Plants

PLANTS. The relationships and differences between the two kingdoms of organic nature generally stem from the fact that, having common roots and merging at the lowest levels of organization, they subsequently evolved in two different directions. The evolution of animals generally proceeded on the basis of feeding on solid organic food, actively searching for and swallowing it, while plants evolved along the line of passively absorbing dissolved food directly through their outer body surface. Accordingly, animals are equipped with a nervous system, are generally mobile, have more or less compact outlines, and possess cavities opening to the outside (such as the digestive cavity), whereas plants lack a nervous system, are immobile, have a highly developed surface, and do not have similar cavities. However, mobility is sometimes observed even in highly organized plants. Not to mention the mobility of individual organs, such as the leaves of mimosa, in algae, mosses, ferns, and even some seed plants, special cells with free active movement (zoospores and sex cells) are developed during reproduction. A less common but also sufficiently broad characteristic is the source of carbon nutrition. Most plants, unlike animals, have autotrophic nutrition, assimilating CO₂ from the environment due to the presence of chlorophyll (see). However, among plants there are also many heterotrophic ones (see Heterotrophic plants), such as fungi and bacteria. It should be noted, however, that they absorb ready-made organic food in dissolved form osmotically through the outer surface of the body, rather than swallowing solid particles like animals (with the exception of myxomycetes, see). In relation to nitrogen nutrition, plants, even heterotrophic ones, for the most part can assimilate inorganic nitrogen in the form of HNO₃ and KH₃, whereas animals need organic nitrogen in the form of proteins and amino acids. About 300,000 species of plants have been described. They are united into several types that have independent evolution: 1) green algae, 2) diatoms, 3) brown algae, 4) red algae, 5) blue-green algae, 6) bacteria, 7) myxomycetes, 8) fungi, 9) leaf-stem plants. The first eight, as well as lichens related to them in origin, are united under the general concept of lower, otherwise thalloid, or thallophytic plants (about 100,000 species in total) and are contrasted with the ninth type of higher, otherwise leaf-stem, or cormophytic plants (about 200,000 species). Lower plants, very diverse in structural details, are characterized in contrast to higher plants by the overall absence of division of the body, called a thallus or thallus, into stem and leaves. (On lower plants see Algae, Fungi, Bacteria, Myxomycetes, Lichens.) Higher plants in structure correspond to the concept of a normal plant. In them, the following are distinguished: 1) the stem, mostly cylindrical, upward-growing organ, branching and unlimitedly growing at the ends, where buds and the embryonic tissue hidden in them (growth cone) are located; 2) leaves, mostly flat green organs of limited growth, located on the stem and laid down in buds; 3) in most cases, the root - a branched underground organ, unlimitedly growing at the ends, but not having buds here and not bearing leaves. Leaf and root are the main organs of nutrition: the leaf, due to its chlorophyll content, assimilates CO₂ from the atmosphere, while the root osmotically absorbs water and mineral salts (including nitrogenous ones) from the soil. The anatomical structure of the main organs mentioned is generally as follows: on the surface there is a covering tissue in the form of a single-layer epidermis or in older parts - a multi-layered cork, serving to protect the deeper parts from drying out and damage; under it is the main parenchyma of living cells with intercellular spaces between them filled with air (internal atmosphere, communicating with the outside through small openings in the covering tissue). In green organs (for example, leaves) the main tissue is rich in chlorophyll and performs the function of assimilating CO₂ entering its cells from the internal atmosphere. Through the main tissue, conducting tissues consisting of xylem and phloem pass. The xylem is formed of lignified and mostly dead cells. Its main part is either solid tubes formed by the fusion of cells and called vessels or tracheae (the latter name was given earlier when it was thought that they were normally filled with air and served for respiration), or closed elongated cells located one after another (so-called tracheids). The phloem consists of living cells with cellulose walls. Its main significance is in the sieve tubes formed by cells arranged in a row with finely perforated transverse walls between them. The xylem serves mainly for the movement of water and dissolved mineral salts going from the root upward (ascending current), while the phloem serves for conducting the solution of organic substances produced in the leaves and moving downward to the root (descending current). To the conducting tissues, mechanical tissues of lignified thick-walled cells are mostly also attached. The combination of these forms the so-called vascular-fiber bundles, noticeable for example in the form of leaf veins. In many cases, in the vascular-fiber bundles of the stem and root, a layer of embryonic tissue called the cambium remains between the phloem and xylem. Thanks to it, the bundle can thicken by the formation of new elements of phloem and xylem. In perennial stems and roots, this thickening often leads to the fusion of individual bundles and the deposition inside the cambium of solid masses of xylem (secondary wood), and outside - similar masses of phloem (secondary bark). Intercellular spaces of the main, as well as other tissues, sometimes expand into larger cavities and channels (schizogenous channels and cavities) or they are formed as a result of local destructions and dissolutions of cells (lysigenous channels and cavities). Both of these mostly serve as receptacles for excreta in the form of resins, balsams, etc., secreted by the surrounding cells. These cavities normally do not communicate with the outside world and in their significance and origin have no similarity with the body cavities of animals. Most higher plants are perennial. In this case, in trees and shrubs, preservation from year to year occurs in such a way that the entire aerial stem is preserved (leaves mostly die off annually), while in perennial herbs only the lower aerial part of the stem (and roots) is preserved. This overwintering part of the stem is mostly developed in the form of a rhizome, similar to the root in its position underground and absence of chlorophyll, but differing in that it bears leaves in the form of scales and buds at the end. From them the following spring a new aerial stem with green leaves develops. Often such rhizomes are thickened due to the accumulation of reserve nutrients in them. The stem origin and significance are similar to tubers (tuber) and bulbs (bulba), differing from the rhizome by more rounded outlines, and bulbs also by a more strongly developed scale-like leaves. Rhizomes, tubers and bulbs serve not only for the wintering of plants but also determine their asexual and vegetative reproduction, since several of them can form and all of them the following spring can develop into a new plant. A more specialized sexual reproduction in most higher plants is associated with the formation of seeds, which are formed either openly on the surface of mostly flat scales, usually collected in cones (in gymnosperms, such as pine and spruce), or in most cases inside special fruits (in angiosperms). The seed is clothed in a shell, and its inner part consists either only of the embryo or also of a special nutrient tissue - endosperm. At maturity in most plants, seeds lose water and pass into a state of anabiosis, withstanding at the same time the effect of strong cooling and other unfavorable conditions. Through them, both annual and perennial plants can survive in natural conditions during an unfavorable period. For seed germination, water and a suitable temperature (within the range from 1° to 35-40° with an optimum for most around 25°) are necessary. Under these conditions, the protoplasmic colloids of the embryo's cells swell, and the life processes suspended during drying resume: the consumption of reserve substances begins, vigorous respiration and growth of the embryo, which breaks through the seed shell and gradually grows into a new plant. Higher plants are divided into the following classes: 1) mosses (see), 2) ferns, 3) gymnosperms, 4) angiosperms. Ferns now number approximately 6,000 species, but they predominated in the vegetation of the Paleozoic and Mesozoic eras. They are represented mostly by large perennial herbs, rarely (in the tropics) trees. These include: 1) true ferns, characterized mostly by large divided leaves (fronds), emerging in a bunch directly from the underground rhizome, 2) horsetails - with a developed aerial stem and reduced scale-like leaves, 3) clubmosses - with long creeping stems and small leaves. The reproduction of ferns occurs as follows: spores develop on their leaves.

Growing on the ground, they develop a prothallus mostly in the form of a green plate up to 1 cm in diameter. On it are formed the sexual organs: female archegonia in the form of bottles, each with one egg, and male antheridia in the form of sacs with numerous spermatozoa. The fertilized egg develops into a new fern that produces spores. Thus, in the development cycle, the asexual, or spore generation (sporophyte) in the form of the fern itself alternates with the sexual (gametophyte) in the form of the prothallus. Ferns currently have little importance. Official: Aspidium filix mas (rhizome - Rhizoma filicis maris), Adiantum capillus Veneris (leaves - Folia Adianti, s. Herba Capilli veneris), Lycopodium clavatum (spores - Semen Lycopodii). Some species of horsetail (Equisetum) are poisonous. - A tincture of the spring shoots of Equisetum arvense is used in folk medicine. Gymnosperms currently number about 550 species, but were more abundant in the Paleozoic and Mesozoic eras. Mostly trees, often found in masses (coniferous forests). In reproduction, male cones develop that produce male spores, or pollen, and female cones that develop on their scales so-called ovules. Pollen is carried by the wind to female cones and fertilizes the ovules, each of which grows into a seed. Gymnosperms are important as the most important forest trees (pine, spruce, fir, larch, etc.). Official: Juniperus communis (Fructus Juniperi, Oleum Juniperi), Juniperus sabina (Herba Sabinae), Larix europaea (Terebinthina veneta), Larix sibirica (Pix liquida), various species of pine - Pinus, spruce - Picea and fir - Abies (Terebinthina, Colophonium, Oleum Terebinthinae, Pix liquida). Poisonous: Juniperus sabina - Cossack juniper and Taxus baccata - yew. In folk medicine, Ephedra vulgaris - ephedra is used. Angiosperms now predominate over all other plants and number more than 150,000 species of herbs, shrubs and trees. All are characterized by the fact that seeds are formed in fruits, which originate from the flower (angiosperms are also called flowering plants). The flower usually consists of a perianth of mostly brightly colored, close-set leaflets, stamens, and a pistil (or pistils). The stamens represent organs that produce pollen, and the pistils in their lower expanded part, called the ovary, have a cavity containing ovules. After pollination, the pollen grain develops a fertilization tube, which reaches the ovule and, by pouring its contents into it, fertilizes it. Then the ovary grows, turning into a fruit, and the ovules develop into seeds. Botanically, fruits are classified by the number of seeds they contain and by the nature of the pericarp (or epicarp), i.e., the part surrounding the seeds, which originates from the walls of the ovary. Thus, the following types of fruits are distinguished: 1) capsule (capsula) - a multi-seeded fruit with a dry, opening pericarp when ripe, e.g., poppy, also legume (legumen) of legumes (see); 2) berry (baccia) - a fruit with a succulent pericarp and mostly multi-seeded, e.g., grape, currant, also apple; 3) drupe (drupa) - a fruit with a succulent pericarp in the outer parts and hard woody in the inner parts, almost always single-seeded, for example cherry, as well as almond or walnut (in them the pulp dries up and falls off when ripe); 4) nut (nux) - a single-seeded fruit with a woody pericarp, e.g., hazel, sunflower. More specialized: schizocarpium in umbellifers and some others, dividing at maturity into single-seeded parts; grain of cereals - a dry single-seeded fruit with a pericarp adhering to the seed; composite fruit of raspberry and others, consisting of many succulent single-seeded fruitlets and others. 33 8^ The class of angiosperms is divided into two subclasses: monocotyledons and dicotyledons (or more briefly - monocots and dicots). The first have one primary leaf (cotyledon) in the seed embryo, while the second have two. In addition, monocots are mostly characterized by the following: 1) they do not have a cambium and their stems do not thicken; 2) the veins in the leaf run parallel, not forming a network; 3) the number of parts in the flower (petals, stamens, etc.) is 3 or a multiple of three (three-merous flower). Dicots are characterized by: 1) mostly the presence of a cambium in the stems (and roots), due to which perennial stems grow in thickness; 2) net-veined leaves; 3) mostly four-merous or five-merous flower structure. In turn, dicots are divided into apetalous and sympetalous, depending on how the perianth is arranged, from separate leaflets or from fused ones together. - The following main families belong to the monocots: 1) Araceae (see). 2) Palmae, exclusively tropical woody plants (the only woody group among monocots); they have important economic significance in tropical countries. These include: Cocos nucifera (coconut palm), Phoenix dactylifera (date palm), Elaeis guineensis (oil palm), Calamus (bent furniture), Phytephas (vegetable ivory, used for buttons, etc.) and others. Official: Areca catechu (Semen Arecae). 3) Liliaceae, mostly large perennial herbaceous plants, distributed in the tropics and in temperate climates. Many have bulbs. Flowers are mostly large, brightly colored. In the tropics there are several woody liliaceous plants: Dracaena, Aloe, Jucca, with a stem thickening in a special way. Official: Colchicum autumnale (Semen Colchici), Veratrum album (Rhizoma Veratri), several species of Aloe, Convallaria majalis (Herba Convallariae), species of Smilax (Radix Sarsaparillae). Many are poisonous; in our country especially: Colchicum, Veratrum, Paris. 4) Iridaceae, close to the liliaceous, but differ in the inferior ovary (the perianth and stamens arise from the upper part of the ovary, and not from below, as in the usual superior ovary of liliaceous plants and others). Official: Crocus sativus (saffron), Iris florentina (Rhizoma Iridis). 5) Orchidaceae, a very extensive (up to 10,000 species), predominantly tropical family. Perennial herbs, often epiphytes on tree branches in the tropics. Mostly characterized by brightly colored flowers of complex structure, very well adapted to cross-pollination with the help of insects; inferior ovary. Official: species of Orchis (Tubera Salep), Vanilla planifolia (Fructus Vanillae). Dicots apetalous. Main families: 6) Cupuliferae. Trees; flowers with a dull perianth, unisexual (only with stamens or only with a pistil), gathered (especially the staminate flowers) in catkin-like inflorescences. They mostly bloom in early spring before the leaves unfold and are pollinated by the wind. The fruits are covered at the base with a special cupule (cupula). Close to this family, but without a cupule on the fruits, are the birch (Betulaceae), willow (Salicaceae), and some others. All of them were formerly united into one family, the Amentaceae, by the characteristic gathering of flowers into catkins. These include the most common tree species: oak (Quercus), hazel (Corylus), beech (Fagus), chestnut (Castanea) - all from Cupuliferae; in addition birch (Betula), alder (Alnus), willow (Salix), poplar (Populus), walnut (Juglans) and others. Official: Quercus (Cortex Quercus et Semen Quercus), Fagus silvatica (Pix Liquida), species of Salix (Cortex Salicis), Juglans regia (Folia Juglandis). 7) Urticaceae and some families close to them (Ulmaceae, Moraceae, etc.). Herbs or trees with inconspicuous small flowers, gathered in dense inflorescences. Mostly pollinated by the wind. Fruits - nuts. Official: Ficus elastica (rubber), Cannabis sativa (Fructus Cannabis), Cannabis sativa var. indica (Herba Cannabis ind., hashish), Humulus lupulus (Glandulae, s. Strobili Lupuli). Many are poisonous: in the USSR, stinging nettle (Urtica dioica and U. urens, poison is contained in the stinging hairs); similar in the tropics, but more dangerous: Laportea; also belongs here the upas tree (Antiaris toxicaria). Useful and cultivated: mulberry (Morus alba), hemp (Cannabis sativa), hop (Humulus lupulus), fig tree (Ficus carica), ramie (Boehmeria nivea). 8) Ranunculaceae. Mostly herbs with large, bright flowers. Flowers are bisexual with numerous stamens and pistils. Fruits are mostly complex - of nuts. Official: Aconitum Napellus (Tubera Aconiti), Hydrastis canadensis (Rhizoma Hydrastis). Very many are poisonous. 9) Rosaceae. Trees, shrubs and mostly herbs with large, bright flowers of five-merous type, but often with numerous stamens. Flowers are bisexual. Fruits various, mostly succulent. Official: Pirus malus (Extractum ferri pomati)_r Cydonia vulgaris (Semen Cydoniae), Rosa centifolia (Flores Rosae, Oleum Rosae), Prunus amygdalus (Amygdalae dulces et A. amarae, Oleum Amygdalarum), Prunus laurocerasus (Aqua Laurocerasi) and others. Many cultivated fruit plants: apple (Pirus malus), pear (Pirus communis), quince (Cydonia vulgaris), mountain ash (Sorbus).

(Sorbus aucuparia), strawberry (Fragaria vesca; cultivated varieties often under the name of garden strawberry), raspberry (Rubus idaeus), plum (Prunus domestica), cherry (Prunus cerasus), sweet cherry (Prunus avium), apricot (Prunus armeniaca), peach (Prunus persica), almond (Prunus amygdalus) and others. 10) Legumes (Leguminosae)- see Legumes. 11) Crucifers (Cruciferae). Herbs; flowers of bright tetramerous type (but with 6 stamens). Fruit - a two-valved capsule (otherwise called a pod). Official: Brassica nigra (Semen Sinapis), Sinapis alba (Semen Erucae), Cochlearia officinalis (Herba Cochleariae). Many vegetable plants: cabbage (Brassica oleracea), rutabaga (Brassica napus rapifera), turnip (Brassica rapa), radish (Raphanus sativus) and others. 12) Euphorbiaceae. Herbs, mostly with milky juice, rarely (in the tropics) trees. Flowers unisexual and inconspicuous. Fruit - a three-lobed capsule, often splitting into 3 nuts. Official: Ricinus communis (Ol. Ricini), Croton eluteria (Oleum Crotonis); species of tropical trees Hevea yield rubber. 13) Umbellifers (Umbelliferae). Large herbs, mostly with hollow stems and dissected leaves. Flowers pentamerous with inferior ovary, collected in inflorescences in the form of an umbrella. Fruit - splitting into two nuts. Official: Archangelica officinalis (Radix Archangelicae), Levisticum officinale (Radix Levistici), Pimpinella saxifraga and P. magna (Radix Pimpinellae), Pimpinella anisum (Fructus Anisi, Ol. Anisi), Foeniculum vulgare (Fructus Foeniculi), Carum carvi (Fructus Carvi), Coriandrum sativum (Fructus Coriandri) and others. Poisonous: Conium maculatum, Cicuta virosa and others. Vegetables: carrot (Daucus carota), parsnip (Pastinaca sativa), celery (Apium graveolens), parsley (Petroselinum sativum), dill (Anethum graveolens) and others. 14) Loranthaceae. Parasites on stems and roots of woody plants, mostly tropical. In our southwest - mistletoe (Viscum album), official. Dicotyledonous sympetalous: 15) Labiates (Labiatae). Herbs with 4-angled stems and opposite leaves. Flowers bilabiate (2 petals form one lip and the other three). Fruit - splitting into 4 nuts. Official: Salvia officinalis (Folia Salviae), Lavandula vera (Flores Lavandulae et Ol. Lavandulae), Melissa officinalis (Folia Melissae), Mentha piperita (Folia Menthae piperitae et Ol. Menthae piperitae) and others. aromatic plants, of which there are very many in this "family. 16) Nightshades (Solanaceae). Herbs with regular pentamerous flowers. Fruits two-celled, many-seeded, dry or fleshy. Official: Atropa belladonna (Folia Belladonnae, Atropinum), Datura stramonium (Semen et Folia Stramonii), Hyoscyamus niger (Folia Hyoscyami). Cultivated: potato (Solanum tuberosum), tobacco (Nicotiana tabacum and N. rustica), podded pepper (Capsicum annuum), tomato (Solanum lycopersicum). 17) Figworts (Scrophulariaceae). Herbs with large more or less irregular pentamerous flowers. Fruit - a two-celled capsule. Official: Digitalis purpurea (Folia Digitalis), Verbascum thapsiforme and V. phlomoides (Folia Verbasci). 18) Bellflowers (Campanulaceae). Herbs with large regular pentamerous flowers with inferior ovary. Fruit - mostly a three-celled capsule. Close to this family are Lobeliaceae (Lobelia inflata-official) and Cucurbitaceae with mostly large fleshy fruits (cucumber - Cucumis sativus, watermelon-Citrullus vulgaris, pumpkin-Cucurbita pepo and Cucurbita maxima, melon-Cucumis melo). 19) Composites (Compositae). The most extensive of all families (about 12,000 species). Almost exclusively herbs. Flowers small pentamerous with inferior ovary. Fruit - a nut. Flowers collected in dense inflorescences (capitula), forming as a whole one large flower. Official: Artemisia absinthium (Herba Absinthii), Matricaria chamomilla (Flores Chamomillae, Ol. Chamomillae), Cnicus benedictus (Herba Cardui benedicti), Achillea millefolium (Herba Millefolii), Anthemis nobilis (Flores Chamomillae romanae), Taraxacum officinale (Radix Taraxaci); some species of Chrysanthemum from the Near East yield insect powder (Persian chamomile and others). Cultivated: chicory (Cichorium intybus), lettuce (Lactuca sativa), Jerusalem artichoke (Helianthus tuberosus), sunflower (Helianthus annuus), salsify (Scorzonera hispanica). Recently discovered in Kazakhstan and already cultivated here tausagyz (Scorzonera tausagyz) contains significant amounts of rubber. Also rubber-bearing are some other composites,

such as the Mexican guayule (Parthenium argentatum) and others.