-meter plank roots.

Representatives of all studied elm genera are mycorrhiza-forming plants, especially abundant mycorrhiza occurs on birch bark roots, which are often covered with peculiar mycorrhizal sheaths.

The root system is of great importance in the vegetative reproduction of elms due to the formation of root offspring. In the hexaploid hemipteleia of David, which produces many seedless fruits, the rhizomatous type of renewal often predominates over the seed type. Often propagated by root suckers and birch bark.

Information about the life expectancy of elms is contradictory, but elms and zelkovas are reliably known to have lived up to 500 years (the age of individual trees of the hornbeam zelkova - Zelkova carpinifolia - in Talysh is determined at 800 - 850 years). Such centenarians often reach the maximum sizes for these species: up to 35–40 m in height and 3–4 m in diameter. mexicana) and Southeast Asia (lanceolate elm); Holoptelea integrifolia reaches large sizes in the tropical forests of India. Representatives of other elm genera are small trees, 4-18 m high.

The modern range of the Elm subfamily covers a vast territory, within which most genera have a disjunctive (disjunctive) distribution, and the appearance of these disjunctions is usually associated with the Tertiary or Upper Cretaceous.

Paleobotanical data indicate that in the Miocene, in the temperate and warm temperate floras of the Tertiary Boreal region, corresponding to the territories of modern Eurasia and North America, elms were widespread and represented by a wide variety of forms (elm, zelkova, and glider genera). Breaks in the modern ranges of the tropical genera Holoptelea (Western India - Equatorial Africa) and Phyllostylon (Brazil - Caribbean floristic region) confirm the antiquity of these genera and suggest their wider distribution in the past. Even the monotypic genus Hemipteleus, whose modern range is limited to a small area in East Asia, was distributed in the Miocene - Pliocene in Central and Southern Europe.

Water glider - the only modern representative of the glider genus - a relic plant, occasionally found in Florida and adjacent areas of southeast North America. It grows in ancient forests dominated by swamp cypress (Taxodium distichum), the soil of which is covered with water for most of the year.

Clearly relic is the modern range of zelkova (Japan - regions of South and Central China - Transcaucasia - regions of Western Asia - the island of Crete).

Among the elms, only the genus elm has an unbroken (continuous) extensive range, but within it there are curious disjunctions in the distribution of closely related species of one section. Thus, our European smooth elm (Ulmus laevis) is separated by a transatlantic disjunction from the closely related American elm (U. americana). Morphologically, these species are almost indistinguishable, but have different degrees of ploidy: European - diploid (2n = 28), American - tetraploid (2n = 56). The disjunction is similar between diploid species: the European mountain elm (U. glabra) and the American red elm (U. rubra).

In our country, representatives of the elm genus are known under the names of elms, elms, birch bark, elms. They are usually recognized by their double-toothed, unequal-sided leaves and lionfish fruits that appear in early summer.

In the broad-leaved forests of the European part of the USSR, the most common are smooth elm and mountain elm - large trees reaching a height of 25 - 27 m. Both species have a wide latitudinal range of distribution, it is especially large for smooth elm. Stretching from the shores of Lake Onega to the deserts of the Caspian Sea, its range covers the zone of semi-deserts, steppes, forest-steppes, broad-leaved forests and dark coniferous taiga.

In the forest-steppe zone, birch bark (U. campestris) is more common - a relatively small edged tree, often attracting attention with cork growths on the branches.

Along the river valleys of the Far East, in broad-leaved and cedar-broad-leaved forests, huge white-bark valley elms are not uncommon, here small trees of lobed elm (U. laciniata), more common in the mountain forests of Primorye, grow. Large-fruited elm (U. macrocarpa, Fig. 131) and small-leaved elm are also common in the Far East and Transbaikalia - pioneer species of open habitats, sometimes forming xerophytic light forests.

Large-fruited elm is a small tree, often developing on rocks and screes as a shrub-like plant, abundantly bearing fruit even at a height of 50-70 cm. Its lionfish are the largest (up to 3-4 cm in diameter), cork growths on young shoots grow in the same plane, which is why shoots also look winged.

Small-leaved elm (U. pumila) is of great importance in landscaping and protective plantings in arid countries of almost all continents. Its natural range extends from the mountains of the Western Tien Shan through the deserts of Mongolia and China to Transbaikalia and the Far East. In the deserts of the Gobi, it is often the only tree species. Here it is a low-growing tree (2 - 6 m high) with a small crown and a powerful trunk, up to 1 - 1.5 m in diameter. In East Kazakhstan, in the Ili River basin, centennial elms have a height of 8 - 12 m, they reach the same height in the floodplains of the rivers of the Far East and Transbaikalia, but in cultivation, especially along ditches in Central Asia, they can exceed 25 m in height and develop a powerful spreading crown.

Not even a hundred years have passed since the beginning of breeding of this species outside its natural range, but now its "cultural" range encircles the entire northern hemisphere, capturing some parts of the southern hemisphere (regions of Australia and Argentina). In the Great Plains region (North America), the small-leaved elm behaves as a native and is included in the local floras. In our country, he is a favorite breed in the landscaping of southern cities and towns along the entire length from the eastern to the western borders.

Representatives of the elm genus have existed on Earth for tens of millions of years and, judging by fossil finds, have not changed in any significant way over this period of time, despite repeated and sometimes abrupt changes in living conditions. This indicates a huge adaptive (adaptive) potential, which is visible at the present time in terms of the breadth of ecology and the modern distribution of the genus. Being characteristic components of broad-leaved forests, elms also grow in deserts and beyond the Arctic Circle, along drying rivers (ueds) in North Africa and near the equator, in Sumatra and Sulawesi, in the tropical forests of Yunnan, in the mountains of Mexico and in the Himalayas.

Elms are unpretentious plants that tolerate a lack of moisture and excessive flowing moisture, they are able to grow on saline soils, stony placers and rocks, on riverine sands and pebbles, put up with a lack of heat in the north and its excess in hot deserts, with fluctuations in the water level of rivers and lakes, along the banks of which these trees are most common. And it is precisely the areas with extremely variable environmental factors, to some extent unfavorable for the development of the forest and the growth of trees in general, that are most common for cenoses with a predominance of elms.

In flat broad-leaved forests, which are optimal for the development of most of our elms, they are found only in a small admixture with the main species, firmly taking the place of assectator (additional) species. Even in floodplains of large rivers, where elms often form areas of pure stands, their growth is usually associated with a narrow strip, characterized by the most variable water regime, at the junction of floodplain oak forests and thickets of willows or alders. In dry years, this strip is unfavorable for the development of willows, in wet years - for oak.

Elm has long been used for various purposes. Mucous secretions of elm bast have bactericidal properties, they, like seeds, are used in folk medicine. Valuable industrial oil is also obtained from elm seeds. The immature fruits of the small-leaved elm in China are eaten as a salad.

In a number of mountainous regions of Asia and Transcaucasia, branches of elm and zelkova are harvested for livestock feed. In the landscapes of these mountainous countries, and especially in the Himalayas, mutilated elm trees are not uncommon, the branches of which are cut off almost to the top of the trunk.

Elm wood has great economic value. Already in fossil human settlements in Europe, houses built from elms were found. In the last century, elm and zelkova wood was widely used as a building material, especially for buildings in the water: on piles, in shipbuilding, etc. It also goes to the production of furniture and plywood.

At present, when the reserves of elm wood in natural plantations have significantly decreased, elms bring the greatest benefit as landscaping species and invariable components of protective plantations. The speed of growth of elms, their decorative effect, undemanding to soil nutrition, the ability to withstand lack of moisture and strong winds, significant temperature fluctuations and smoke in the air have long made them a favorite tree in urban landscaping in the countries of the northern hemisphere.

Elms are cultivated on the streets, in gardens and parks throughout Eurasia (small-leaved elm, smooth elm, mountain elm, valley elm, birch bark), in Africa (small-leaved elm, grayish elm), in North America (American elm, small-leaved elm, Thomas elm , red elm). In addition to the usual species, a number of peculiar decorative forms fixed in culture are also used in landscaping. These are weeping and pyramidal elms, as well as the famous thick-crowned elms - dense elm (U. densa) and Androsov elm (U. androssowii), decorating the streets, gardens and parks of the republics of Central Asia, certain regions of Transcaucasia and Western Asia. Their unusually dense spherical or oblong crown almost does not let in the sun's rays and shelters from the sun at any time of the day, which makes them exceptionally valuable in areas of hot deserts. Dense-crowned species are characterized by very slow growth, and therefore they are usually grafted onto ordinary birch bark or small-leaved elm trees.

Over the past 60 years, a disease has spread among the elms, called the Dutch disease after the place of its discovery (see pp. 129, 130 of the second volume of the Life of Plants). All types of elms are susceptible to it (only small-leaved elm is stable). The most effective measure to prevent the development of the disease is the injection of antibiotics into the stem of the plant.

The frame subfamily is evergreen, semi-deciduous or deciduous trees, less often evergreen climbing vines, common in the tropics and subtropics of all parts of the world. Of the 9 genera that make up the subfamily (about 80 species), only one monotypic genus pteroceltis(Pteroceltis) does not go beyond the warm temperate zone, the remaining 8 genera include mainly tropical plants, and only some of their species grow in areas of a temperate warm climate.

According to the majority of morphological features and the general level of development, skeletons are a much more specialized group than elms.

The subfamily is dominated by species with unisexual flowers, although a small percentage of unisexual flowers is common in some. In the warm-temperate zone, skeleton plants are represented only by monoecious plants, in the tropics - both monoecious and dioecious, and even within the same species, one can see different degrees of differentiation of trees according to the predominance of female or male flowers. Hetacma spinous (Ghaetacme aristata), for example, in the tropics of East Africa almost always has dioecious flowers, and in South Africa it often develops as a monoecious plant. All transitions from monoecious to dioecious were noted in the eastern trema (Trema orientalis), Lamarck's trema (T. lamarckiana), Durand's carcass (Celtis durandii), etc.

Male skeleton flowers are collected in multi-flowered inflorescences in the axils of scaly leaves, female ones are located higher along the shoot in the axils of green leaves, 1-3 each, or in complex multi-flowered inflorescences.

Unlike the elm subfamily, which are characterized by dry fruits, all frame fruits have one type of fruit - a drupe (Table 36), but its structure, size and shape are varied (Fig. 132).

The seeds of skeletons are usually rounded, the embryo is bent across, folded across or rolled into a spiral; in mature seeds, the endosperm is preserved; it surrounds the embryo and fills the depressions in its folds; the seed coat is always single-layered, the pericarp is 3-4-layered.

The main chromosome number in skeletons is the same as in cannabis (x=10). Polyploidy is characteristic, with some species reaching a very high degree of ploidy ( trema amboinskaya- Trema amboinensis - 16-ploid!).

The leaves of most skeletons have 3 distinct basal veins, which brings their venation closer to the palmate type. In most South American carcasses, on the underside of the leaf blade, as a result of the growth of the bases of these veins (probably under the influence of mites settling in them), specific structures similar to swollen pockets develop. Finally, skeletal leaves are characterized by rounded cystoliths and a diverse nature of pubescence (up to 4 types of hairs, including glandular ones, develop on one leaf in Lamarck's Westind trema).

The main genera of the skeleton subfamily are 2 pantropical genera: skeleton (Celtis, Table 36) and trema (Trema), including more than 85% of all species. The skeleton is not only the largest (more than 50 species), the most polymorphic, but also the most widespread genus. Its range encircles the globe with a huge strip, the northern border of which fluctuates around 40 ° north latitude, passing through Japan, continental Asia, the Caucasus, southern Europe and North America; the southern one runs along about 35 ° south latitude through New Caledonia, Eastern Australia, the Cape region of Africa and southern Argentina. Despite the great polymorphism, the frameworks retain a single type of structure of flowers, fruits, and leaves within the entire range. Frame species are either diploid (number of chromosomes in somatic cells 2n = 20) or tetraploid (2n = 40) plants. The latter include all types of the USSR, also common in the Mediterranean: Caucasian frame (C. caucasica), bare frame (C. glabrata), southern frame (C. australis), Tournefort frame (C. tournefortii). These are deciduous, summer-green trees with smooth light gray bark and a spreading crown, sometimes reaching a height of 30 m, with a trunk up to 3 m in diameter, or growing in small trees and acquiring a shrub-like shape in adverse environmental conditions (bare frame and Tournefort frame).

Carcass species occupy various ecological niches and grow in diverse communities. The Caucasian frame and the Tournefort frame are more common in dry forests and arid woodlands, in the lowlands and in the mountains, often rising to a height of 2500 - 2800 m above sea level, usually in places remote from the sea. On the contrary, the southern frame and the bare frame grow mainly in coastal areas. All these species live on open rocky slopes and in gorges, among rocks, on screes, along the rocky banks of small rivers or along slopes to the sea.

The frameworks of tropical countries are richly represented and varied, where, along with deciduous and semi-deciduous, evergreens are also common, and in many of them bud scales do not develop and the rudiments of the emerging shoot are covered only by stipules of the covering leaf.

The frameworks of Australia and especially New Caledonia are very peculiar, distinguished by whole-extreme thick succulent leaves. In the crowded carcass (C. conferta), which grows in the coastal zone and is not uncommon among mangroves, the leaves are collected at the top of the shoot and are sometimes opposite. In the tropics of Asia, Africa and South America, carcasses are included in the communities of evergreen lowland rainforests (White's carcass - C. wightii, Mildbred's carcass - C. mildbraedii), as well as mountain forests (Duran's carcass, etc.). Tropical frames also grow in dry evergreen forests, often forming deciduous woodlands (African frame - C. africana, whole-leaved frame - C. integrifolia).

In the forests of the New World tropics disturbed by logging, evergreen climbing vines intensively develop: iguana frame (C. iguanaea), prickly frame (C. spinosa), Bolivian frame (C. boliviensis). In the first years of life, these frames grow as upright trees or shrubs (1.5 - 5 m high), later their upper branches intensively lengthen and, clinging to nearby trees and shrubs with bent thorns, use them as a support. The plant thus turns into a climbing vine and retains this appearance until the end of its life.

In warm-temperate climates, the carcasses bloom in spring, almost simultaneously with leafing out. Their male flowers open a few days earlier than bisexual and female ones. The flowers are pollinated by the wind, and although they are visited by insects, entomophily is not of great importance, since the pollen is devoid of the characteristic features of the grains of entomophilous plants and, at the moment of straightening the stamen filament, is instantly spilled into the surrounding space.

The fruits ripen in autumn, by which time the inner part of the pericarp (stone) becomes very hard, and the powdery outer layer becomes bright yellow (bare frame) to almost black (southern frame). The drupes of carcasses are readily eaten by birds and are also spread by them.

Seeds of carcasses usually germinate in the spring of the next year, seedlings, like those of elms, develop according to the heteroblast type and in the first year pass to sympodial branching.

Frames grow relatively slowly and live for a long time (up to 200, and according to some sources - up to 600 years). However, at present there are few old large carcass trees. The high value of its wood and its growth mainly in sparsely forested areas entail regular felling of young trees. After felling, trees recover relatively quickly due to intensive coppice (from the stump) renewal.

The frame is often also called a stone tree for its hard, strong, heavy (density 0.78) wood. Despite a number of valuable properties, it is still not of great industrial importance and is currently used mainly for small handicrafts and decorative items. In arid countries, carcasses have long been bred, these trees are also loved in Central Asia, the Caucasus and the Crimea, where they are often used in landscaping towns and cities, as well as in protective plantings.

The genus Pteroceltis, common in Central China, is closest to the frameworks. Its only species was described by the Russian botanist K. I. Maksimovich and named after the collector of this plant - Tatarinov's pteroceltis (Pteroceltis tatarinovii). The very peculiar winged fruits of Pteroceltis are often considered as a transitional link between the wingless fruits of the skeleton and lionfish of the elm, which gives reason to bring together the taxa themselves, but the similarity of the fruits is only external - this is an example of convergent development. The fruit of pteroceltis is a real spherical drupe with a very thick, strong endocarp, the outgrowths of which form woody wings, thinning towards the edge. At the top, the wings are widely spaced, between them and isolated from them, in contrast to the elms, there is a column with two stigmas (Fig. 132). Pteroceltis and, according to other characteristics, is a typical representative of the skeleton subfamily: it has unisexual flowers, drupes with a 4-layer pericarp, a single-layer seed coat, a folded embryo, 3 veins at the base of the leaf, the main chromosome number x is 20. Pteroceltis usually grows along rivers and in rocky places at relatively low altitudes (up to 1200 m above sea level). Most often these are trees 12-17 m high, with a spreading crown and short thick trunks up to 1.5 m in diameter.

Very interesting and apparently monotypic genus hetakma(Ghaetacme) is common in Madagascar and in equatorial and South Africa. Hetakma spinous develops as a small tree or shrub 3-7 m high, it has shiny leathery leaves, sometimes ending in a thin point - a thorn, unisexual flowers and small fruits with a hard stone. This species is very polymorphic and includes plants with monoecious and dioecious flowers, is represented by strongly pubescent and bare forms, prickly and without spines, its leaves are serrated, spiky-toothed or entire. Hetakma spinosa grows in a zone transitional from forest to savannah, occurs in deciduous, semi-deciduous forest and shrub formations, in sclerophilic gallery forests, where sometimes, together with other plants, it forms impenetrable thorny thickets, so characteristic of these countries.

In tropical countries, the genus Trema is widely known, represented mainly by evergreen trees, sometimes shrubs, 2–16 m high, distributed on all continents and many islands from lowlands to 2500 m above sea level. They have a sparse spreading crown, branched axillary inflorescences, bearing numerous small, usually unisexual flowers. The fruits are small fleshy drupes, bright yellow-orange in Lamarck's trema and dark in oriental trema and small-flowered trema.

Species of the genus Trema are difficult to distinguish, and there are still disagreements among taxonomists regarding their volume and number. Apparently, there are no more than 20 species in the genus, all of them are close and form a polyploid series with the number of chromosomes in somatic cells from 20 to 160.

Trema - fast growing unpretentious plants that live on the edges of evergreen and semi-deciduous forests of plains and mountain slopes, are common along roads and clearings. Trema species are common components of secondary plant formations in the tropics, in particular, characteristic representatives of peculiar secondary formations with tree-like ferns that develop after fires and logging in the place of rain mountain tropical forests. In Cuba, this is a community of small-flowered trema (Trema micrantha) and cyathea tree fern (Cyathea arborea), with a continuous cover of tailed bracken fern (Pteridium caudatum). Similar plant formations are also characteristic of the tropics of the Old World. In Java, for example, there are communities of eastern trema and dirty cyathea (Cyathea contaminans), in the undergrowth there is an inulo-leaved vine (Eupatorium inulifolium).

Trema is so far the only genus in the order of nettles, in which a symbiosis with nitrogen-fixing bacteria has been found. Nodule bacteria from the Rhizobium group have recently been found on the roots of trema orientalis, which gives reason to classify it as a soil-improving plant. Perhaps partly due to this property, trema is readily used on coffee and cocoa plantations to create a sparse canopy under which these crops are planted.

It is very close to the genus Trema and it is difficult to distinguish from it a small genus of Parasponia (Parasponia), common on the islands of Oceania. Representatives of both genera are typical pioneer plants, noted as the first settlers of lava flows (Bali Island).

The genus Afanantha (Aphananthe) has a discontinuous range covering distant regions of tropical and warm temperate Asia, including Malesia, areas of the Solomon Islands, Eastern Australia, Madagascar and Mexico. These huge disjunctions speak of a wider distribution of the afanant in the past.

In the tropics of South Asia, Indonesia and Oceania (mainly on tropical islands), the genus Gironniera (Gironniera) is widespread, represented by huge evergreen trees of tropical rainforests (G. ceItidifolia), or small, up to 16 m high, trees of more dry semi-deciduous formations of the tropics (half-equal Gironera - G. snbaequalis, etc.).

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

Nettles include about 60 genera and more than 1000 plant species, distributed mainly in the tropics. The family is usually subdivided into 5 tribes: nettle proper (Urticeae), prokris (Procrideae), bemeria (Boehmerieae), forskaolee (Forsskaoleae) and posttennitsa (Parietarieae).

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

The evolution of the family went mainly along the lines 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 also 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 gynoeciums, its perianth is completely reduced, less often an undivided perianth develops. Inflorescences of nettles of the primate type, diverse in shape: capitate, paniculate, catkin-shaped. Sometimes they are bisexual and contain one - several female and several male flowers, more often the inflorescences are unisexual.

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

Nettle fruits are small, dry (nut-like), but in some species they are surrounded by a juicy cover from a fleshy calyx that has grown after flowering, which makes the fruit look like a drupe or berry. Urera baccifera, a small tree native to the American rainforests, has a brightly colored calyx that makes the fruit even more like a berry. Similar to berries and reddish-orange inflorescences of Procris species (Procris), the fleshy part of these inflorescences is formed by the receptacle. The reddish-purple mulberry seedlings (Laportea moroides) are very similar to mulberry seedlings or raspberry fruits, however, in contrast to them, the fleshy part of the fruit of this plant arose mainly due to the growth of the pedicel.

Nettles bear fruit profusely, and in some species seeds can develop asexually as a result of apomixis. For example, in a number of species of elatostema (Elatostema acuminatum, E. sessile) there are almost no male flowers, however, female flowers produce fruits with full seeds. Observations on seed formation showed that in these plants the micropyle overgrows long before the maturation of the embryo sac and the embryo arises from an unreduced ovum without pollination and without fertilization.

In most nettles, the most common method of fruit distribution is zoochory, however, in a number of species of elatostema and Pilea (Pilea), the fruits are peculiarly catapulted, and the role of the catapult is played by staminodes. During the pollination of flowers, staminodes are barely noticeable, and only by the time of fruiting do they significantly increase in size. At this time, the staminodes are bent inwards and support the fetus 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 off at a distance of 25 - 100 m from the mother plant. However, in most stinging nettles, zoochory remains the most common way of fruit dispersal.

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

Nettle leaves are simple, as a rule, 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 (dotted, rod-shaped, oval, sickle-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.

Leaves of primitive forms of stinging nettles are located on the shoots crosswise opposite, in more advanced forms, the leaf arrangement can go to two-row-alternate, due to the reduction of one leaf in each pair of opposite leaves. There are many intermediate stages along the way 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 unequal in size, and sometimes in shape of leaves (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, Urticaceae and Urticales), derived from the word uro - burning, is given to it for the many burning hairs covering the leaves and stems of plants. Stinging nettle hairs have stinging cells (up to 100 stinging cells per 1 mg of its mass), containing a caustic liquid of complex chemical composition; it contains histamine, acetylcholine, formic acid. A burning hair looks like a capillary tube ending in a small rounded 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. As a result, there is a painful burning sensation - a nettle burn.

Burns inflicted by tropical representatives of the tribe, especially arboreal laportees, sometimes lead to serious consequences. The stinging action of the strong-burning Laportea (Laportea urentissima), which grows in Southeast Asia, is so strong that it can cause the death of a child. The arboreal laportees of the Philippines are also notorious: the Lusop laporte (L. Luzonensis) and the semi-closed laporte (L. subclausa). Incredibly painful action of the burning hairs of the Australian giant laportee (L. gigas) - a large tree from the tropical rainforests of Northeast Australia; 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 mulberry mulberry, which grows in our greenhouses as a herbaceous plant, and the light-leaved shrub (L. photiniphylla) from the Fiji Islands, from New Caledonia and Australia. Unpleasant burns laporteiznoy (L. aestuans) - a small creeping herbaceous plant of the Antilles. The touch of the herbaceous Girardinia heterophylla, common in Indochina, is very painful.

Burning 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 arboreal laportea, for example, turned out to be harmless to cattle, the leaves of nettles eat snails with impunity, etc. It is not surprising, therefore, to see additional protective devices in plants. Urera berry, for example, in addition to burning hairs, develops many spines on the shoots, in addition, it is one of the few nettles that have milky juice. Laportey and nettles also have milky, but they contain a colorless liquid, and not milky juice, like most mulberries.

The genus predominates in the number of species in the tribe. nettle(Urtica), containing about 50 species of herbaceous plants, and the tropical genus Urera (35 species), represented by different life forms: herbaceous plants, shrubs, softwood trees and lianas, the latter include most African species. In the USSR, of the tribe Urticeae, only nettle species are widespread (Fig. 147). Everyone knows the nettle as a burning weed, but not everyone knows that the 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 beriberi. Nettle seeds are rich in oil, the leaves are successfully used for feeding silkworms, yellow is obtained from the roots, and green paint is obtained from the leaves. Since ancient times, nettle has been known as a spinning plant; in the past, it was a common raw material for making fabrics in a handicraft way. The bactericidal effect of nettle is well known to fishermen, and they use it to preserve fresh fish (the insides of the fish are taken out and stuffed with nettles).

Stinging nettle (U. urens) - a smaller and more burning annual plant (Fig. 147) - is the constant companion of human housing - dioica nettle - is cosmopolitanly distributed, stinging nettle (U. urens) also has a cosmopolitan range. These plants also differ in the nature of the distribution of flowers: in stinging nettle, both male and female flowers are placed on the same plant, in dioecious nettle, usually on different plants. It differs sharply from them in 3 - 5-separate leaves, similar to hemp leaves, hemp nettle (U. cannabina, Fig. 147). Its range passes through the Asian part of the USSR, Mongolia, Japan and China. Another peculiar type of nettle is ball-bearing nettle (U. pilulifera) - a small bluish plant with whole leaves and spherical inflorescences on long legs located in their axils. Its range covers the Mediterranean, in our country it grows in the Crimea and the Caucasus, occasionally meeting in the south of the European part of the USSR.

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

The largest prokris tribe includes more than 700 species of mostly herbaceous, often succulent plants, living mainly under the canopy of tropical rain forests or in moist habitats in semi-deciduous tropical forests - near streams, under rocks, in gorges. The pantropical genus Pilea (about 400 species) predominates in the tribe, uniting herbaceous plants with intraaxillary fused stipules, predominantly 3-lobed perianth in female flowers (Fig. 148) and distinct cystoliths of various shapes on 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 a small (16 - 20 species) paleotropical genus prokris, its representatives, mainly herbaceous or shrubby epiphytes with succulent leaves and stems, grow on the trunks and lower branches of trees. Prokris 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 prokris. These are a small (up to 7 cm high) round-leaved pilea (Pilea rotundifolia), a Japanese pilea (P. japonica), also common in Japan and China, and a perennial herbaceous Mongolian pilea (Re mongolica), growing in Transbaikalia.

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

Pilea small-leaved blooms profusely, its millimeter pinkish flowers (Table 39) open at the same time, and the anthers also alternately crack, suddenly throwing clouds of yellowish pollen into the air. It gives the impression that it shoots pollen, which is why this graceful little saw is called the "artillery plant".

The Bemeriaceae tribe has a pantropical distribution (only a few species enter regions of a warm temperate climate) and unites about 16 genera and about 250 species, mostly herbaceous plants with characteristic large and usually coarsely toothed leaves, located oppositely crosswise. In the axils of the leaves are capitate or catkin-shaped inflorescences. In some tropical bemerias, the filamentous axes of the female inflorescences sometimes reach a length of 50–100 cm and look like lichen beards, more often the flowers are collected on the inflorescence axis in separate spherical heads, which is why the overall inflorescence looks like a string of beads.

There are many spinning plants among the bemeriaceae, and the most valuable of them is 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 various fabrics. The fibers of ramie are several times longer than those of other spinning plants, they reach 500 mm. Rami comes from China, but has long been cultivated in many countries, including the USSR (mainly in Central Asia and the Caucasus), and has not lost its importance in the textile industry. Fibers of green bemeria (B. viridis) and representatives of some other genera of the tribe (pipturus - Pipturus, mautia - Maoutia, puzolzia - Pouzolzia, leukosike - Leucosyke) are also used for yarn.

A small tribe of Forscaoleaceae, consisting of 3 genera, has long attracted the attention of researchers with extremely radiated flowers, outwardly not at all similar to nettle flowers. Their medium-sized few-flowered inflorescences are also peculiar: they are enclosed in a wrapper that imitates the perianth, and look like separate flowers.

This tribe is one of the most specialized in the family and at the same time, undoubtedly, very ancient, as evidenced by the ranges of its genera. The genus Australina (Australina, Fig. 149), for example, is distributed in South Africa, in the mountains of Northeast Africa, in 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. Apparently, the genus Drougetia also has similar connections; at present, its representatives naturally grow in South and East Africa, Madagascar and India.

Completely different ancient connections are shown by the distribution of the genus Forskaolea. Its modern range extends from the Canary Islands through North Africa, South Europe, West Asia and Afghanistan to India and thus covers a number of areas of the ancient Mediterranean floristic sub-realm of Holarctic. It is quite probable that this genus also 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 stennitsa (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 one many-flowered, often with wrappers, 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. Stennitsa, usually tender herbaceous plants, sometimes lignified in the lower part, grow in damp places in shady areas, among rocks and stones; they often appear on scree, along mountain slopes they reach a height of 3000 m above sea level (Central Asia). Their range covers mainly the temperate regions of Eurasia, but the weak wall wall (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 in a number of countries, the weak wall was introduced as a result of human activities.

There are many pioneer plants among the walls, and weeds are not uncommon. Their seeds are usually spread by animals. Ants spread the seeds of the lusitanian wallflower (P. lusitanica), 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 stencils are widespread, they grow in the south of the European part, in the Caucasus, in Central Asia and in the Far East (medical stencil - P. officinalis, Lusitanian stencil, Jewish stencil - P. judaica, mosquito-leaved stencil - P. alsinifolia and stennitsa small-flowered - P. micrantha, which some researchers identify with weak wall).

In the Ancient Mediterranean floristic sub-kingdom, the remaining 4 genera of the tribe are also common, and the tree-like forms of the representatives of the genus Hemistilis (Hemistylis) also correspond in tropical America (in the Antilles and in the northern regions of South America) , growing in the Antilles, herbaceous Russelia (Rousselia humilis) in the Mediterranean of the Old World is replaced by grassy soleirolia (Soleirolia soleirolii).

Soleyroliya is a small climbing plant with densely seated small rounded leaves and single flowers, the wrappers 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 settle vegetatively and cover the free territory with a green decorative carpet.

FAMILY NETTLE - URTICACEAE

Nettles include about 60 genera and over 1000 species plants found mainly in the tropics.

The main difference of nettles in the order system is the orthotropic and basal or almost basal ovule, direct shovel-shaped embryo and the predominance of grassy life forms , less often shrubs , trees with soft wood and creepers, the latter include most African species.

Leaves stinging nettles are simple, as a rule, 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 (dotted, rod-shaped, oval, sickle-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 located on the shoots crosswise opposite, in more advanced forms, the leaf arrangement can change to two-row, due to the reduction of one leaf in each pair of opposite leaves. There are many intermediate stages along the way 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 - anisophydlia - the development in one node of unequal in size, and sometimes in shape of leaves.

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

The evolution of the family went mainly along the lines of simplifying the structure of organs and reducing their parts. The features of reduction in stinging nettles are especially pronounced in flower: the gynoecium has completely lost the dimerism of the structure, the number of flower parts can also 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 the gynoecium, its perianth is completely reduced, less often an undivided perianth develops.

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

Fruit nettles are small, dry (nutty), but in some species they are surrounded by a juicy cover from a fleshy calyx that has grown after flowering, which makes the fruit look like a drupe or berry.
Nettles bear fruit profusely, and in some species 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-fledged seeds. Observations on seed formation showed that in these plants the micropyle overgrows long before the maturation of the embryo sac and the embryo arises from an unreduced ovum without pollination and without fertilization.

In most stinging nettles, the most common distribution method fruits is zoochory, however, in a number of species of elatostema and pilea ( Pilea) the fruits catapult in a peculiar way, and the role of the catapult is played by staminodes. During the pollination of flowers, staminodes are barely noticeable, and only by the time of fruiting do they significantly increase in size. At this time, the staminodes are bent inward and support the fetus 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 off at a distance of 25-100 m from the mother plant. However, in most stinging nettles, zoochory remains the most common way of fruit dispersal.

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

The family is usually subdivided into 5 tribes: nettle proper ( Urticeae), procris ( Procrideae), bemeric ( Boehmerieae), forskooleic ( Forsskaoleae) and wall-mounted ( parietarieae).

The most well 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, is given to her for the many burning hairs covering the leaves and stems of plants. Stinging nettle hairs have stinging cells (up to 100 stinging cells per 1 mg of its mass), containing a caustic liquid of complex chemical composition; it contains histamine, acetylcholine, formic acid. The burning hair looks like a capillary tube ending in a small rounded 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. As a result, there is a painful burning sensation - a nettle burn.
Burning 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 arboreal laportea, for example, turned out to be harmless to cattle, the leaves of nettles eat snails with impunity, etc. It is not surprising, therefore, to see additional protective devices in plants. Urera berry, for example, in addition to burning hairs, develops many spines on the shoots, in addition, it is one of the few nettles that have milky juice. Laportey and nettles also have milky, but they contain a colorless liquid, and not milky juice, like most mulberries.

The genus predominates in the number of species in the tribe. 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 lianas, the latter include most African species. In Russia from the tribe Urticeae only species of nettles are widespread.

Everyone knows nettle as a burning weed, but not everyone knows that the common stinging nettle (U. dioica) - most useful a 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 beriberi. Nettle seeds are rich in oil, the leaves are successfully used for feeding silkworms, yellow is obtained from the roots, and green paint is obtained from the leaves. Since ancient times, nettle has been known as a spinning plant; in the past, it was a common raw material for making fabrics in a handicraft way. The bactericidal effect of nettle is well known to fishermen, and they use it to preserve fresh fish (the insides of the fish are taken out and stuffed with nettles).
The constant companion of human habitation - stinging nettle - is distributed cosmopolitanly, stinging nettle also has a cosmopolitan area ( 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 placed on the same plant, in dioecious nettle, usually on different plants. Sharply differs from them in 3-5-separate leaves, similar to hemp leaves, hemp nettle ( U. cannabina). Its range passes through the Asian part of Russia, Mongolia, Japan and China. Another peculiar type of nettle is ball-bearing nettle ( U. pilulifera) is a small bluish plant with whole leaves and spherical inflorescences on long stems located in their axils. Its range covers the Mediterranean, in our country it grows in the Crimea and the Caucasus, occasionally meeting in the south of the European part of Russia.
In addition to nettles, in Russia, from this tribe, spiky girardinia is occasionally found ( Girardinia cuspidata) and bulbous laportea ( 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, nettle-like hairs.

Meet to morphological structure of the flower and inflorescence you can on the page "Handbook of the morphology of herbaceous plants" .

And on the website of the Ecological Center "Ecosystem" you can get acquainted with the distribution of species of herbaceous plants by ecological groups and habitats (biotopes) of central Russia:

I Medicinal plants are a source of medicinal raw materials. Dried, rarely freshly harvested parts (leaves, grass, flowers, fruits, seeds, bark, rhizome, roots) of medicinal plants are used as medicinal raw materials. ... ... Medical Encyclopedia

medicinal plants- Ayr marsh. Air marsh. Medicinal plants are a source of medicinal raw materials. Dried, rarely freshly harvested parts (leaves, grass, flowers, fruits, seeds, bark, rhizome, roots) are used as medicinal raw materials ... First aid - popular encyclopedia

Fibrous plant of the nettle family; same as Rami...

J. local A plant of the nettle family that hurts with a sting [sting I 1.], sting 1 .. Explanatory Dictionary of Efremova. T. F. Efremova. 2000... Modern explanatory dictionary of the Russian language Efremova

NETTLE GRASS- Herba Urtica dioica. Stinging nettle (Urtica dioica L) is a perennial herbaceous plant of the nettle family. Properties. Use nettle leaves collected during the flowering of the plant. They include vitamin K, urticin glycoside, tannins and ... Domestic veterinary drugs

A plant from the genus bemeria (Beehmeria) of the nettle family. More often, R. is called snow-white bemeria, otherwise Chinese nettle, B. nivea, or R. white (sometimes R. green B. viridis, or B. utilis is distinguished as a special species). R. perennial ... Great Soviet Encyclopedia

- (Chinese). A genus of nettle that provides top quality spinning fiber. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. RAMI Chinese nettle, delivers high quality spinning fiber. Nettle or ramie…

unchanged; cf. [Malay] Subtropical plant of the family. nettle, with a long and strong fiber (used in the manufacture of ropes and textiles of special strength). * * * Rami is a semi-shrub of the nettle family. Grown in China, Japan, ... ... encyclopedic Dictionary

s; and. Herbaceous plant with stinging hairs on leaves and stems. Burn your hands with nettles. The garden is overgrown with nettles. Stinging k. Shchi from a young nettle. ◊ Deaf nettle. Weedy herbaceous plant with small white flowers and leaves similar to ... ... encyclopedic Dictionary

- (or nettle), nettles, pl. no, female A weed from the nettle family with skin-burning villi on leaves and stems. Burning edge. Nettle soup. ❖ White or deaf nettle is a plant from the mint family, with small white flowers, ... ... Explanatory Dictionary of Ushakov

See ANTIAR. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. ANCHAR Juice of a poisonous tree upas, with which the inhabitants of the Indian archipelago poison their arrows. An explanation of 25,000 foreign words that have come into use in ... ... Dictionary of foreign words of the Russian language