A genus of annual perennial plants of the cereal family. Acquaintance with cereals. Description of cereals and their significance for humans

Among all families of flowering plants, cereals occupy a special position. It is determined not only by their high economic value, but also by the great role they play in the formation of herbaceous groups of vegetation - meadows, steppes, prairies and pampas, as well as savannas. Cereals include the main food plants of mankind - soft wheat (Triticum aestivum), sowing rice (Oryza sativa) and corn (Zea mays), as well as many other cereals that supply us with such essential products as flour and cereals. Perhaps no less important is the use of cereals as food plants for domestic animals. The economic value of cereals is diverse in many other respects.

There are 650 genera and: from 9,000 to 10,000 species of cereals. The range of this family covers the entire land area of ​​the globe, excluding areas covered with ice. Bluegrass (Roa), fescue (Festuca), pike (Deschampsia), foxtail (Alopecurus) and some other genera of cereals reach the northern (in the Arctic) and southern (in the Antarctic) limits of the existence of flowering plants. Among flowering plants that rise highest in the mountains, cereals also occupy one of the first places.

Cereals are characterized by the relative uniformity of their distribution on Earth. In tropical countries, this family is about as rich in species as in countries with a temperate climate, and in the Arctic, cereals rank first among other families in terms of the number of species. Among cereals, there are relatively few narrow endemics, but they are cited for Australia 632, for India - 143, for Madagascar - 106, for the Cape region - 102. In the USSR, Central Asia (about 80) and the Caucasus (about 60 species). Cereals are usually easy to recognize by their appearance. They usually have segmented stems with well-developed nodes and alternate two-row leaves, divided into a sheath covering the stem, a linear or lanceolate plate with parallel venation and a membranous outgrowth located at the base of the plate, called a tongue or ligula. The vast majority of cereals are herbaceous plants, but many representatives of the bamboo subfamily (Bambusoideae) have tall, highly branched in the upper part, with numerous nodes, the stems are strongly lignified, however, retaining the structure typical of cereals. In the South American species of bamboo (Bambusa), they are up to 30 m high and 20 cm in diameter. In the South Asian giant dendrocalamus (Dendrocalamus giganteus), the stem of 40 m is not inferior in growth to many trees. Among the bamboo, climbing or curly, sometimes thorny liana-like forms are also known (for example, the Asian dinochloa - Dinochloa). The life forms of herbaceous grasses are also quite diverse, although outwardly they look like the same. There are many annuals among cereals, but perennial species predominate, which can be turfy or have long creeping rhizomes.

Like most other monocots, cereals are characterized by a fibrous root system resulting from the underdevelopment of the main root and its very early replacement by adventitious roots. Already during seed germination, 1 - 7 such adventitious roots develop, forming the primary root system, but after a few days from the lower adjacent nodes of the seedling, secondary adventitious roots begin to develop, from which the root system of an adult plant is usually formed. In cereals with tall, erect stems (for example, in corn), adventitious roots can also develop from nodes above the soil surface, acting as supporting roots.

In most cereals, branching of shoots occurs only at their base, where the so-called tillering zone, consisting of closely spaced nodes, is located. In the axils of leaves extending from these nodes, buds are formed, giving rise to lateral shoots. In the direction of growth, the latter are divided into intravaginal (intravaginal) and extravaginal (extravaginal). During the formation of an intravaginal shoot (Fig. 192, 1), the axillary bud grows vertically upward inside the sheath of its cover sheet. With this method of shoots, very dense tussocks are formed, as in many species of feather grass (Stipa) or fescue fescue (Festuca valesiaca). The bud of the extravaginal shoot begins to grow horizontally and pierces with its tip the sheath of the covering leaf (Fig. 192, 2). This method of shoot formation is especially typical for species with long creeping underground shoots-rhizomes, for example, for creeping wheatgrass (Elytrigia repens). However, it is not uncommon for extravaginal shoots to quickly change the direction of their growth to vertical, as a result of which tussocks are formed, no less dense than with the intravaginal method of shoots. In many cereals, mixed shoots are also known, when each plant forms shoots of both types (Fig. 192).

Branching of stems in their middle and upper parts in cereals of extratropical countries is rare and usually only in species with stems creeping along the ground (for example, in the coastal woman - Aeluropus). It can be seen much more often in cereals of the tropics, and their lateral shoots usually end in inflorescences. The turf of such cereals often resembles bouquets or brooms in appearance. Especially strongly branched in the upper part of the stems are characteristic of large bamboo, and they even have a whorled arrangement of lateral branches, for example, in some Central American species of ceskeia - Chusquea (Fig. 193, 5). Many cereals with aerial shoots creeping and rooting at nodes, for example, the grass of the bison (Buchloё dactyloides) of the North American prairies (Fig. 194, 6), can form large clones that cover the soil with a thick carpet. In the North American torrey muhlenbergia (Muhlenbergia torreyi) and some other species, such clones grow along the periphery and die off in the middle, forming a kind of "witch's rings" in some species of fungi.

For perennial grasses of extratropical countries, the formation of often very numerous shortened vegetative shoots with nodes closely spaced at their base is very characteristic. Such shoots can exist for one or several years, and then move on to flowering. Elongated reproductive shoots are formed from them after the appearance of the rudiment of a common inflorescence due to the rapid interstitial growth of internodes. Moreover, each segment of the shoot of the cereal grows independently under the protection of the leaf sheath, having its own zone of the intercalary meristem. The core in growing internodes usually dies off quickly and they become hollow, but in many tropical cereals (for example, in corn), the core is not only preserved throughout the stem, but also has scattered conductive bundles. Core-filled internodes are also found in many liana-like bamboo. Sometimes, during the transition to an elongated reproductive shoot, only the uppermost internode located under the inflorescence is lengthened, for example, in the blue moth (Molinia coerulea).

As a rule, the stems of cereals have a cylindrical shape, however, there are also species with strongly flattened stems, for example, the flattened bluegrass (Poa compressa), which is widespread in the European part of the USSR. Some of the lower shortened internodes of the stem can thicken in a tuber-like manner, serving as a storage facility for nutrients or water. This feature is found in some ephemeroid cereals (for example, in bulbous barley - Hordeum bulbosum), but it is also found in mesophilic meadow species. In oak bluegrass (Poa sylvicola), the shortened internodes of creeping underground shoots become tuberous thickened.

The signs of the anatomical structure of the stem are used in the taxonomy of cereals. So, for most extratropical cereals, usually called festucoid (from Festuca - fescue), internodes of stems with a wide cavity and an arrangement of bundles of conductive tissue in 2 circles (outer of smaller bundles) are characteristic, and for predominantly tropical - panicoid (from Panicum - millet) - internodes with or without a narrow cavity and with the arrangement of conducting bundles in many circles.

The leaves of cereals are always arranged alternately and almost always two-row. Only the Australian genus Micraira has a spiral leaf arrangement. Leaves in the form of more or less leathery scales, homologous to leaf sheaths, are usually found on rhizomes, and often also at the base of aerial shoots. In many bamboo, falling scaly leaves without plates or with very small plates are often located almost along the entire length of the main shoot. The scales have a predominantly protective meaning and usually follow the very first leaf-shaped shoot organ - always a scale-like and usually two-keeled pre-leaf.

In ordinary, assimilating leaves, the sheath is formed by the base of the leaf that has grown in the form of a sheath covering the stem and serves as a protection for the growing internode. The sheaths of cereals can be split up to the base (for example, in the predominantly tropical tribes of millet-Paniceae and sorghum-Andropogoneae), and fused edges into a tube (in tribes of the campfires - Bromeae and pearl-grass - Meliceae). In some species of steppes and semi-deserts (for example, bulbous bluegrass - Poa bulbosa, Fig. 195, 4), the leaf sheaths of vegetative shoots become a storage organ, and the shoot as a whole resembles a bulb. In many cereals, the dead sheaths of the lower leaves protect the shoot bases from excessive evaporation or overheating. When the conducting bundles of the sheaths are connected with each other by strong anastomoses, a net-fibrous cap is formed at the base of the shoots, characteristic, for example, of the coastal rump (Bromopsis riparia) common in the steppes of the European part of the USSR.

Located at the base of the leaf blade and directed vertically upward, the membranous or thin-skinned outgrowth - the tongue, or ligula, apparently prevents the penetration of water, and with it bacteria and fungal spores, into the vagina. It is no coincidence that it is well developed in mesophilic and hydrophilic grasses, and in many xerophilic groups, especially in the subfamily of field grass (Eragrostoideae), it is modified into a series of densely spaced hairs. In most species of the widespread genus Echinochloa and in the North American genus Neostapfia, the tongue is completely absent and the vagina passes into a plate without a clearly defined border between them. On the contrary, the Mexican caudate Muhlenbergia (Muhlenbergia macroura) has very long (2-4 cm) tongues. At the apex of the vagina on the sides: from the uvula, some cereals (especially bamboo) have 2 lanceolate, often crescent-shaped outgrowths called ears.

In the vast majority of cereals, the leaf blades have a parallel venation, linear or linear-lanceolate, and are connected to the sheath by a wide or only slightly narrowed base. However, in the genus Arthraxon and in a number of other, mainly tropical, genera they are lanceolate-ovate, and in 2 African genera - Phyllorachis and Umbertochloa - even arrow-shaped at the base (Fig. 196, 10) ... In the subfamily of bamboo, leaf blades are usually lanceolate and narrowed at the base into a more or less developed petiole. In the Brazilian herbaceous bamboo anomochloa (Anomochloa), the leaf blades are cordate and connected to the sheaths by a petiole, up to 25 cm long (Fig. 197, 7). Leaves of another American genus, Pharus (Pharus), also have very long petioles, which have one more feature that is not characteristic of other cereals - the pinnate venation of the plates. In most bamboo, as in some broadleaf grasses from other subfamilies, the leaf blades have well-developed transverse anastomoses between parallel main veins. The overall dimensions of the leaf blades also vary greatly. In the North American littoral species, Monanthochloe littoralis, the plates of densely spaced leaves rarely exceed 1 cm in length, while in the South American bamboo neurolepis tall (Neurolepis elata) they are up to 5 m long and 0.6 m wide.Very narrow, bristle-like folded along or folded leaf blades have many types of feather grass, fescue: and other, usually xerophilous cereals. In the African bristle-leaved miscantidium (Miscanthidium teretifolium), very narrow plates are represented by almost only one midrib.

The anatomical structure of leaf blades, as a systematic feature, is of even greater value in cereals than the anatomical structure of stems, and is usually characteristic of subfamilies and tribes. Currently, there are 6 main types of the anatomical structure of leaf blades: festucoid, bamboo (from Bambusa - bamboo), arundinoid (from Arundo - arundo), panicoid, aristidoid (from Aristida - tricuspid) and chloride or eragrostoid (from Chloristoid) - chloris and Eragrostis - field vole). The festucoid type (mainly extratropical tribes of cereals) is characterized by a disordered arrangement of chlorenchyma, a well-developed internal (sclerenchymal) and relatively weakly delimited from chlorenchymal external (parenchymal) sheaths of vascular bundles (Fig. 198, 1). The bamboo type, characteristic of the bamboo subfamily, is in many ways similar to the festucoid, but differs in chlorenchyma, which consists of peculiar lobed cells arranged in rows parallel to the epidermis, as well as the outer sheath of conductive bundles, which is more isolated from chlorenchyma (Fig. 198, 2). In the arundinoid type, characteristic of the subfamily of reeds (Arundinoideae), the inner lining of the bundles is poorly developed, and the outer sheath is well developed and consists of large cells without chloroplasts, the cells of chlorenchyma are densely and partly radially around the bundles. For the rest of the types (mainly tropical subfamilies of field grass and millet), the radial (or crown) arrangement of chlorenchyma around the vascular bundles is characteristic, moreover, in the chloride type, the inner (sclerenchymal) sheath of the bundles is well developed, and in the panicoid and aristidoid types, it is absent or poorly developed (Fig. 198, 5).

It turned out that many other physiological and biochemical features are associated with the radial (crown) arrangement of chlorenchyma and the well-separated outer (parenchymal) sheath of vascular bundles (the so-called kranz syndrome, from German kranz - wreath), primarily a special method of photosynthesis - C4 way of fixing carbon dioxide, or cooperative photosynthesis, based on the cooperation of chlorenchymal cells and parenchymal sheaths that perform different functions. Compared to conventional C3 by fixing carbon dioxide, this route is very economical in terms of moisture consumption and therefore is beneficial when living in arid conditions. The advantages of kranz syndrome can be seen on the example of the species of the field vole (Eragrostis), bristles (Setaria) and the lurker (Crypsis) in the southern regions of the USSR: the maximum development of these species falls on the driest season here - July - August, when the majority cereals ends the growing season.

According to the structure of the epidermis of the leaves, especially the silicified cells and hairs, the above types of the anatomical structure of the leaves are also well distinguished. The stomata of cereals are very peculiar. They are paracytic, with guard cells of a special, so-called graminoid type. In the middle part, these cells are narrow with strongly thickened walls, and at the ends, on the contrary, they are widened with thin walls. This structure allows you to regulate the width of the stomatal gap by expanding or narrowing the thin-walled parts of the guard cells.

Flowers of cereals are adapted to wind pollination and have a reduced perianth, stamens with long flexible filaments and anthers hanging from them, long feathery stigmas and completely dry pollen grains with a smooth surface. They are collected in elementary inflorescences, very characteristic of cereals, - spikelets, which, in turn, form common inflorescences of various types - panicles, brushes, ears or heads. A typical multi-flowered spikelet (Fig. 199, 1) consists of an axis and two rows of scales alternately located on it. The two lowest scales, which do not carry flowers in their axils, are called spikelets - the lower and upper (usually larger), and the higher scales with flowers and their axils are called the lower floral scales. Both are homologous to leaf sheaths, and the lower floral scales often bear awn-shaped appendages, which are usually considered homologous to leaf blades. Some bamboo have more than two spikelet scales, and in the leaf grate (Phyllostachys) such scales often bear small leaf blades (Fig. 200, 7). On the contrary, in some herbaceous grasses, one (in the chaff - Lolium) or both (in the sheath - Coleanthus, Fig. 201, 6) spikelet scales can be completely reduced. True spikelet scales are in origin upper leaves, and not bracts (bracts), like the lower flower scales. However, in many cases (especially in the millet tribe), the reduction of flowers in the axils of the lowest floral scales makes the latter very similar to additional spikelet scales. The spikelet and lower floral scales of the most primitive bamboo have, like leaf sheaths, a large and variable number of veins, which in the course of the evolution of the family decreased to 5, 3, or even 1 vein.

The number of flowers in spikelets can vary from very large and indefinite (for example, in a two-spike - Trachynia - up to 30 flowers, Fig. 201, 14, 15) to constantly one (in a reed grass or foxtail) or two (in calamus - Aira ). Chinese bamboo (Pleioblastus dolichanthus) has very primitive multiflorous spikelets with a strongly elongated and often branched axis. Such spikelets are more similar not to spikelets, but to branches of a paniculate common inflorescence (Fig. 200, 1). Spikelets are even less distinguishable in common inflorescences of tropical bamboo Melocanna. In it, in the axils of the spaced lower floral scales, not 1, but 2 or 3 flowers are placed on the lateral axes equipped with bracts. It is likely that the evolution of common inflorescences in cereals proceeded from such common inflorescences not yet differentiated into spikelets to inflorescences with well-separated, first multi-flowered, and then single-flowered spikelets.

The axis of a multi-flowered spikelet usually has articulations under each of the lower floral scales and splits into segments during fruit. The base of the lower floral scales, growing together with such a segment, forms a thickened callus, which can be long and sharp, like a feather grass. The part of the spikelet, including one flower, flowering scales and the adjacent segment of the spikelet axis is often called antetium. In single-flowered spikelets, there may be no articulation under the lower floral scales, and then the spikelets fall off with the fruits entirely.

Common inflorescences of cereals usually have the form of a panicle, often very dense and spike-like, brush or spike. Only small specimens of two spikelets (Fig. 201, 14), species of fire (Bromus) and some other cereals bear only one large spikelet at the top of the stem. There are also very dense, head-shaped common inflorescences, for example, in the African bamboo oxytenanthera Abyssinian (Okutenanthera abyssinica, Fig. 193, 1) or in the Mediterranean ephemera of the barbarian grass (Echinaria, Fig. 201, 11), and sandpits (Ammochloa, Fig. 201, 7 ). In the spiny bristle (Cenchrus), the common inflorescence consists of several spiny heads (Fig. 202, 8, 9). The result of a higher specialization of common inflorescences is an ordered arrangement of spikelets one by one or in groups of 2-3 on one side of the flattened axes of spike-shaped branches, which, in turn, can be arranged alternately or finger-like (like in a pig - Cynodon, Fig. 194 , 4). With this arrangement of spikelets, which is especially typical for tribes of millet, sorghum, and pork, some of the spikelets on spike-shaped twigs (usually located on the legs next to sessile bisexual spikelets) can be male or generally have only a rudiment of a flower. In Arraxon from the tribe of Sorghum, only a pedicle with a barely noticeable rudiment of a spikelet remains on the peduncle of the spikelet. Unisexual spikelets are not so rare in cereals. In this case, spikelets with male and spikelets with female flowers can be located within the same inflorescence (in Zizania, Fig. 196, 7, 9), on different inflorescences of the same plant (in corn) or on different plants (in the Pampas grass, or Cortaderia Sello - Cortaderia selloana, tab. 45, 3, 4).

In the axils of the lower floral scales, on the side of the spikelet axis, there is another scale, usually with 2 keels and a more or less noticeable notch at the apex. Since it does not belong to the axis of the spikelet, but to the axis of the flower and, therefore, is located above the base of the lower floral scales, it is called the upper floral scales. Previously, L. Chelakovsky (1889, 1894) and other authors took it for 2 accrete segments of the outer circle of the perianth, but now most authors consider it to be the pre-leaf of a strongly shortened shoot, which bears a flower, located in the sinus of the lower floral scales. In some genera of grasses (for example, the foxtail), the upper flowering scales can be completely reduced, while in the very original American herbaceous bamboo streptochaeta (Streptochaeta) it is almost split to the base.

Above the upper flowering scales, on the flower axis of a significant majority of cereals, there are 2 small colorless scales called flowering films or lodicules. There is still no consensus regarding their nature. Some authors take them for the rudiments of one of the two three-membered perianth circles, others for the rudiments of the bracts. The presence of a third, dorsal lodicula in many bamboos, as well as in genera of the feather grass tribe, seems to confirm the first of these points of view, although the dorsal lodicula usually differs in structure from the two ventral ones, usually closely adjacent and often connected to each other at the base.

The structure of the lodicules is considered an important systematic feature characteristic of whole tribes of cereals (Fig. 203). Large scale-like lodicules with conducting bundles are found in many bamboo, where they have a predominantly protective function. In most other grasses, the lodicula have the form of small whole or bilobed scales, devoid of or almost devoid of conducting bundles and strongly thickened in the lower half. It is assumed that such lodicules accumulate nutrients for the development of the ovary, regulate the water regime of the flower, and promote the spreading of the flower scales during flowering. Usually, there are 4 main types of lodicule structure: bamboo, festucoid, panicoid and chloride, corresponding to the main types of leaf anatomy. Often, there is also a melikoid type (from Melica - pearl barley), characteristic of the tribe of pearl barley (Meliceae): very short (as if chopped off in the upper part) lodicules stick together with their front edges. The above-mentioned streptochaete has 3 large, spirally arranged lodicules; however, not all authors take them for lodicules. Finally, in many genera (including foxtail and sheath), the lodicules are completely reduced.

The most primitive number of stamens - 6 - is found among cereals only in many bamboo and rice (Oryzoideae). The vast majority of cereals have 3 stamens, and in some genera their number decreases to 2 (in a fragrant spikelet - Anthoxanthum) or to 1 (in Zinnia - Cinna). The number and structure of stamens in the bamboo subfamily varies greatly. So, in the South Asian genus Ochlandra, the filaments of the stamens branch many times, as a result of which there can be up to 50-120 stamens in one flower. In the genera Gigantochloa and Oxytenanthera, the filaments of 6 stamens grow together into a rather long tube surrounding the ovary (Fig. 193, 3). The Brazilian anomochloi has 4 stamens. The filaments of the stamens of cereals are capable of rapidly lengthening during flowering. So, in rice, they lengthen by 2.5 mm per minute. Pollen grains of cereals are always single-pore with a smooth and dry shell, which is an adaptation to wind pollination.

There is still no consensus on the structure of the gynoecium in the flower of cereals. According to a more widespread point of view, the gynoecium of cereals is formed by 3 carpels that have grown together at their edges, and the fruit of cereals, the caryopsis, is a type of paracarpous fruit. According to another point of view, the gynoecium of cereals is formed by one carpel, which is a consequence of the reduction of two other carpels of the primary 3-membered apocarpous gynoecium. The ovary is always unilocular with one ovule, which can be from orthotropic to hemitropic (rarely campylotropic) with a micropyle directed downward. The integument is usually double, but in the otherwise abnormal genus Melokann, it is simple. Usually the ovary passes at the apex into 2 pinnate stigma branches, but many bamboo may have 3 of them. The bare bases of stigma branches differ greatly in length in different tribes. They are especially long in the predominantly tropical tribe of millet, which, apparently, is associated with more closely closed flowering scales. In some cereals, stigma branches can be fused with each other along the entire or almost the entire length. So, in corn, only the upper parts of the very long stigma branches are free, while in the whitebear (Nardus) the ovary passes at the apex into a completely whole filiform stigma, covered not with hairs, as in other cereals, but with short papillae. In bamboo - streptogyna (Streptogyna), stigma branches covered with spines become very tough after flowering and serve for the propagation of caryopses (Fig. 204, 4).

The non-opening, dry, single-seeded cereal fruit, called the caryopsis, has a thin pericarp, usually so tightly attached to the seed coat that it seems to have grown together with it. Often, when a caryopsis ripens, its pericarp also sticks together with flowering scales tightly attached to it. In sporobolus (Sporobolus), the pericarp remains disconnected from the seed and the caryopses in this case are called sac-shaped. The shape of the caryopses varies from almost spherical (in millet) to narrow-cylindrical (in many feather grass). On the convex, flat or concave in the form of a longitudinal groove, the ventral (ventral) side of the caryopsis has a scar, or gilum, usually darker than the rest of the caryopsis, and has a shape from almost round (in bluegrass) to linear and almost equal in the length of the entire caryopsis (in wheat). The scar is the place of attachment of the ovule to the ovule (funicular), and its shape is determined by the orientation of the ovule.

The most original in their structure are kernels of some bamboo, which can be berry-like with a thick fleshy pericarp or nut-like with a rather thick and very hard pericarp in consistency, separated from the seed coat. In the Melokanna, which is widespread in Southeast Asia, berry-like caryopses are inversely pear-shaped and reach 3-6 cm in diameter (Fig. 193, 9, 10). They have one more feature that is absent in all other cereals: during the development of the embryo, the endosperm of the seed is completely absorbed by the embryo and in the mature caryopsis only a dry film remains between the pericarp and the strongly overgrown scutellum.

In all other cereals, the endosperm makes up the majority of the mature caryopsis, and the ratio in the size of the endosperm and the embryo is of significant systematic importance. So, for festucoid grasses, relatively small sizes of the embryo are characteristic, and for panicoid cereals, they are larger in comparison with the endosperm. Usually, the endosperm of mature caryopses is hard in consistency, but it can be looser - mealy when it contains few proteins, or denser - glassy with a relatively high protein content. It can be noted that the endosperm of cereal grains contains prolamins proteins that are very characteristic of them and are not found in other plants. In the caryopses of some cereals (especially from the oat tribe), the endosperm is especially rich in oils and retains a semi-liquid (jelly-like) consistency during their full maturity. This endosperm is distinguished by its extraordinary resistance to drying, retaining a semi-liquid consistency even in caryopses that have been stored in herbaria for over 50 years.

The starch grains of the endosperm have a different structure in different groups of cereals. So, in wheat and other representatives of the wheat tribe, they are simple, very variable in size and without noticeable edges on their surface (triticoid type, from the Latin Triticum - wheat); in millet and other panicoid cereals, they are also simple, but vary less in size and have a verged surface, and in fescue and many other festucoid cereals, starch grains are complex, consisting of smaller granules (Fig. 205).

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The embryo of cereals (Fig. 206) is quite different in its structure from the embryos of other monocots. On the side adjacent to the endosperm, it has a thyroid body - a scutellum. Outside of it and closer to its upper part, there is an embryonic kidney, dressed with a two-keeled sheath-like sheet - a coleoptile. Many cereals have a small fold-like outgrowth called epiblast against the scutellum on the outside of the kidney. In the lower part of the embryo there is an embryonic root, dressed with a root sheath, or coleoriza. The nature of all these parts of the embryo is a matter of debate. The scutellum is usually taken for a single, modified cotyledon, and the coleoptile for its outgrowth or for the first leaf of the bud. The epiblast, when present, is taken either for a fold-like outgrowth of coleoriza, or for a rudiment of the second cotyledon. Coleoriza, according to some authors, is the lower part of the hypocotyl knee - the hypocotyl, in which the embryonic root is laid, according to others - a modified main root of the embryo.

The structural features of the embryo of cereals are of great systematic importance. Based on the presence or absence of epiblast or a gap between the lower part of the scutellum and coleoriza, as well as differences in the course of the conducting bundles of the embryo and in the shape of the first leaf of the embryo, 3 main types of embryo structure were established on the cross section: festucoid, panicoid, and eragrostoid, intermediate between them (Fig. . 206, 3). Thus, here, too, significant anatomical and morphological differences were revealed between predominantly extratropical, festucoid grasses and predominantly tropical, panicoid and chlorideoid grasses.

The anatomical and morphological features of cereals determine the very high plasticity and adaptability of representatives of this family to a wide variety of ecological conditions, which allowed them to spread throughout the land of the globe, up to the very extreme limits of the existence of flowering plants. Cereals are found in almost all plant groups, although they are most typical for meadows, steppes and savannas of various types. There are species that live on mobile sands (Selin - Stipagrostis, sandworm - Ammophila, etc.) and salt marshes (especially the coastal - Aeluropus and the rattle - Puccinellia), both coastal and inland. Some species of ratchet grow in a zone flooded by tides, and one arctic species, confined to such habitats, - the ratchet creeping (P. phryganodes) - often does not bloom, multiplying with the help of vegetative shoots creeping and rooting at the nodes. For the plain and upland meadows of Eurasia, numerous species of the genera bluegrass, fescue, bent grass (Agrostis), reed grass (Calamagrostis), foxtail, rump (Bromopsis), timothy grass (Phleum), waggon (Briza), etc. are especially characteristic. In the steppes of Eurasia, feather grass, fescue fescue, thin-legged fescue (Koeleria), wheatgrass (Agropyron), sheep (Helictotrichon), and in more southern regions - bearded vulture (Bothriochloa) are of leading importance. On the prairies of North America, chlorideoid grasses come to the fore: Bouteloua, Chloris, bison grass (Buchloe dactyloides), etc. ). In the pampas of South America, pampas grass species play an important role. - cortaderia (Cortaderia), forming giant turf (table. 45, 3, 4).

In forests, the role of grasses in the vegetation cover is naturally less significant; however, here, too, some species of this family can dominate in the herbaceous layer. So, in the spruce forests of Eurasia, reed grass (Calamagrostis arundinacea) often grows in abundance, and in oak forests - forest bluegrass (Roa nemoralis), dog elimus (Elymus caninus), giant fescue (Festuca gigantea) In contrast to steppe grasses, usually dense sod and having very narrow folded leaf blades along the length, forest grasses have less dense tussocks, wider and less rigid leaf blades. Of the two common barley species in deciduous and mixed forests of Eurasia, the more northern - wilted barley (Melica nutans) belongs to loose bunch grasses, and the more southern and therefore more xerophilic colored barley (M. picta) - to dense bunch. Among tropical and subtropical forest grasses, many have recumbent or climbing leafy shoots and very wide, lanceolate or lanceolate-ovate leaf blades, resembling in appearance the Tradescantia species widespread in greenhouse and indoor culture. For example, representatives of the genus Oplismenus have such a life form, one of the species of which, O. undulatifolius, is found in the moist forests of the Mediterranean, as well as in the Colchis lowland (Fig. 202, 1) ,. and the other, O. compositus, is very common in the forests of South Asia.

As for the grasses of the bamboo subfamily, their role in the vegetation of the humid tropics and subtropics is quite large. Treelike bamboo usually form large thickets along the banks of water bodies, along streams descending from the mountains, on the edges and clearings of tropical forests. Many herbaceous bamboo plants grow under the canopy of the tropical rainforest and tolerate significant shade. Aerial shoots of treelike bamboo are often considered homologous to the rhizomes of other cereals. They are distinguished by extremely fast growth and bear scaly leaves along their entire length - cataphylls, characteristic of the rhizomes of other cereals. All tree-like bamboos are evergreens, although their leaves gradually fall off as a result of the formation of separating tissue either at the base of the petioles, or at the base of the sheaths, which in this case fall off along with the plates.

Among bamboo with more or less woody stems, two main life forms are distinguished, confined to different climatic conditions (Fig. 207). Most tropical bamboos, whose development in natural conditions is controlled by the level of humidity (usually the onset of the rainy season), the stems are relatively close together, forming a kind of loose bush. Such bamboo have so-called pachimorphic (from the Greek “pachis” - thick) rhizomes: short and thick, sympodial, with asymmetric internodes filled with a core, the width of which is greater than the length. Another group of bamboo is common in areas with relatively cool or even cold winters, where the start of active growth of their shoots is controlled by temperature conditions. The genera belonging to it have leptomorphic (from the Greek "leptos" - thin) rhizomes: long and thin, monopodial, with hollow internodes, the length of which is much greater than their width. Such bamboo plants usually have relatively small overall sizes, although some species of leaf grate are up to 10 and even 15 m high.Leptomorphic rhizomes are also found in the only wild-growing genus of bamboo in the USSR - saza (Sasa), which forms very dense and difficult-to-pass thickets along the mountain slopes in the south. Sakhalin and the Kuril Islands.

Herbaceous bamboo, like cereals of other subfamilies, bloom annually, but bamboo with ligneous stems, as a rule, bloom once every 30-120 years and after that they usually die, being obligate or optional monocarps. In 1969, almost all over Japan, there was a massive and simultaneous flowering of a very widely cultivated there for technical purposes bamboo leaf grate (Phyllostachys bambusoides). This was a real disaster for those who grew it, since a significant part of the plantations died after flowering. Almost all Japanese grasses came from the same clone brought to Japan from China, and therefore it is not surprising that it bloomed everywhere at the same time.

Among perennial herbaceous grasses, especially tropical ones, there are giant forms that are not inferior in height to many bamboo ones. Such are, for example, common reed (Phragmites australis) and reed arundo (Arundo donax), which have multinodular, but unbranched stems up to 3, sometimes up to 5 m high and long, highly branched rhizomes (Fig. 208, 3).

Reeds are among the moisture-loving plants that form large and almost clean thickets along the banks of reservoirs, and often in water. The common reed is almost cosmopolitan and is widespread on all continents, both in the tropics and in temperate countries. This species has a fairly wide ecological range. It can also grow on swamps of various types, in swampy forests, on mountain slopes with groundwater inflow and on salt marshes, forming in extreme conditions of existence a peculiar form with only vegetative shoots creeping along the ground. However, even in normally developed flowering reed clones, caryopses are not always formed and in small numbers, which, apparently, is associated with the great antiquity of this species. Another giant, up to 3 m high, cereal - the Pampas grass, or cortaderia, one of the species of which has been introduced to the Mediterranean countries, forms very dense turf with intravaginal shoots (Table 45, 3, 4). Its narrow and very rigid leaf blades along the edges and midrib bear large thorns, resembling in this respect the leaves of the aquatic plant telores (Stratiotes).

The formation of dense turf is especially beneficial in arid climates, since in this case the base of the plant is well protected from the overheating topsoil. That is why among the steppe and desert grasses there are so many dense sod grasses (for example, the brilliant one, many species of feather grass, etc.). On the contrary, many meadow grasses belong to long-rhizome, especially those living on loose, weakly turfed soils, for example, creeping wheatgrass and awnless rump (Bromopsis inermis), which often grow in abundance on meadows of river-bed floodplains, as well as some coastal species that form dense thickets like reeds for example, species of manna (Glyceria), reed (Scolochloa), broad-leaved zizania, (Zizania latifolia), etc. Among the species of the generally hydrophilic tribe of rice (Oryzeae) there are also true aquatic plants. Such is, for example, the South Asian spinous hygroriza (Hygroryza aristata) with short and wide leaves, collected in rosettes, floating on the surface of the water due to strongly swollen sheaths.

A large and in many respects very interesting group of life forms is formed by annual cereals, which can be both spring, when seed germination begins in spring, and winter, when seeds begin to germinate in autumn and young plants winter, continuing their development in spring. Such a widely cultivated grain plant as wheat has not only many spring and winter varieties, but also “two-handed” varieties, which can be spring or winter depending on the sowing time. Annual cereals can be divided into 2 groups also according to their origin. One of these groups is the spring ephemera. Quickly completing their life cycle during spring - early summer, they play a very significant role in the composition of ephemeral vegetation in arid and subarid regions of Eurasia, Africa and North America. It is very important that such valuable food and forage crops as wheat, rye, oats and barley originate from the ancient Mediterranean ephemera.

Another large group of annual cereals belongs to the predominantly tropical tribes of millet, sorghum, porcine, triacle, etc., although some species of this group (for example, species of bristle grass, field grass, crabgrass - Digitaria, and barnyard grass) penetrate far beyond the tropics. All these cereals are relatively thermophilic and late developing. They usually bloom in the second half of summer - early autumn, being well adapted to endure the dry season. Among late annuals there are also many economically valuable species (sorghum, millet, chumiza, etc.), but there are also many malicious weeds of fields and plantations of various crops.

Among the annual cereals, species that are very original in appearance are known. Thus, in a bicolor spikelet (Trachynia distachya), the total inflorescence consists of only 1-2 large multi-flowered spikelets (Fig. 201, 14); in Echinaria capitata, the spikelets are collected in an almost spherical, prickly apical head at fruits (Fig. 201, 11); in the eastern root-head (Rhizocephalus orientalis) and the Palestinian sandbox (Ammochloa palaestina), spikelets collected in a dense head are located in the center of leaf rosettes (Fig. 201, 1-7). In the latter species, known in the USSR only from the sands of the Absheron Peninsula, almost the entire plant is often covered with sand, from which only the tops of the rosette leaves are visible. Biologically very interesting is the late ephemeral sheath flower (Coleanthus subtilis), which lives on the coastal shoals of more or less large rivers. It develops very quickly after leaving the shallows, reaching full development in September - early October. This is a small plant, 3-5 cm high, with recumbent or ascending shoots and very small, single-flowered spikelets without spikelet scales, collected in umbrella-shaped bunches (Fig. 201, 5). In years when the shallows remain flooded with water, this species does not develop at all and can generally disappear for many years. It is widespread in extratropical countries of the northern hemisphere, but extremely sporadically. So, in the USSR it was found only along the upper reaches of the Volkhov, the middle reaches of the Ob and along the Amur.

It has already been noted above that cereal flowers are highly specialized for wind-driven pollination. However, the accidental transfer of cereal pollen by insects, even in extratropical cereals, cannot be considered completely excluded. Recently, it has been established that herbaceous bamboo from the genera Olyra and Pariana, growing under the canopy of trees in tropical rain forests, where there is very little air movement, as a rule, are pollinated by insects, mainly flies and beetles, although such a secondary transition to entomophilia is not yet associated with any special adaptations.

The vast majority of perennial grasses are cross-pollinated, and self-pollination is usually hindered by complete or partial self-sterility. However, among annuals, there are a lot of facultatively self-pollinating species. Such are, for example, all types of wheat and aegilops (Aegilops), as well as most types of bonfires (Bromus). Some cereals, in addition to the usual spikelets with chasmogamous flowers, also develop spikelets with cleistogamous flowers, which are pollinated with closed scales. The formation of these spikelets guarantees the possibility of seed reproduction in adverse weather conditions or in case of excessive biting of the plant by herbivores. Thus, in the widespread coastal grass Leersia oryzoides and North American sporobolus cryptandrus, only spikelets with cleistogamous flowers are formed in unfavorable years and the panicles do not protrude from the enlarged sheath of the upper leaf. In the panicles of many feathergrass of the flora of the USSR, in dry years, only cleistogamous flowers are formed, and in cooler and wetter weather, all or almost all of the flowers of the panicle bloom openly. Many arctic cereals also bloom mainly cleistogamous in particularly cold weather.

In all species of the Eurasian genus serpentine (Cleistogenes) and some representatives of other genera, cleistogamous spikelets are constantly formed on short lateral branches hidden in the sheaths of the upper and middle stem leaves (Fig. 194, 2). The Central Asian northern nine-stalk (Enneapogon borealis) forms single spikelets with cleistogamous flowers inside special kidney-shaped shoots located at the base of the turf. Thanks to this feature, this species gets the opportunity to reproduce even under conditions of intensive grazing of pastures, when every year all the turf is almost to the base bitten by livestock. At the same time, the grazing cattle breaks the tussocks with their feet and carries along with the lumps of earth adhering to them, the weevil grains. An even higher specialization in this respect is noted in the North American amphikarpum (Amphicarpum). Its single spikelets with cleistogamous flowers are formed on the tops of creeping underground shoots under the soil surface (Fig. 202, 3).

Unisexual flowers are often found in cereals, but mainly in tropical species. These flowers can be located in one and the same spikelet together with bisexual flowers, for example, in a bison (Hierochloe) of 3 spikelet flowers, the upper one is bisexual, and the lower 2 are male, but more often they are in different spikelets. Such unisexual spikelets can, in turn, be located in the same inflorescence or in different inflorescences. As noted above, for many genera of the tribe sorghum, the arrangement of spikelets on spike-shaped branches of a common inflorescence in groups of 2 is very characteristic: one sessile with a bisexual flower, the other on a stem with a male flower. Bisexual, but with unisexual spikelets, the inflorescences of the South American herbaceous bamboo plant Piresia (Piresia) are located on creeping rhizome-like shoots, dressed with scaly leaves, and are often hidden under a litter of fallen leaves. Unfortunately, the method of pollination of flowers in species of this genus is still unknown. In the upper part of the panicle-shaped inflorescences of zizania, there are larger spikelets with female flowers, in the lower part - smaller ones with male flowers. In the genus Tripsacum, related to corn, spikelets with female, flowers are located in the lower part of the spike-shaped branches of the panicle, and with male ones - in their upper part (Fig. 209, 6). In corn, spikelets with male flowers form an apical panicle-shaped inflorescence, and spikelets with female flowers are collected in longitudinal rows on a strongly thickened axis of the ears, located in the axils of the middle stem leaves and enveloped in sheath-like leaves (Fig. 209, 1-3). Even more original is the arrangement of unisexual spikelets in the South Asian relative of corn, the coix. The lower, female part of the spike-shaped branches, located in the axils of the upper stem leaves, consists here of one spikelet with a female flower and the rudiments of two other spikelets, enclosed together in a kind of false fruit with a very dense, corneous or stony membrane. By origin, this fruit is a modified sheath of the apical leaf. From the upper part of it there are long stigma branches of a female flower and a leg of the male part of the branch, which is a rather thick false ear (Fig. 210, 7).

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Examples of dioecious cereals are the pampas grass (Cortaderia selloana, Tables 45, 3, 4) cultivated in gardens and parks in the south of the USSR and bison grass (Buchloe dactyloides) from the American prairies, the male and female specimens of which were first described as species of different genera (fig. 194, 6-9). Various methods of asexual reproduction are widely represented among cereals. In particular, vegetative propagation with the help of creeping rhizomes, as well as aerial shoots creeping and rooting in the nodes, is found in very many perennial grasses. Predominantly rhizomes reproduce, for example, common reed, in extratropical countries only rarely forms normally parted caryopses. Some ephemeroid grasses in arid regions of Eurasia, including Poa bulbosa and Calabrosella humilis, have bulbous thickened turf shoots. Later, during the dry season, their turf is broken by herbivores, and the bulbs are carried by the wind or on the legs of animals across the pasture.

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Asexual reproduction with the help of those parts or organs of the plant that are related to sexual reproduction is no less common in cereals. This includes viviparia, when a young plant develops not from a seed, but from spikelets modified into bulbous buds. Complete or almost complete transformation of all spikelets of a panicle into such buds is found in a number of Arctic cereals from the genera bluegrass, fescue, pike, as well as bulbous bluegrass, which is widespread in the arid regions of Eurasia. In all cases, viviparia can be seen as an adaptation to more severe habitats, although viviparous species and varieties can also arise as a result of hybridization between species.

Cases of apomixis in the narrow sense of this term or agamospermia, when a young plant develops from a seed, but without the fusion of gametes preceding its formation, is even more frequent, especially in the predominantly tropical tribes of millet and sorghum. Of the extratropical grasses, there are many apomictic and semi-apomictic species in the genera bluegrass and reed grass.

For cereals, highly specialized anemophilic plants, the daily rhythm of flowering and pollination is of particular importance. Accurate blooming of all individuals of a given species during any limited time of day significantly increases the chances of cross-pollination and is an important adaptation to increasingly perfect anemophilia. Among extratropical cereals, several groups of species are distinguished, differing in flowering time: with one-time morning flowering (the most numerous group), with one-time midday or afternoon flowering, with two-time morning and evening flowering (weaker evening), with round-the-clock flowering, with night flowering ... The latter is found in only a few extratropical grasses. However, in the hot and dry regions of the tropics, night blooming is known in many species, as it avoids overheating and rapid death of pollen during a hot day. Interestingly, in tropical grasses with nocturnal blooms, when outside the tropics, flowering shifts to early morning, as the danger of pollen overheating is reduced. In grasses that bloom at noon and in the afternoon, flowering occurs during the hottest part of the day. Pollen grains at this time shrink and die relatively quickly, however, such cereals are especially often characterized by the so-called explosive flowering, in which the massive and simultaneous opening of flowers occurs in a very short time - no more than 3-5 minutes. With portioned flowering, also typical of many cereals, not one, but several such flowering bursts occur during the day. It has been shown that even very closely related species, for example, steppe fescue: Welsh fescue (Festuca valosiaca) and false sheep (F. pseudovina), when living together, can be genetically completely isolated from each other, because they bloom at different times of the day. Thus, a certain daily flowering rhythm in cereals turned out to be a good species-specific systematic trait.

The unit of distribution of fruits - the diaspora - in cereals is usually anthetium: a caryopsis, enclosed in flowering scales with an adjacent segment of the spikelet axis. Much less often, naked (devoid of any scales) caryopses, whole spikelets, parts of a common inflorescence, the entire common inflorescence, or even the whole plant serve as diasporas. In the aforementioned small sheath, the kernels strongly protruding from the floral scales fall out of them and are carried by water during fluctuations in the river level associated with floods, rains, changes in the direction of the wind, etc. carried by the wind. In sporobolus, widespread in the tropics, sac-like kernels, when wetted with rain or dew, quickly swell, burst, and the seeds squeezed out of them, surrounded by sticky mucus, hang from the spikelets, sticking to animal hair and bird feathers. Large caryopses of many bamboo that fall out of spikelets are spread mainly by water currents during tropical showers, as well as with the help of birds. Berry-like caryopses of melokanna begin to germinate on the mother plant, without a dormant period, then fall on the wet soil with their sharp end downward and continue their development on their own. They can also spread with the help of birds and animals that eat them.

Distribution with the help of whole common inflorescences or their parts is also not very rare in cereals. Spike-shaped panicles of setaria verticillata, very tenacious due to the presence of backward-directed bristles on the surrounding spikelets, often cling to animal hair or human clothing along with the stems. The ears of many Aegilops species with large, protruding awns are easily entangled in the fur of animals, but can be carried over long distances by the wind. Groups of spikelets of maned barley (Hordeum jubatum), bearing very long and thin awns, can also be carried both by animals and by the wind. In the latter case, multiple groups of spikelets can interlock together to form a spherical tumbleweed that is carried by the wind over long distances, especially along highways. Many other grasses are spread by the wind in a tumbleweed-type, and the basis of the latter is made up of very large, widely and widely branched panicles. Examples of this kind are the Siberian bluegrass (Poa subfastigiata) or the Lower Volga bieberstein's zingheria (Zingeria biebersteinii). In the littoral Asian and Australian genus Spinifex (Spinifex, Fig. 211, 3), the female common inflorescences, which are almost spherical, fall off entirely, then roll by the wind along the sandy coast or swim in the water and, already lingering somewhere, gradually disintegrate. The method of spreading the wide-spread serpentine (Cleistogenes squarrosa), one of the characteristic plants of the steppes and deserts of Eurasia, is also very curious (Fig. 194, 2). Stems of this species, with fruits, are serpentinely bent and break off at their base. Adhering to each other, they form a tumbleweed that is easily carried by the wind, and the kernels gradually fall out not only from the apical panicle, but also from the axils of the stem leaves, where there are shortened branches with cleistogamous spikelets.

In cereals, the distribution of diasporas with the help of wind and animals is almost equally represented, and in many cases, diasporas can spread in both ways (for example, in the common feather grass Stipa capillata in the steppes of Eurasia). Apparently, in many groups of cereals, in the course of evolution, there was a transition from a predominantly zoochore mode of distribution to a predominantly anemochoic one. So, in the genus reed grass of the diaspora of more ancient, forest species (reed reed, etc.) have long, articulated bent awns and a bundle of short hard hairs on the callus - an adaptation to zoochoria, and the diasporas of a relatively younger species of terrestrial reed (Calamagrostis epigeios) are supplied with very with a short awn and a bundle of very long (longer than flowering scales) hairs on the callus, spreading exclusively anemochorno. Species often combined with feather grass, but more primitive genus chiy (Achnatherum) also have small zoochorny spreading diasporas, while among feather grass there are highly specialized anemochoric species with very long (40 cm and more), double geniculate and pinnate awns in the upper part. ... The long and sharp callus with upwardly directed stiff hairs enables feather grass diasporas to screw into the soil, as it were. In this case, the upper, horizontally located part of the awn is fixed among other plants, and its lower, twisted part is hygroscopic and, with changes in humidity, it curls, then unwinds, pushing the flowering scales with a weevil deeper and deeper into the soil. In some feather grass that can spread to animal hair, such as feather grass, diasporas can screw into their skin, causing serious damage to the animals.

The increase in the windage of the diasporas in anemochoric grasses is especially often carried out due to long hairs, which can be located on the sides of the lower floral scales (in the transylvanian pearl-tree - Melica transsilvanica), on the highly elongated callus of the lower floral scales (in the reed), on the segment of the spikelet axis above the base flowering scales (in many species of reed grass), on highly elongated awns (in many feather grass). In the common in the sandy deserts of Eurasia, the cirrus selin (Stipagrostis pennata) divides the spine into 3 feathery branches, resembling a parachute in its appearance. In many chloris species, the parachute device looks like a transverse row of long hairs in the upper part of the lower floral scales, and in the Persian nine-spine (Enneapogon persicus) it looks like a transverse row of 9 pinnate awns. Thick, but very light segments of ears of psammophilic genera - two-scaled (Parapholis) and one-scaled (Monerma) - are easily carried by the wind. The parity of diasporas consisting of a whole spikelet can increase due to winged spikelet scales (in canary grass - Phalaris) or due to their saccular swelling (in Beckmannia - Beckmannia). In the waggon (Briza), the windage of the anthecian diaspora increases due to the strongly expanded and almost entirely membranous lower floral scales.

The adaptations of cereals to the zoochoria are no less varied. Especially often, their antecia diasporas have articulated rough awns and hard hairs on the callus, however, in representatives of the genus Tragus and some other genera, hooked spines are arranged in rows on the dorsum of the lower floral scales. In the herbaceous bamboo leptaspis cochleata (Leptaspis cochleata), the closed and swollen lower floral scales that fall together with the caryopsis are covered with small hook-like spines curved at the apex and easily attach to animal hair (Fig. 197, 4). In the spiny bristle (Cenchrus), rather large spiny heads, consisting of several spikelets enclosed in a wrapper of expanded bristles that grow together in the lower part of the common inflorescence (Fig. 202, 8-9), are exozoochrically distributed (Fig. 202, 8-9). Fruiting spikelets of the tropical genus Lasiacis are spread by birds attracted by the oil-rich, thickened spikelet scales. Diasporas of many species of pearl barley (Melica) have juicy appendages of underdeveloped flower scales at the apex of the spikelet axis and are spread by ants eating these appendages.

Diasporas of many aquatic and coastal grasses (for example, zizania, manna, etc.) have good buoyancy and are easily carried by water flows, and some other species (for example, wild oats, Fig. 212) are capable of independent movement (autochory) due to hygroscopic twisting or untwisting the awns. At the present time, both the conscious and the unconscious role of man in the spread of cereals has increased enormously. The areas of cultivated species are expanding, often together with specific weeds. They are introduced into cultivation as fodder plants, and then many cereals from other continents run wild (for example, rootless wheatgrass or Elymus novae-angliae, introduced from North America, was widely spread in the USSR). Many types of cereals that have long been introduced into cultivation have lost the way of distribution characteristic of their ancestors. So, in cultivated species of wheat, rye, barley, the ears do not split into segments; cultivated oats have no joints on the spikelet axis; Chumiza and Mogar (Setaria italica) have no joints at the base of the spikelets, which are characteristic of wild-growing representatives of this genus. Only in culture are such cereals as corn and bead, incapable of reproducing without human help, are known.

When the caryopsis germinates, the embryonic root begins to grow first, and then the bud of the embryo, covered by the coleoptile. After the coleoptile emerges on the surface of the soil, the first leaf of the seedling protrudes from it, which continues to rapidly lengthen and takes on the shape characteristic of this species. In cereals, 2 main types of seedlings are distinguished: festucoid, when the first leaf of the seedling is narrow and almost vertically upward directed (it is found in festucoid tribes of cereals), and panicoid, when the first leaf of the seedling is wide (lanceolate or lanceolate-ovate) and almost horizontally deviated from the axis escape (it is known among the panicoid tribes). In addition, there is an intermediate eragrostoid type between them, and recently 2 more types have been identified - bamboo and orizoid, in which on the axis of the seedling, not ordinary leaves follow the coleoptile, but one or more cataphylls - scale-like leaves, and with bamboo In the type characteristic of the bamboo subfamily, the first fully developed leaf of the seedling is built according to the panicoid type, and in the orizoid type, characteristic of the rice subfamily, it is closer to the festucoid type.

The initial variants of the cereal system were based mainly on easily conspicuous signs in the structure of common inflorescences and spikelets. For a long time, the system of the well-known specialist in cereals - E. Gakkel (1887) was generally accepted. This system was built on the principle of gradual complication in the structure of spikelets, from tribes of sorghum and millet, usually with spikelets with one developed flower, to bamboo, many of which have multi-flowered spikelets of a very primitive structure. However, already at the beginning of the XX century. accumulated a lot of new data on the anatomy of leaves and stems, the structure of the embryo and seedlings, small details in the structure of flowers, the structure of starch grains, which made it possible to radically revise the Gakkel system. It became clear that the main direction in the evolution of the generative organs of cereals was not their complication, but, on the contrary, simplification: a decrease in the number of flowers in a spikelet, flower films, stamens and stigma branches.

The study of the chromosomes of cereals, associated with the rapid development of genetics, also provided important data for the construction of a new system. In the classic work of N.P. Avdulov, published in 1931, it was found that the size of chromosomes and their main number (x) in the family of cereals are signs not only of the constant limits of most genera, but also characteristic of larger subdivisions of this family. Relatively small chromosomes with a main number equal to 6, 9 and 10, turned out to be characteristic mainly of tropical tribes of cereals (sorghum, millet, porcine, etc.), and larger chromosomes with a main number of 7 - mainly extratropical tribes of bluegrass, oats, wheat and etc. In the system proposed by Avdulov, cereals were divided into 2 subfamilies - sugarcane (Sacchariflorae) and bluegrass (Poatae). The last subfamily, in turn, was divided into 2 series: reed (Phragmitiformis) with older tribes with small chromosomes, and fescue (Festuciformis) with most extratropical tribes of cereals with large chromosomes, usually in multiples of 7.

The Avdulov system became the basis for subsequent cereal systems, in which the bamboo subfamily (Bainbusoideae) took the first place. On the basis of the above characteristics, 5 more subfamilies were identified, one of which - rice (Oryzoideae) - occupies, as it were, an intermediate position between bamboo and other cereals, and the remaining 4 are bluegrass (Pooideae), reed (Arundinoideae), field grass ( Eragrostoideae) and millet (Panicoideae) - form a gradual transition from the full set of festucoid signs characteristic of extratropical cereals to the full set of panicoid signs characteristic of tropical cereals. It should be noted that the differences between the last 4 subfamilies were not so consistent as it seemed at first, as a result of which they are not recognized by all authors. Thus, among millet, there were a number of species (including those in the genus millet) with festucoid leaf anatomy (and, therefore, without the kranz syndrome). Among bluegrass, which are characterized by relatively large chromosomes with a main number of 7, there are genera with small chromosomes (for example, short-legged - Brachypodium) and genera with the main number of chromosomes 6 (canary grass - Phalaris), 9 (pearl barley) and 10 (mannik) ... Recently, in two festucoid cereals, Zingeria biebersteinii and Colpodium versicolor, the lowest total number of chromosomes (2n = 4) was found in higher plants, with the main chromosome number 2. Previously, this number was known only in one American species from the Asteraceae family. Even within the same festucoid species, the Mediterranean ephemera of the spring boron (Milium vernale), races with the main numbers of chromosomes 5, 7 and 9 have been identified.

Forest herbaceous plants Wikipedia -? Cingeria Bieberstein Scientific classification Kingdom: Plants Department: Flowering plants ... Wikipedia

Angiosperms (Magnoliophyta, or Angiospermae), a division of higher plants that have a flower. There are over 400 families, over 12,000 genera and probably no less than 235,000 species. According to the number of types of flowering plants. significantly surpass all the others ... ... Great Soviet Encyclopedia

To date, more than 350 thousand plant species are known. Of these, the class Monocotyledons accounts for about 60,000 species. Moreover, this class includes the two most common in terms of habitat and economic value of the family:

• Liliaceae.
• family Cereal or Bluegrass.

Let's take a closer look at the Cereals family.

Zlakov's taxonomy

The place in this family is occupied by the following:

Kingdom of the Plant.

Subkingdom Multicellular.

Department of Angiosperms (Flowering).

Class Monocots.

The Cereal family.

All representatives of this family are united in 900 genera. The total number of representatives is about 11,000 species. Plants of the Cereals family are found both meadow and cultivated, which are of great agricultural importance.

Growing conditions and distribution

The Cereals family occupies very extensive habitats due to its unpretentiousness, moisture and drought resistance (not all species). Therefore, we can say that they cover almost the entire land, with the exception of Antarctica and ice-covered territories.

This immediately makes it clear that plants of the Zlakov family are very unpretentious to growing conditions. So, for example, representatives of meadow grasses (timothy, bluegrass, wheatgrass, hedgehog, bonfire, and others) quite calmly endure the unfavorable conditions of winter and the heat of summer.

Cultivated plants (rye, oats, wheat, rice) are already more demanding, however, they are able to survive rather high air temperatures.

Almost all representatives, which include the Cereals family, are equally neutral to sunlight. Representatives of meadows, steppes, pampas, savannas are plants accustomed to harsh conditions, and cultivated species are constantly cared for and processed by humans, so they also feel comfortable in low light periods.

General characteristics of the family

The Cereals family includes both annuals and biennials, and most often perennials. Outwardly, they are usually similar, as they have similar leaves. Their stem has clear distinctive features from the stems of other plants - it is completely empty inside and is a hollow tube, which is called a straw.

The large number of representatives of the family is explained by their importance in economic terms: some plants are used for livestock feed, others for processing and obtaining grain and starch, others for obtaining protein, and others for decorative purposes.

Morphological signs

The external (morphological) features of the Cereals family can be described in several points.

1. Stalk of straw (except for corn and cane), hollow inside.
2. The internodes on the stem are well defined.
3. In some representatives, the stem lignifies during life (bamboo).
4. The leaves are simple, sessile, with a pronounced sheath, covering the stem.
5. elongated,
6. The arrangement of the sheet plates is alternate.
7. type, sometimes underground shoots turn into rhizomes.

All representatives of the Cereals family possess such characteristics.

Flower formula

During the flowering period, the plants of this family are very unremarkable, as they are prone to self-pollination or cross-pollination. Therefore, it makes no sense for them to form huge bright and fragrant flowers. Their flowers are small, pale, completely inconspicuous. They are collected in inflorescences of different types:

• complex ear (wheat);
• cob (corn);
• panicle (feather grass).

The flowers are the same for everyone, the formula of a flower of the Zlakovy family is as follows: TsCH2 + Pl2 + T3 + P1. Where CC - flower scales, P - films, T - stamens, P - pistil.

The formula of the flower of the Zlakov family gives a clear idea of ​​the nondescriptness of these plants during the flowering period, which means that they are not used for decorative purposes, but leaves and stems.

Fruit

After flowering, a fruit rich in protein and starch forms. It is the same for all representatives of the Cereal family. The fruit is called the caryopsis. Indeed, most people far from biology know the term "cereals" itself, and it is associated with grains of agricultural plants called cereals.

However, not only cultivated plants of the Cereal family have such a fruit, but also meadow ones. Grains are rich in vitamins, gluten, protein, starch.

Representatives of the Zlakovs

As mentioned above, there are about 11,000 plants in total that form the Cereal family. Their representatives are found among wild and cultivated plant species.

Wild-growing representatives:

• timothy;
• bonfire;
• feather grass;
• wheatgrass;
• bamboo;
• wheatgrass;
• fescue;
• wild oats;
• bristle and others.

Most of the representatives of wild Zlakovyh are inhabitants of steppes, meadows, forests, savannas.

Cultivated plants that form the Cereal family produce their fruit under the influence of different environmental conditions. That is why, in order to get grain of decent quality, many of the Zlakovs were turned into home crops, which are properly cared for. These include:

• rye;
• wheat;
• sugar cane;
• oats;
• millet;
• barley;
• sorghum;
• corn and others.

Cultivated plants are of great economic importance for the fodder base of the entire country.

Annual plants

Annual plants include those that go through the entire life cycle in one that is, all the main life processes - growth, flowering, reproduction and death - fit into one season.

It is difficult to cite a single annual plant of the Zlakov family as an example. There are actually quite a few of them. Consider a few of the most common and commercial value.

1. Kaoliang. A plant from the genus Sorghum, it is on a par with rye, wheat and so on.
2. Durra or Jugarra. It is also a fodder plant that is most widespread in the southern parts of the Earth. It is used not only as a grain crop, but as hay and silage to feed animals.
3. Bonfire. A widespread plant of the Cereal family, which is often mistaken and regarded as a weed. It grows on any soil, is unpretentious to heat and moisture, can do without sunlight for a long time. It is used only for animal nutrition, its fruits are not of economic importance.
4. Corn. One of the most widespread agricultural crops in many countries of the world. Oil and flour are obtained from corn grains, and boiled grains are used directly.
5. Foxtail. Herbaceous plant belonging to both annual and perennial forms. The main significance is the formation of grass cover in meadows (flooded). Goes to feed animals.
6. Panic. A southern agricultural annual crop, which is grown not only for livestock feed, but also as a food plant to obtain valuable grain. It is thermophilic and photophilous, does not grow on the territory of Russia.
7. Bluegrass. There are several varieties of this genus, but they are all steppe or meadow grasses that are of industrial importance as livestock feed.
8. Millet. Includes many types. Of all the variety in Russia, there are only 6 species, some of which are used for decorative purposes. The second part is used to obtain nutritious grains for animal feed.

Perennial plants

Most of the plants in the family are perennial. That is, they consist of several seasons (growing seasons). They are able to survive the unfavorable conditions of winter periods without loss of vitality. Many of them form the Cereal family. The characteristics of such plants are very extensive. Consider some of the most economically important representatives.

1. Wheat. The most widespread agricultural crop in the world, which is valued for the nutrients of its grain.
2. Wheatgrass. Many people know him as a malicious weed. However, this is not its only meaning. This plant is a valuable food source for animal nutrition.
3. Rice. A very important agricultural crop, which is not inferior to wheat in terms of value and nutritional value of grain. Cultivated in the Eastern regions of the world.
4. Rye. One of the most demanded cereals after wheat and rice. A large number of these plants are grown here in Russia. The nutritional value of the grain is at a high level.
5. Sugar cane. His homeland is India, Brazil and Cuba. The main nutritional value of this crop is sugar extraction.

Agricultural crops of the Zlakovykh

In addition to those listed above, sorghum can also be attributed to agricultural crops of this family. This plant has all the characteristics of the Cereals family, and also has a valuable grain. Sorghum is not grown in our country, as it is a very thermophilic plant. However, in the countries of Africa, Australia, South America, this is a very valuable commercial crop.

Sorghum grains are ground into flour, and parts of the stem and leaves go to livestock feed. In addition, furniture is made from leaves and stems, beautiful interior items are woven.

Barley can also be classified as an important agricultural crop. This plant does not require special growing conditions, therefore it is easily cultivated in the territories of many countries. The main value of the grain goes to brewing, obtaining pearl barley and barley, and also goes to animal feed.

Also, barley infusions are of great importance in folk and traditional medicine (remedies for diseases of the liver and gastrointestinal tract).

Nutritional value of cereal grain

Why are the grains of the representatives forming the Cereals family so important and widely applicable? The characterization of the grain composition will help to understand this.

Firstly, all Cereal grains contain protein, just the amount of it varies from one representative to another. Wheat varieties are considered the highest in gluten protein content.

Secondly, cereal grains contain starch, which means they have sufficient nutritional value and are able to form flour.

Thirdly, such a culture as rice contains a lot of vitamins of different groups, which makes it even more useful.

It is obvious that the full use of cereals supplies the body with a set of all the daily necessary substances. That is why they are so popular all over the world.

Cereals are not only well-known agricultural crops. There are those that grow freely and are of no benefit to humans, as well as types that are used for design.

Description of cereals and their significance for humans

The fruit of cereal plants is a monocotyledonous grain seed that has grown together with the shell. Leaves are long, with parallel venation, narrow, two rows. The stem is hollow, thin. Usually long. Inflorescences are paniculate, spikelet or racemose.

The value of cereal plants is great, it was from them, even in ancient times, that people learned to make bread and cereals. At first, bluegrass (the second name of the family of cereals) did not pay much attention until they realized that their fruits can be ground into dust, that is, into flour. Dough was made from flour, and cakes were baked from the dough, since there were no loaves and loaves of today. Later, cereals began to have not only nutritional, but also medical significance due to the contained useful substances. In addition to cultivated plants that benefit humans, there are weeds that are harmful to agriculture, as well as perennial grasses that are completely harmless.

Cultivated cereals

Over time, people realized that not all cereals are edible and suitable for cooking. They were looking only for those whose grains made delicious food. That is, it was precisely cultivated cereals that were needed. Also, the person realized that it is not necessary to collect something somewhere.

Look for suitable plants, walk each time and find out: where they grow and in what quantity. Then take the seeds, carry them home and so on in a circle. After all, you can start cultivating cereal plants near your own home. Plant the fruits, water and wait for them to sprout, plants will grow from them and ripen.

New fruits were harvested, some were left to grind, and some for the next sowing. This is how agriculture developed. New varieties of cereals were bred, which should be resistant to droughts and other negative influences. The breeders took into account the formula of the flower of cereals, in order to predict the genetic structure of new plants, to draw up a similar formula.

The altered individuals were subjected to careful research. The main goal of breeders is to create perfect varieties. These plants must be absolutely resistant to drought, weeds and other adverse influences. Each variety has its own name.

List of cultivated, weeds and herbaceous plants

Bluegrass are subdivided into three main categories: grains, weeds, and grasses. Some of the same types are used for decoration.

Not all representatives are represented in the lists, but several well-known cultivated, weed and herbaceous species. In fact, there are many more of them.

Cereals:

• common millet;
• oats;
• barley;
• corn;
• rye;
• wheat.

• creeping wheatgrass;
• chicken millet;
• rye fire;
• annual bluegrass.

• feather grass;
• spikelet;

It is not necessary to call all cereal grasses weeds that grow freely in meadows. They are the main food for livestock and poultry.

Photos and names of cereals

Cultivated cereals are specially grown for use as a food product. In writing I use whole and crushed grains, flour and pastries from it.

Millet

Millet is a plant that tolerates heat and drought well. Common millet is of value, it is from its seeds that millet is extracted. Homeland - Southeast Asia. It is grown everywhere, including on saline soils. High acidity is the only weakness of millet, it cannot stand it and dies. The grains are used for making cereals, soups, and also as feed for poultry.

Oats

An annual plant that is widely used in agriculture. It is resistant to negative environmental conditions, it can be grown on those lands where it is cold enough. Originally from some provinces of East China, Mongolia. Previously, it was perceived by farmers as a weed, but its fodder properties refuted this opinion. Later they learned to make various pastries from it, and the Germans brewed the so-called white beer. It can be filmy and naked. The latter is less common than the former and requires a lot of moisture.

Barley

One of the most important cereal crops, developed relatively recently, about seventeen thousand years ago. The inhabitants of the Middle East were among the first to notice about its benefits. Bread made from barley flour is heavier, rougher than wheat, but it is considered a healthier product even now. The plant is one-flowered, pollinated independently. Nowadays, barley is grown for both fodder and food needs. Barley beer is also common among connoisseurs of this product.

Corn

Also called maize or sweet corn. It is used for feed and food needs. Of the entire genus, this is the only representative of cultivated cereals. It differs from other species of the whole family by a large ear with yellow seeds. Country of origin - Mexico.

In terms of sales, it is in second place after wheat. It is used to make cornstarch, canned food, and even medicines.

Rice

An annual herb. Requires special attention, the plant is capricious, needs a lot of moisture. Grown in Asian countries, but some types of rice - in African countries. Rice fields are made so that they can be flooded with water (protected from sunlight) while the plant is ripe, but then drained to harvest. They make cereals, starch from grains. If the kernels are germinal, then they are great for making rice oil.

Alcohol and medicines are made from rice. Rice straw is used to make paper, and the husk is used to make feed bran.

Rye

Nowadays, winter rye is mainly used for sowing, since it is more resistant to adverse conditions. An unpretentious plant, unlike wheat, rye is not particularly sensitive to soil acidity. The best soil for growing is black soil. It is used for the production of flour, kvass and starch. Weed grass rye easily suppresses, which greatly facilitates the fight against harmful factors for cultivation. The plant is biennial and annual. Most popular in Germany.

Wheat

In the first place in terms of cultivation and sale is this particular grain crop. Bread of the highest grade is baked from wheat flour, confectionery and pasta are produced. Wheat is also used in the production of beer and other alcoholic beverages. It is grown on almost all lands, except for territories belonging to the tropical zone. Includes about ten types.

Many people believe that yellow spikelets with long mustaches are wheat. However, it is not. Wheat has grayish spikelets, fewer grains, and short whiskers.

Photos and names of weeds

A person has to fight against weedy cereals. Many of these plants are used as animal feed.

Creeping wheatgrass

Easily displaces cultivated plants. It is very tenacious, capable of drawing juices from the ground that are needed by other species. The roots are powerful, more powerful than those of cultural representatives. Feels very good on wet, fertile soil.

Chicken millet

Chicken millet or barnyard. It bears this name due to the fact that this plant is very similar to its cultivated relatives. It is distinguished by its large size and large leaves, which require a lot of nutrients. Naturally, it is forced to rob other plants and take everything for itself.

Rosichka

The dewdrop, especially the blood red, has the same ability to survive as other weeds. May exist in acidic soils. It has a lot of seeds in its paniculate spikelets. For them to germinate, only two degrees of heat is enough.

Rye bonfire

It can be easily confused with rye, but the survival rate is slightly higher. Drought-resistant. Inhabits rye fields. When its seeds are mixed with the seeds of a cultivated relative when harvested, the quality of the crop is reduced.

Gumay

It also has a different name - Alepskoe sorghum. It is one of the most dangerous plants and poses a serious threat to cereal crops. It survives well during droughts, but despite this, sorghum is very demanding on moist and fertile soil. Has a powerful rhizome for constant nutrient intake.

Spit multicolor

It affects legumes and cereals. The chaff is widespread everywhere. Survives well in adverse conditions. The plant is strong, can reach one meter in height. Prefers nitrogenous soils.

Annual bluegrass

Another representative of cereal weeds that harm agriculture. It grows in fields, mainly where grain crops are cultivated. Annual bluegrass is resistant to negative influences. This annual plant is widespread in Central Asia, Western Siberia, and also in the Caucasus.

Photos and names of cereal herbs

Grasses can become a decoration of our summer cottages if you learn how to use them correctly.

Quaking grass

It grows mainly in the meadows of Europe. It resembles a bush with panicles of flattened spikelets. Loves sunlight and moderate moisture. Excellent as food for cattle and.

Pearl barley

It is so called because its seeds are very similar to pearl barley. Perennial plant growing in forests, sometimes in steppes. It can often be found along the shores of lakes and swamps. Includes several varieties.

Feather grass

Inhabits European steppes, meadows. It has a long thin spikelet resembling a light gray thread from a distance. Very well suited as feed for farm animals. He needs sunny, neutral soils. Pollinated on its own.

Kolosnyak

Grows in the southern parts of Europe. It has a long root as it grows on sandy soils. The plant is massive, with long thick spikelets. The color of the leaves is blue-green.

Molinia

Large perennial plant. It is found in forests, swamps, as well as along the banks of rivers and lakes. It looks like a bush with straight leaves. Spikelets are paniculate, large, dark purple in color. Grows in the European part of the continent, in sunny areas or surfaces with moderate shade. It is often used as an ornamental plant.