Today, more than 350 thousand plant species are known. Of these, the Monocot class accounts for about 60,000 species. Moreover, this class includes the two most widespread families in terms of habitat and economic importance:

• Liliaceae.
• family Poaceae or Poagrass.

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

Taxonomy of Cereals

The place in this family is occupied by the following:

Kingdom of Plants.

Subkingdom Multicellular.

Department Angiosperms (Flowers).

Class Monocots.

Family Cereals.

All representatives of this family are combined into 900 genera. The total number of representatives is about 11,000 species. Plants of the Poaceae family are found both as meadow and cultivated plants, which are of great agricultural importance.

Growing conditions and distribution

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

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

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

Almost all representatives, which include the Poaceae family, are equally neutral towards sunlight. Representatives of meadows, steppes, pampas, and savannas are plants accustomed to harsh conditions, and cultivated species are subject to constant care and processing by humans, so they also feel comfortable during periods of low light.

General characteristics of the family

The Poaceae family includes both annual and biennial and most often perennial plants. Outwardly, they are usually similar, as they have similar leaves. The stem has obvious 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 to feed livestock, others are used for processing and obtaining grain and starch, others are used to obtain protein, and others are used for decorative purposes.

Morphological characteristics

External (morphological) characteristics of the Poaceae family can be described in several points.

1. The stem of a culm (except corn and cane), hollow inside.
2. The internodes on the stem are well defined.
3. In some representatives the stem becomes woody 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 the same.
7. like, sometimes underground shoots turn into rhizomes.

All representatives forming the Poaceae family possess such characteristics.

Flower formula

During the flowering period, 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. Collected in inflorescences of different types:

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

The flowers are the same for all, the formula of the flower of the Poaceae family is as follows: CC2+Pl2+T3+P1. Where TsCh - flower scales, Pl - films, T - stamens, P - pistil.

The formula of a flower of the Poaceae family gives a clear idea of ​​the inconspicuousness of these plants during the flowering period, which means that leaves and stems, rather than flowers, are used for decorative purposes.

Fruit

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

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

Representatives of Cereals

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

Wild representatives:

• Timothy grass;
• bonfire;
• feather grass;
• wheatgrass;
• bamboo;
• wheatgrass;
• fescue;
• wild oats;
• bristlecone and others.

Most representatives of wild cereals are inhabitants of steppes, meadows, forests, and savannas.

Cultivated plants that form the family Cereals produce their fruit under the influence of different conditions environment. That is why, in order to obtain grain of decent quality, many of the representatives of Cereals have been 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 food supply of the entire country.

Annual plants

Annual plants include those that go through their 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 just one annual plant of the Poaceae family as an example. There are actually quite a lot of them. Let's look at several of the most common and commercially important ones.

1. Kaoliang. A plant from the genus Sorghum, it is on a par with rye, wheat, and so on.
2. Durra or Jugarra. Also a forage plant, most widespread in the southern parts of the Earth. It is used not only as a grain crop, but as hay and silage for animal nutrition.
3. Bonfire. A widespread plant of the Poaceae family, which is often accepted and regarded as a weed. It grows on any soil, is unpretentious to heat and moisture, and can survive for a long time without sunlight. It is used only for animal nutrition; its fruits have no economic significance.
4. Corn. One of the most common agricultural crops in many countries of the world. Oils and flour are obtained from corn grains, and the grains themselves are used in boiled form.
5. Foxtail. A herbaceous plant belonging to both annual and perennial forms. The main significance is the formation of grass cover in meadows (flooded). Goes to animal feed.
6. Panic. A southern agricultural annual crop that is grown not only for livestock feed, but also as a food plant to produce valuable grain. Heat-loving and light-loving, does not grow in Russia.
7. Bluegrass. There are several varieties of representatives of this genus, but all of them are steppe or meadow grasses that are of industrial importance as livestock feed.
8. Millet. Includes many species. Of all the diversity in Russia, there are only 6 species, some of which are used for decorative purposes. The second part is used to obtain nutritious grain for animal feed.

Perennials

Most of the plants in the family are perennials. That is, they consist of several seasons (growing seasons). They are able to survive adverse conditions winter periods without loss of viability. Many of them form the Poaceae family. The characteristics of such plants are very extensive. Let's look at some of the most economically important representatives.

1. Wheat. The most widespread agricultural crop in terms of area occupied in the world, it is valued for the nutrients of its grain.
2. Wheatgrass. Many people know it as a nasty weed. However, this is not its only meaning. This plant is a valuable food supply for animals.
3. Rice. A very important agricultural crop, not inferior to wheat in terms of grain value and nutritional value. Cultivated in the Eastern regions of the world.
4. Rye. One of the most popular grains after wheat and rice. A large number of these plants are grown here in Russia. The nutritional value of the grain is high.
5. Sugar cane. Its homeland is India, Brazil and Cuba. Main the nutritional value This crop is the extraction of sugar.

Agricultural Crops Cereals

Agricultural plants of this family include, in addition to those listed above, sorghum. This plant has all the characteristics of the Cereal family, and also has valuable grain. Sorghum is not grown in our country, as it is a very heat-loving plant. However, in African countries, Australia, South America This is a very valuable commercial crop.

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

Barley can also be considered an important agricultural crop. This plant does not require special conditions for growth, so it is easily cultivated in many countries. The main value of the grain is spent on brewing, producing pearl barley and barley, and also goes to animal feed.

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

Nutritional value of cereal grains

Why are the grains of the representatives that form the Cereal family so important and widely applicable? Characteristics of grain composition will help to understand this.

Firstly, all cereal grains contain protein, it’s just that the amount varies among different representatives. Wheat varieties are considered to have the highest gluten protein content.

Secondly, cereal grains contain starch, which means they have sufficient nutritional value and are capable of forming flour.

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

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

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 large role they play in the composition of herbaceous vegetation groups - meadows, steppes, prairies and pampas, as well as savannas. Cereals include the main food plants of mankind - soft wheat (Triticum aestivum), rice (Oryza sativa) and corn (Zea mays), as well as many other grain crops that supply us with such necessary products as flour and cereals. Perhaps no less important is the use of cereals as feed plants for domestic animals. The economic importance of cereals is also diverse in many other respects.

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

Cereals are characterized by a relative uniformity of their distribution on Earth. In tropical countries this family is about as rich in species as in temperate countries, and in the Arctic the cereals rank first among other families in the number of species. Among the 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) are rich in endemic cereals species). Cereals are usually easy to recognize by their appearance. They usually have articulated stems with well-developed nodes and two-rowed alternate leaves, divided into a sheath covering the stem, a linear or lanceolate blade with parallel venation, and a membranous outgrowth located at the base of the blade, called a ligule or ligula. The vast majority of cereals are herbaceous plants, however, many representatives of the bamboo subfamily (Bambusoideae) have tall, highly branched in the upper part, with numerous nodes, stems that become heavily lignified, however, retaining the structure typical of cereals. In 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 40 m tall stem is as tall as many trees. Among bamboo, climbing or climbing, sometimes thorny liana-like forms are also known (for example, Asian Dinochloa - Dinochloa). The life forms of herbaceous cereals are also quite diverse, although outwardly they appear to be the same. Among the cereals there are many annuals, but they significantly predominate perennial species, which may be turfy or have long creeping rhizomes.

Like most other monocots, grasses are characterized by a fibrous root system, which is formed as a result of underdevelopment of the main root and its very early replacement by adventitious roots. Already during seed germination, 1 to 7 such adventitious roots develop, forming the primary root system, but after a few days, secondary adventitious roots begin to develop from the lower adjacent nodes of the seedling, from which the root system of an adult plant is usually composed. In cereals with tall, erect stems (for example, 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 is located, consisting of closely spaced nodes. In the axils of the leaves extending from these nodes, buds are formed, giving rise to lateral shoots. According to the direction of growth, the latter are divided into intravaginal (intravaginal) and extravaginal (extravaginal). When an intravaginal shoot is formed (Fig. 192, 1), the axillary bud grows vertically upward inside the sheath of its covering leaf. With this method of shoot formation, very dense turfs are formed, as in many species of feather grass (Stipa) or fescue (Festuca valesiaca). The bud of the extravaginal shoot begins to grow horizontally and pierces the sheath of the covering leaf with its apex (Fig. 192, 2). This method of shoot formation is especially characteristic of species with long creeping underground shoots-rhizomes, for example, creeping wheatgrass (Elytrigia repens). However, there are frequent cases when extravaginal shoots quickly change the direction of their growth to vertical, as a result of which turfs are formed that are no less dense than with the intravaginal method of shoot formation. In many cereals, mixed shoot formation is also known, when each plant produces shoots of both types (Fig. 192).

Branching of stems in their middle and upper parts is rare in grasses from extratropical countries and usually only in species with stems creeping along the ground (for example, in the coastal plant - Aeluropus). Much more often it can be seen in cereals of the tropics, and their lateral shoots usually end in inflorescences. Turfs of such cereals often resemble bouquets or brooms in appearance. Stems that are especially strongly branched in the upper part are characteristic of large bamboo trees, and they even have a whorled arrangement of lateral branches, for example, in some Central American species of bamboo - Chusquea (Fig. 193, 5). Many grasses with creeping and rooting above-ground shoots at nodes, for example, bison grass (Buchloé dactyloides) of the North American prairie (Fig. 194, 6), can form large clones that cover the soil with a thick carpet. Also in the North American Muhlenbergia torreyi and some other species, such clones grow along the periphery and die off in the middle, forming something like “witch’s rings” in some types of mushrooms.

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 begin to flower. Elongated reproductive shoots are formed from them after the emergence of the primordium of the general inflorescence due to the rapid intercalary growth of internodes. In this case, each segment of the cereal shoot grows independently under the protection of the leaf sheath, having its own zone of intercalary meristem. The pith in growing internodes usually dies quickly and they become hollow, but in many cereals of tropical origin (for example, corn), the pith is not only preserved throughout the stem, but also has scattered vascular bundles. Many bamboo-like vines also have internodes filled with pith. Sometimes, during the transition to an elongated reproductive shoot, only the uppermost internode, located under the inflorescence, lengthens, for example, in the blue molinia (Molinia coerulea).

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

Signs anatomical structure stems are used in the taxonomy of cereals. Thus, most extratropical grasses, usually called festucoid (from Festuca - fescue), are characterized by internodes of stems with a wide cavity and an arrangement of bundles of conductive tissue in 2 circles (the outer one of smaller bundles), and for predominantly tropical ones - panicoid (from Panicum - millet) - internodes with or without a narrow cavity and with the arrangement of vascular bundles in many circles.

The leaves of cereals are always arranged alternately and almost always in two rows. 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 present on the rhizomes, and often also at the base of above-ground shoots. In many bamboo trees, falling scale-like leaves without blades or with very small blades are often located along almost the entire length of the main shoot. The scales have a predominantly protective significance and usually follow the very first leaf-shaped organ of the shoot - always a scale-like and usually two-keeled preleaf.

In ordinary, assimilating leaves, the sheath is formed by the base of the leaf that has grown in the form of a sheath enveloping the stem and serves as protection for the growing internode. The sheaths of cereals can be either split to the base (for example, in the predominantly tropical tribes of millet - Paniceae and sorghum - Andropogoneae), or fused at the edges into a tube (in the tribes of brome - Bromeae and pearl barley - Meliceae). In some species of steppes and semi-deserts (for example, in the 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, dead sheaths of the lower leaves protect the base of the shoots from excessive evaporation or overheating. When the vascular bundles of the sheaths are connected to each other by strong anastomoses, a mesh-fibrous sheath is formed at the base of the shoots, characteristic, for example, of the coastal brome (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, a membranous or thin-skinned outgrowth - a 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 bent subfamily (Eragrostoideae), it is modified into a series of densely located hairs. In most species of the widespread genus Echinochloa and in the North American genus Neostapfia, the uvula is completely absent and the vagina merges into a plate without a clearly defined boundary between them. On the contrary, the Mexican Muhlenbergia macroura has very long (2-4 cm) tongues. At the top of the vagina on the sides: from the uvula, some grasses (especially bamboo) have 2 lanceolate, often crescent-shaped outgrowths called ears.

In the vast majority of cereals, the leaf blades have parallel veins, a linear or linear-lanceolate shape, 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 two African genera - Phyllorachis and Umbertochloa - they are even arrow-shaped at the base (Fig. 196, 10) . In the bamboo subfamily, the leaf blades are usually lanceolate and narrowed at the base into a more or less developed petiole. In the Brazilian herbaceous bamboo Anomochloa, the leaf blades are heart-shaped and connected to the sheaths by a petiole up to 25 cm long (Fig. 197, 7). The leaves of another American genus, Pharus, also have very long petioles, which have another feature not characteristic of other cereals - pinnate venation of the blades. In most bamboo, as well as in some broad-leaved 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 arranged leaves rarely exceed 1 cm in length, and in the South American bamboo neurolepis elata they are up to 5 m long and 0.6 m wide. Very narrow, bristly folded along or Many types of feather grass, fescue, and other, usually xerophilic grasses have folded leaf blades. In the African miscanthidium teretifolium, very narrow plates are represented almost by the midrib alone.

The anatomical structure of leaf blades as a systematic character 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 anatomical structure of leaf blades: festucoid, bamboozoid (from Bambusa - bamboo), arundinoid (from Arundo - arundo), panicoid, aristidoid (from Aristida - triostida) and chloridoid or eragrostoid (from Chloris - - chloris and Eragrostis - bent grass). The festucoid type (mainly extratropical tribes of cereals) is characterized by a disordered arrangement of chlorenchyma, a well-developed internal (sclerenchyma) and relatively weakly demarcated external (parenchyma) lining of vascular bundles (Fig. 198, 1). The bamboozoid type, characteristic of the bamboo subfamily, is in many ways similar to the festucoid type, but differs in chlorenchyma, consisting of peculiar lobed cells located in rows parallel to the epidermis, as well as an outer covering of vascular bundles that is more separate from chlorenchyma (Fig. 198, 2). With the arundinoid type, characteristic of the reed subfamily (Arundinoideae), the inner lining of the bundles is poorly developed, and the outer one is well developed and consists of large cells without chloroplasts; chlorenchyma cells are located densely and partly radially around the bundles. The remaining types (mainly the tropical subfamilies bentgrass and millet) are characterized by a radial (or crown) arrangement of chlorenchyma around the vascular bundles, and in the chloridoid type the internal (sclerenchyma) lining 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 the radial (crown) arrangement of chlorenchyma and the well-separated outer (parenchyma) lining of the vascular bundles are associated with many other physiological and biochemical features (the so-called kranz syndrome, from German kranz - wreath), primarily a special method of photosynthesis -- C4 pathway of carbon dioxide fixation, or cooperative photosynthesis, based on the cooperation of chlorenchyma cells and parenchyma sheaths that perform different functions. Compared to the usual C3 by fixing carbon dioxide, this path is very economical in terms of moisture consumption and is therefore beneficial when living in arid conditions. The advantages of kranz syndrome can be seen in the example of the species of bentgrass (Eragrostis), bristleweed (Setaria) and lyricist (Crypsis) in the southern regions of the USSR: the maximum development of these species occurs in the driest time of the year 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 anatomical structure of the leaves are also clearly 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 very thick walls, and at the ends, on the contrary, they are expanded with thin walls. This structure allows you to regulate the width of the stomatal fissure by expanding or narrowing the thin-walled parts of the guard cells.

Cereal flowers are adapted to wind pollination and have a reduced perianth, stamens with long flexible filaments and anthers hanging on them, long feathery stigmas and completely dry pollen grains with a smooth surface. They are collected into elementary inflorescences very characteristic of cereals - spikelets, which, in turn, form general 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 bear flowers in their axils, are called spikelets - lower and upper (usually larger), and the higher located scales with flowers and their axils are called lower floral scales. Both are homologous to leaf sheaths, with the lower lemmas often bearing awn-like appendages that are generally considered homologous to leaf blades. Some bamboo have more than two glumes, and in the leaf glume (Phyllostachys) such glumes often bear small leaf blades (Fig. 200, 7). On the contrary, in some herbaceous cereals one (in the chaff - Lolium) or both (in the sheath - Coleanthus, Fig. 201, 6) glumes can be completely reduced. True glumes are in origin the upper leaves, and not bracts (bractea), like the lower glumes. However, in many cases (especially in the millet tribe) the reduction of flowers in the axils of the lowermost lemmas makes the latter very similar to additional glumes. The spikelets and lower floral scales of the most primitive bamboo have, like the leaf sheaths, a large and variable number of veins, which during 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 two-spikelet - Trachynia - up to 30 flowers, Fig. 201, 14, 15) to constantly one (in reed grass or foxtail) or two (in calamus - Aira ). Chinese bamboo (Pleioblastus dolichanthus) has very primitive multi-flowered spikelets with a highly elongated and often branched axis. Such spikelets are more similar not to spikelets, but to branches of a paniculate general inflorescence (Fig. 200, 1). Even less distinguishable are the spikelets in the general inflorescences of the tropical bamboo Melocanna. In the axils of the arranged lower flower scales, not 1, but 2 or 3 flowers are placed on lateral axes equipped with bracts. It is likely that the evolution of common inflorescences in cereals went 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 multifloral spikelet usually has articulations under each lower floral scale and, when fruiting, splits into segments. The base of the lower flower scale, fused with such a segment, forms a thickened callus, which can be long and sharp, like that of a feather grass. The part of the spikelet that includes one flower, the lemma and the adjacent segment of the spikelet axis is often called the anthecia. In single-flowered spikelets, there may be no articulation under the lower flower scale, and then the spikelets fall off entirely when fruiting.

Common inflorescences of cereals usually have the form of a panicle, often very dense and spike-shaped, a brush or spike. Only small specimens of two-spikelet (Fig. 201, 14), species of brome (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 abyssinica (Oxytenanthera abyssinica, Fig. 193, 1) or in the Mediterranean ephemerals of the hedgehog (Echinaria, Fig. 201, 11), and the sandbox (Ammochloa, Fig. 201, 7 ). In the thorny bristlecone (Cenchrus), the common inflorescence consists of several spiny heads (Fig. 202, 8, 9). The result of higher specialization of general inflorescences is the ordered arrangement of spikelets, one at a time 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 palmately (as in the pigweed - Cynodon, Fig. 194 , 4). With this arrangement of spikelets, especially characteristic of the millet, sorghum and pigwort tribes, some of the spikelets on spike-shaped branches (usually located on stalks next to sessile bisexual spikelets) may be male or even have only a rudiment of a flower. In Artraxon from the sorghum tribe, only a stalk with a barely noticeable rudiment of a spikelet remains from the spikelet on the stalk. Unisexual spikelets are generally 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 Pampas grass, or Cortaderia Sello - Cortaderia selloana, table 45, 3, 4).

In the axils of the lower floral scales on the side of the spikelet axis there is another scale, usually having 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 lemma, it is called the upper lemma. Previously, L. Chelakovsky (1889, 1894) and other authors took it for 2 fused segments of the outer circle of the perianth, but now most authors consider it to be the preleaf of a strongly shortened shoot located in the axil of the lower floral scale, carrying a flower. In some genera of grasses (for example, in foxtail), the upper floral scale can be completely reduced, and in the very original American herbaceous bamboo streptochaeta (Streptochaeta), it is split almost to the base.

Above the upper floral scale, on the flower axis of the vast majority of cereals, there are 2 small colorless scales, called floral membranes 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 bracts. The presence of a third, dorsal lodicule in many bamboo, as well as in the genera of the feather grass tribe, seems to confirm the first of these points of view, although the dorsal lodicule usually differs in structure from the two ventral ones, usually closely approximated and often connected to each other at the base.

The structure of the lodicules is considered an important systematic character characteristic of entire tribes of cereals (Fig. 203). Many bamboo plants have large scale-like lodicules with vascular bundles, where they have a predominantly protective function. In most other cereals, the lodicules have the appearance of small solid or bilobed scales, devoid or almost devoid of vascular 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 contribute to the spreading of the flower scales during flowering. Usually, there are 4 main types of lodicule structure: bambusoid, festucoid, panicoid and chloridoid, corresponding to the main types of leaf anatomy. Often there is also a melicoid type (from Melica - pearl barley), characteristic of the pearl barley tribe (Meliceae): very short (as if chopped off at the top) lodicules stick together with their anterior edges. The streptochaete mentioned above has 3 large, spirally arranged lodicules, but not all authors mistake them for lodicules. Finally, in many genera (including foxtail and sheathweed) the lodicules are completely reduced.

The most primitive number of stamens - 6 - is found among cereals only in many bamboo and rice plants (Oryzoideae). The vast majority of cereals have 3 stamens, and in some genera their number is reduced to 2 (in the fragrant spikelet - Anthoxanthum) or to 1 (in the cinnamon - Cinna). The number and structure of stamens varies greatly in the bamboo subfamily. Thus, in the South Asian genus Ochlandra, the filaments of stamens branch multiple times, as a result of which one flower can have up to 50-120 stamens. In the genera Gigantochloa and Oxytenanthera, the filaments of 6 stamens grow together into a rather long tube surrounding the ovary (Fig. 193, 3). Brazilian Anomochloa has 4 stamens. The filaments of cereal stamens can quickly elongate 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 a cereal flower. According to a more widely accepted point of view, the gynoecium of cereals is formed by 3 carpels fused 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 the other two carpels of the primarily 3-membered apocarpous gynoecium. The ovary is always unilocular with a single ovule, which can be orthotropic to hemitropic (rarely campylotropic) with a downward directed micropyle. The integument is usually double, but in the otherwise anomalous genus Melocanna it is simple. Usually the ovary transforms at the apex into 2 pinnately hairy stigmatic branches, but many bamboo can have 3 of them. The bare bases of the stigmatic branches vary greatly in length in different tribes. They are especially long in the predominantly tropical millet tribe, which is apparently due to more closely closed floral scales. In some cereals, the stigmatic branches may be fused with each other along their entire or almost entire length. Thus, in corn, only the upper parts of very long stigmatic branches are free, and in white beetle (Nardus), the ovary passes at the apex into a completely solid thread-like stigma, covered not with hairs, as in other cereals, but with short papillae. In bamboo - streptogyna (Streptogyna), the stigma branches covered with spines after flowering become very rigid and serve for the spread of grains (Fig. 204, 4).

The indehiscent dry single-seeded fruit of cereals, called the caryopsis, has a thin pericarp, usually so tightly adjacent to the seed coat that it appears fused with it. Often, when a caryopsis ripens, its pericarp sticks together with the flower scales tightly adjacent to it. In the sporobolus (Sporobolus), the pericarp remains separated from the seed and the caryopsis in this case is called sac-shaped. The shape of the grains varies from almost spherical (in millet) to narrow-cylindrical (in many feather grasses). On the convex, flat or concave in the form of a longitudinal groove, the ventral (ventral) side of the caryopsis has a scar, or hylum, usually more colored dark color in comparison with the rest of the caryopsis and having a shape from almost round (in bluegrass) to linear and almost equal in length to the entire caryopsis (in wheat). The hilum is the site of attachment of the ovule to the peduncle (funiculus), and its shape is determined by the orientation of the ovule.

The most original in their structure are the caryopsis of some bamboo, which can be berry-shaped with a thick fleshy pericarp or nut-shaped with a rather thick and very hard consistency pericarp, separated from the seed coat. In Melocanna, which is widespread in Southeast Asia, the berry-shaped caryopses are obverse 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 grain only a dry film remains between the pericarp and the greatly expanded scutellum.

In all other cereals, the majority of the mature grain is endosperm, and the ratio in the sizes of the endosperm and the embryo is of significant systematic importance. Thus, festucoid cereals are characterized by relatively small embryo sizes, while panicoid cereals are characterized by larger embryos compared to the endosperm. Typically, the endosperm of mature grains is hard in consistency, but it can be looser - mealy, when there is little protein in it, or denser - glassy when there is a relatively high protein content. It can be noted that the endosperm of cereal grains contains prolamin proteins, which are very characteristic of them and not found in other plants. In the grains 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 characterized by extraordinary resistance to drying, maintaining a semi-liquid consistency even in grains stored in herbariums for over 50 years.

Endosperm starch grains have different structures in different groups of cereals. Thus, 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 festucoid cereals they are also simple, but less variable in size and have a granular surface, while in fescue and many other festucoid cereals the starch grains are complex, consisting of smaller granules (Fig. 205).

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

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

The anatomical and morphological characteristics of cereals determine the very high plasticity and adaptability of representatives of this family to a wide variety of environmental conditions, which allowed them to spread throughout the entire landmass of the globe, right up to the most extreme limits of the existence of flowering plants. Grasses are found in almost all plant groups, although they are most typical for meadows, steppes and savannas various types. There are species that live on shifting sands (selina - Stipagrostis, sand-loving sand - Ammophila, etc.) and salt marshes (especially the coastal sand - Aeluropus and the sand grass - Puccinellia), both coastal and inland. Some species of anthrax grow in the strip flooded by tides, and one Arctic species confined to such habitats, the creeping anorak (P. phryganodes), often does not bloom, reproducing with the help of vegetative shoots that creep and take root in the nodes. The lowland and mountainous meadows of Eurasia are especially characterized by numerous species of the genera bluegrass, fescue, bentgrass (Agrostis), reed grass (Calamagrostis), foxtail, brome (Bromopsis), timothy grass (Phleum), shaker (Briza), etc. In the steppe zone and in the mountainous In the steppes of Eurasia, feather grass, fescue, thin-legged grass (Koeleria), wheatgrass (Agropyron), sheep grass (Helictotrichon), and in more southern regions - bearded vulture (Bothriochloa) become of leading importance. On the prairies North America Chloride grasses come to the forefront: Bouteloua, Chloris, buffalo grass (Buchloe dactyloides), etc. In arid regions of Asia, unique plant groups - common grass - are formed by the large turf grass (Achnatherum splendens). In the pampas of South America, pampas grass species play an important role. -- Cortaderia, forming giant tufts (Table 45, 3, 4).

In forests, the role of grasses in the vegetation cover is naturally less significant, however, even here, some species of this family can dominate the herbaceous layer. Thus, in the spruce forests of Eurasia, reed grass (Calamagrostis arundinacea) often grows in abundance, and in oak forests - bluegrass (Poa nemoralis), Elymus caninus, giant fescue (Festuca gigantea) and other species. Unlike steppe grasses, which are usually densely turfed and have very narrow, lengthwise folded leaf blades, forest grasses have less dense tufts and wider and less rigid leaf blades. Of the two species of pearl barley common in the deciduous and mixed forests of Eurasia, the more northern one, the drooping pearl barley (Melica nutans), belongs to the loose-turf grasses, and the more southern and therefore more xerophilic colored pearl barley (M. picta) belongs to the dense-turf grasses. Among tropical and subtropical forest grasses, many have recumbent or climbing densely leafy shoots and very wide, lanceolate or lanceolate-ovate leaf blades, reminiscent in appearance of the Tradescantia species widespread in greenhouse and indoor culture. Such a life form is found, for example, in representatives of the genus Oplismenus, one of whose species, O. undulatifolius, is found in the humid 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. Tree-like bamboo usually form large thickets along the banks of reservoirs, along watercourses descending from mountains, on the edges and clearings of tropical forests. Many herbaceous bamboo grow under the canopy of tropical rain forests and tolerate considerable shade. Aboveground shoots of tree-like bamboo are often considered homologous to the rhizomes of other cereals. They are characterized by extremely rapid growth and along their entire length they bear scale-like leaves - cataphylls, characteristic of the rhizomes of other cereals. All tree-like bamboos are evergreen plants, 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 blades.

Among bamboo with more or less lignified stems, two main life forms are distinguished, confined to different climatic conditions (Fig. 207). In most tropical bamboos, the development of which is natural conditions controlled by humidity levels (usually the onset of the rainy season), the stems are relatively close together, forming a kind of loose bush. Such bamboo have so-called pachymorphic (from the Greek “pachys” - thick) rhizomes: short and thick, sympodial, with core-filled asymmetrical internodes, 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 onset 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 usually have relatively small overall dimensions, although some types of bamboo can reach a height of up to 10 and even 15 m. The only bamboo genus growing wild in the USSR, Sasa, also has leptomorphic rhizomes, forming very dense and impenetrable thickets on the mountain slopes in the south Sakhalin and the Kuril Islands.

Herbaceous bamboo, like grasses of other subfamilies, bloom annually, but bamboo with woody stems, as a rule, bloom once every 30-120 years and after that they usually die, being obligate or facultative monocarpics. In 1969, massive and simultaneous flowering of the bamboo plant (Phyllostachys bambusoides), which is very widely cultivated there for technical purposes, was observed throughout almost all of Japan. This was a real disaster for those who grew it, since a significant part of the plantations died after flowering. Almost all Japanese psyllium 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 the perennial herbaceous grasses, especially tropical ones, there are gigantic forms, not inferior in height to many bamboo. These are, for example, common reed (Phragmites australis) and reed arundo (Arundo donax), which have multinodal but unbranched stems up to 3, sometimes up to 5 m high and long, highly branched rhizomes (Fig. 208, 3).

Reeds are one of the moisture-loving plants, forming large and almost pure thickets along the banks of reservoirs, and often in the water. Common reed is almost cosmopolitan and is widespread on all continents, both in the tropics and in warm temperate countries. This species has a fairly wide ecological range. It can also grow in swamps of various types, in swampy forests, on mountain slopes with groundwater inflows and in salt marshes, forming in extreme conditions of existence a unique form with shoots creeping along the ground and only vegetative ones. However, even in normally developed flowering reed clones, caryopses are not always formed and in small quantities, which is apparently due to the great antiquity of this species. Another giant grass, up to 3 m high, is pampas grass, or cortaderia, one of the species of which was introduced into the Mediterranean countries, forms very dense turf with intravaginal shoots (Table 45, 3, 4). Its narrow and very rigid leaf blades bear large spines along the edges and midrib, reminiscent in this respect of the leaves of the aquatic plant 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 top layer of soil. That is why among the steppe and desert grasses there are so many dense turf grasses (for example, brilliant grass, many types of feather grass, etc.). On the contrary, many meadow grasses belong to the long-rhizoma group, especially those living on loose, slightly turfed soils, for example, creeping wheatgrass and awnless brome (Bromopsis inermis), often growing in abundance in the meadows of riverine floodplains, as well as some coastal species, like reeds, forming dense thickets, for example, species of manna (Glyceria), reed grass (Scolochloa), broadleaf zizania (Zizania latifolia), etc. Among the species of the generally hydrophilic rice tribe (Oryzeae) there are also real aquatic plants. Such, for example, is the South Asian hygroryza aristata with short and wide leaves collected in rosettes floating on the surface of the water thanks to highly swollen sheaths.

A large and very interesting group of life forms in many respects is formed by annual grasses, which can be either spring, when seed germination begins in the spring, or winter, when seeds begin to germinate in autumn and young plants overwinter, continuing their development in the spring. Such a widely cultivated bread 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 consists of spring ephemerals. Quickly completing their life cycle during spring and 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 feed crops as wheat, rye, oats and barley come from ancient Mediterranean ephemerals.

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

Among annual cereals, species that are very original in appearance are known. Thus, in the double spikelet (Trachynia distachya) the general inflorescence consists of only 1-2 large multi-flowered spikelets (Fig. 201, 14); in the capitate barnyard grass (Echinaria capitata), the spikelets are collected into an almost spherical apical head, spiny at the fruit (Fig. 201, 11); in the eastern rhizome (Rhizocephalus orientalis) and the Palestinian sandpiper (Ammochloa palaestina), the spikelets collected in a thick head are located in the center of the leaf rosettes (Fig. 201, 1-7). In the latter species, known in the USSR only from the sands of the Absheron Peninsula, often almost the entire plant is covered with sand, from which only the tops of the leaves of the rosette are visible. Very interesting from a biological point of view is the late ephemeral small clamweed (Coleanthus subtilis), which lives on the coastal shallows of more or less large rivers. It develops very quickly after emerging from 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 glumes, 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 may even disappear for many years. It is distributed 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 the Amur.

The high specialization of cereal flowers for pollination by wind has already been noted above. However, 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 air movement is extremely small, are usually pollinated by insects, mainly flies and beetles, although such a secondary transition to entomophily is not yet associated with any special adaptations.

The vast majority of perennial grasses are cross-pollinated, and self-pollination is usually prevented by complete or partial self-sterility. However, among annuals there are a lot of facultatively self-pollinating species. These are, for example, all types of wheat and aegilops (Aegilops), as well as most types of brome (Bromus). Some cereals, in addition to the usual spikelets with chasmogamous flowers, also develop spikelets with cleistogamous flowers, pollinated with closed glumes. The formation of these spikelets guarantees the possibility of seed propagation under unfavorable weather conditions or when the plant is excessively nibbled by herbivores. Thus, in the widespread coastal grass Leersia oryzoides and the North American sporobolus cryptandrus, in unfavorable years only spikelets with cleistogamous flowers are formed and panicles do not protrude from the expanded sheath of the upper leaf. In the panicles of many feather grasses of the USSR flora in dry years only cleistogamous flowers are formed, and in cooler and more humid weather all or almost all flowers of the panicle bloom openly. Many Arctic grasses also flower primarily cleistogamously in particularly cold weather conditions.

In all species of the Eurasian genus 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-axle (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 is able to reproduce even in conditions of intensive pasture grazing, when every year all the turf is nibbled almost to the ground by cattle. At the same time, the grazing cattle breaks the turf with their feet and carries away the weevils of the nine-axe grass along with the lumps of earth stuck to them. Even higher specialization in this regard is observed in the North American amphicarpum. Its single spikelets with cleistogamous flowers are formed on the tips 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 the same spikelet along with bisexual flowers, for example, in the bison (Hierochloe) of 3 spikelet flowers, the upper one is bisexual, and the 2 lower ones are male, but more often they are located 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 sorghum tribe, the arrangement of spikelets on the spike-shaped branches of the general inflorescence in groups of 2 is very characteristic: one sessile with a bisexual flower, the other on a stalk - with a male flower. Bisexual, but with unisexual spikelets, the inflorescences of the South American herbaceous bamboo plant Piresia are located on creeping rhizome-like shoots, covered with scale-like leaves, and are often hidden under a litter of fallen leaves. Unfortunately, the method of flower pollination in species of this genus remains unknown. In the upper part of the panicle-shaped inflorescences of zizania there are larger spikelets with female flowers, in the lower part there are 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 cobs, located in the axils of the middle stem leaves and wrapped in sheath-shaped leaves (Fig. 209, 1-3). The arrangement of unisexual spikelets is even more original in the South Asian relative of corn - beadweed (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, horn-like or stony shell. By origin, this fruit is a modified sheath of the apical leaf. From its upper part emerge the long stigmatic branches of the female flower and the stem of the male part of the branch, which is a rather thick false spike (Fig. 210, 7).

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Examples of dioecious grasses include pampas grass (Cortaderia selloana, table 45, 3, 4) cultivated in gardens and parks in the south of the USSR and bison grass (Buchloe dactyloides) from the American prairies, male and female specimens of which were first described as species of different genera (Fig. 194, 6-9). Various methods of asexual reproduction are quite widely represented among cereals. In particular, vegetative propagation with the help of creeping rhizomes, as well as creeping and above-ground shoots rooted in nodes, is found in many perennial grasses. For example, common reed reproduces mainly by rhizomes; in extratropical countries it only rarely forms normally spaced grains. Some ephemeral grasses of the arid regions of Eurasia, including bulbous bluegrass (Poa bulbosa) and low catabrosella (Calabrosella humilis), have bulbous thickened bases of turf shoots. Later, during the dry season, their tufts are broken up by herbivores, and the bulbs are carried by the wind or on the feet of animals across the pasture.

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Asexual reproduction is no less common in cereals with the help of those parts or organs of the plant that are related to sexual reproduction. This includes vivipary, when a young plant develops not from a seed, but from spikelets modified into bulb-shaped buds. Complete or almost complete transformation of all spikelets of the panicle into such buds is found in a number of Arctic grasses from the genera Poa, fescue, pike, as well as in the bulbous bluegrass, widespread in the arid regions of Eurasia. In all cases, vivipary can be considered as an adaptation to more severe living conditions, although vivipary 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, are even more frequent, especially in the predominantly tropical millet and sorghum tribes. Of the extratropical grasses, there are many apomictic and semi-apomictic species in the genera Poa and Reed grass.

For cereals, highly specialized anemophilous plants, the daily rhythm of flowering and pollination is of particular importance. The exact coincidence of flowering of all individuals of a given species during any limited time of day significantly increases the chances cross pollination and is an important adaptation to increasingly advanced anemophily. Among extratropical grasses, 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 (evening is weaker), with round-the-clock flowering, with night flowering . The latter is found only in a few extratropical cereals. However, in hot and dry areas of the tropics, night flowering is known in many species, as it avoids overheating and rapid death of pollen during a hot day. Interestingly, in tropical night-blooming grasses, flowering shifts to early morning when moving outside the tropics, as the danger of pollen overheating decreases. Grasses that bloom at noon and afternoon flower during the hottest part of the day. At this time, pollen grains shrink and die relatively quickly, but such cereals are especially often characterized by the so-called explosive flowering, in which massive and simultaneous opening of flowers occurs in a very short time - no more than 3-5 minutes. With batch flowering, which is also characteristic of many cereals, not one, but several such explosions of flowering occur during the day. It has been shown that even very close species, for example, steppe fescue: Wallis (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 rhythm of flowering in cereals turned out to be a good species-specific systematic feature.

The unit of fruit distribution - the diaspora - in cereals is usually the anthecium: a caryopsis enclosed in floral scales with an adjacent segment of the spikelet axis. Much less often, bare (devoid of any scales) grains, whole spikelets, parts of a common inflorescence, the entire common inflorescence, or even the entire plant serve as diaspores. In the above-mentioned small sheathweed, the caryopses that strongly protrude from the flower scales fall out of them and are carried by water during fluctuations in river levels associated with floods, rains, changes in wind direction, etc. The psammophilous ephemeral sandpit of Palestine can serve as a rare example when caryopses falling from the spikelets carried by the wind. In the sporobolus (Sporobolus), which is widespread in the tropics, the sac-shaped grains, when wetted by rain or dew, quickly swell, burst, and the seeds squeezed out of them, surrounded by sticky mucus, hang from the spikelets, sticking to the fur of animals and the feathers of birds. Large grains of many bamboo plants falling from the spikelets are distributed mainly by water flows during tropical rainfalls, as well as with the help of birds. The berry-shaped grains of Melocanna begin to germinate on the mother plant, without a dormant period, then fall onto the moist soil with their sharp end down and continue their development on their own. They can also spread with the help of birds and animals that eat them.

Spreading by means of whole common inflorescences or their parts is also not very rare in cereals. The spike-shaped panicles of the whorled bristleweed (Setaria verticillata), very tenacious due to the presence of backward-pointing spines on the bristles surrounding the spikelets, often cling to animal fur or human clothing along with the stems. The ears of many species of Aegilops with large awns protruding to the side easily become entangled in animal fur, but can be transported over long distances and by the wind. Clusters of spikelets of barley (Hordeum jubatum), bearing very long and thin awns, can also be carried either by animals or by wind. In the latter case, numerous groups of spikelets can cling together, forming a spherical tumbleweed, carried by the wind over long distances, especially along highways. Many other cereals are spread by the wind like tumbleweeds, the latter being based on very large, widely and widely branched panicles. Examples of this kind are the Siberian bluegrass (Poa subfastigiata) or the Lower Volga zingeria Biebersteinii. In the littoral Asian and Australian genus Spinifex (Spinifex, Fig. 211, 3), the female common inflorescences, which have an almost spherical shape, fall off entirely, then roll along the sandy coast with the wind or float in the water and, having already lingered somewhere, gradually disintegrate. The method of distribution of the splayed snake (Cleistogenes squarrosa) - one of the characteristic plants of the steppes and deserts of Eurasia (Fig. 194, 2) is also very interesting. The stems of this species bend serpentinely when fruiting and break off at their base. Clutching with each other, they form tumbleweeds that are easily carried by the wind, and the grains gradually fall out not only from the apical panicle, but also from the axils of the stem leaves, where shortened branches with cleistogamous spikelets are located.

In cereals, the distribution of diaspores by wind and animals is almost equally represented, and in many cases, diaspores can spread in both ways (for example, in the feather grass Stipa capillata, which is common in the Eurasian steppes). Apparently, in many groups of cereals during evolution there was a transition from a predominantly zoochorous mode of distribution to a predominantly anemochoric one. Thus, in the genus reed grass, diaspores of more ancient, forest species (reed reed grass, etc.) have long, geniculately bent awns and a tuft of short, stiff hairs on the callus - an adaptation to zoochory, and diaspores of a relatively younger species of ground reed grass (Calamagrostis epigeios) are equipped with very a short awn and a tuft of very long (longer than the lemma) hairs on the callus, spreading exclusively anemochorously. Species of the feather grass, but more primitive genus Achnatherum, which is often combined with feather grass, also have small zoochorous diaspores, while highly specialized anemochoric species with very long (40 cm or more), doubly geniculate and pinnately hairy in the upper part of the awns are known among feather grasses. . A long and sharp callus with stiff hairs directed upwards allows feather grass diaspores to seem to be screwed into the soil. 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, either curls or unwinds, moving the flower scales with the grain deeper and deeper into the soil. In some feather grasses that can spread on animal fur, such as the feather grass, the diaspores can become embedded in their skin, causing serious damage to the animals.

An increase in the windage of diaspores in anemochoric cereals is especially often achieved due to long hairs, which can be located on the sides of the lower flower glume (in transylvanian pearl barley - Melica transsilvanica), on the highly elongated callus of the lower flower glume (in reed), on the segment of the spikelet axis above the base flower scales (in many species of reed grass), on highly elongated awns (in many feather grasses). In the cirrus (Stipagrostis pennata), common in the sandy deserts of Eurasia, the spine is divided into 3 pinnate branches, resembling a parachute in appearance. In many species of Chloris, the parachute device looks like a transverse row of long hairs in the upper part of the lower flower scales, and in the Persian nine-awned tree (Enneapogon persicus) - like a transverse row of 9 pinnately hairy awns. Thick but very light segments of ears of psammophilous genera - double scale (Parapholis) and single scale (Monerma) - are easily carried by the wind. The windage of diaspores consisting of a whole spikelet can increase due to winged glumes (in the canary plant - Phalaris) or due to their sac-like swelling (in Beckmannia - Beckmannia). In the shaker (Briza), the windage of the anthecia diaspores increases due to the greatly expanded and almost entirely membranous lower floral scales.

The adaptations of cereals to zoochory are no less diverse. Especially often, their diaspores-anthecia have geniculate, rough awns and stiff hairs on the callus, but in representatives of the genus Tragus and some other genera, hooked spines are located in rows on the back of the lower floral scales. In the herbaceous bamboo Leptaspis cochleata, the closed and swollen lower flower scales, which fall together with the grain, are covered with small spines hooked at the apex and are easily attached to the fur of animals (Fig. 197, 4). In the spiny bristlecone (Cenchrus), rather large spiny heads, consisting of several spikelets, enclosed in a wrapper of expanded and fused in the lower part of the setae - modified branches of the general inflorescence - spread exozoochorously (Fig. 202, 8-9). The fruiting spikelets of the tropical genus Lasiacis are spread by birds, which are attracted to the oil-rich, thickened spikelet scales. Diaspores of many species of pearl barley (Melica) have succulent appendages made of underdeveloped flower scales at the top of the spikelet axis and spread with the help of ants eating these appendages.

The diaspores of many aquatic and coastal grasses (for example, zisania, 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 unwinding of the awns. Currently, both the conscious and unconscious role of man in the spread of cereals has increased enormously. The ranges of cultivated species are expanding significantly, often together with their specific weeds. Many cereals from other continents are introduced into cultivation as forage plants and then go wild (for example, wheatgrass or New England wheatgrass, introduced from North America, became widespread in the USSR). Many types of cereals introduced into cultivation long ago have lost the method of distribution characteristic of their ancestors. Thus, in cultivated species of wheat, rye, and barley, the ears do not disintegrate into segments; Cultivated oats do not have articulations on the spikelet axis; Chumiza and mogar (Setaria italica) do not have articulations at the base of the spikelets, characteristic of wild representatives of this genus. Only in culture are cereals such as corn and bead grass known to be unable to reproduce without human help.

When a grain germinates, first of all, the embryonic root begins to grow, and then the embryonic bud, covered by the coleoptile. After the coleoptile emerges from the soil surface, the first leaf of the seedling emerges from it, which continues to rapidly lengthen and takes on a shape characteristic of this species. In cereals, there are 2 main types of seedlings: festucoid, when the first leaf of the seedling is narrow and directed almost vertically upward (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 panicoid tribes). In addition, there is an intermediate eragrostoid type, and recently two more types have been identified - bambusoid and orizoid, in which on the axis of the seedling the coleoptile is followed not by ordinary leaves, but by one or more cataphylls - scale-like leaves, and with bambusoid 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 versions of the cereal system were based mainly on easily noticeable features in the structure of common inflorescences and spikelets. For a long time, the system of the famous grain specialist E. Gakkel (1887) was generally accepted. This system was built on the principle of gradual complication in the structure of spikelets, from the sorghum and millet tribes, which usually have 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 20th century. Much new data has accumulated on the anatomy of leaves and stems, the structure of the embryo and seedlings, small details in the structure of flowers, and 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, floral films, stamens and stigma branches.

Important data for building a new system were also provided by the study of cereal chromosomes, associated with the rapid development of genetics. In the classic work of N.P. Avdulov, published in 1931, it was established that the size of chromosomes and their basic number (x) in the family of cereals are characteristics not only constant within the majority of genera, but also characteristic of larger divisions of this family. Relatively small chromosomes with a basic number of 6, 9 and 10 turned out to be characteristic primarily of tropical tribes of cereals (sorghum, millet, pigwort, etc.), and larger chromosomes with a basic number of 7 were found to be predominantly characteristic of extratropical tribes of bluegrass, oats, wheat and others. 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: the reed (Phragmitiformis) with more ancient tribes having small chromosomes, and the fescue (Festuciformis) with the majority of extratropical grass tribes having large chromosomes, usually in a multiple of 7.

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

Forest herbaceous plants Wikipedia - ? Zingeria Bieberstein Scientific classification Kingdom: Plants Division: Flowering plants ... Wikipedia

Angiosperms (Magnoliophyta, or Angiospermae), a division of higher plants that have flowers. There are over 400 families, more than 12,000 genera and probably at least 235,000 species. According to the number of species of C. r. significantly superior to all others... Great Soviet Encyclopedia

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

Description of cereal crops and their importance for humans

The fruit of cereal plants is a monocotyledonous grain seed fused with a shell. The leaves are long, with parallel veins, narrow, two rows. The stem is hollow and thin. Usually long. Inflorescences are paniculate, spikelet or racemose.

The importance of cereal plants is great; it was from them, even in ancient times, that people learned to make bread and porridge. At first, bluegrass (the second name of the cereal family) was not given special 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 today's loaves and long loaves did not yet exist. Later, cereals began to have not only nutritional, but also medical significance due to the beneficial substances they contain. In addition to cultivated plants that benefit humans, there are weeds that are harmful to agriculture, as well as perennial cereal grasses that are completely harmless.

Cultivated cereals

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

Search suitable plants, every time go and find out: where they grow and in what quantity. Then take the seeds, take them home, and so on in a circle. After all, you can start growing cereal plants not far from your own home. Plant the fruits, water them and wait for them to sprout, grow into plants and ripen.

New fruits were collected, some were left for grinding, and some were left for the next sowing. This is how agriculture developed. New varieties of cereals were developed, which should be resistant to droughts and other negative influences. Breeders took into account the flower formula of cereals in order to predict the genetic structure of new plants and create a similar formula.

The modified individuals were subjected to thorough 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, weed and herbaceous plants

Bluegrass is divided into three main categories: grains, weeds and grasses. Some species are used for decoration.

The lists do not represent all representatives, but several well-known cultivated, weed and herbaceous species. In fact, there are many more of them.

Cereals:

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

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

• feather grass;
• grate;

All cereal grasses that grow freely in meadows should not be called weeds. They are the main food for livestock and poultry.

Photos and names of cereal grains

Cultivated cereals are specially grown for use as a food product. In my food I use whole and crushed grains, flour and baked goods made from it.

Millet

Millet is a plant that tolerates heat and drought well. Common millet is valuable; it is from its seeds that millet is obtained. Homeland - Southeast Asia. It is grown everywhere, including on saline soils. High acidity is the only weakness of millet; it cannot tolerate it and dies. The grains are used to prepare porridges, soups, and also as feed for poultry.

Oats

An annual plant that is widely used in agriculture. It is resistant to negative environmental conditions and can be grown on lands where it is quite cold. Originally from some provinces of Eastern China and Mongolia. Previously, it was perceived by farmers as a weed, but its feeding properties refuted this opinion. Later they learned to make various pastries from it, and the Germans brewed so-called white beer. It can be filmy or bare-grained. 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. Residents of the Middle East were among the first to notice its benefits. Bread made from barley flour is heavier and coarser than wheat, but it is still considered a healthier product. The plant is single-flowered and self-pollinating. Nowadays, barley is grown for both feed and food needs. Beer made from barley is also common among connoisseurs of this product.

Corn

Also called maize or sweet corn. 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 entire family in its large cob with yellow seeds. Country of origin: Mexico.

It ranks second in sales after wheat. It is used to make corn starch, canned food and even medicines.

Rice

An annual herbaceous plant. Requires special attention, the plant is capricious and needs a lot of moisture. It is grown in Asian countries, but some types of rice are grown in African countries. Rice fields are made so that they can be flooded with water (protection from sunlight) while the plant matures, but then drained for harvest. Cereals and starch are produced from grains. If the grains are germ, then they are perfect for making rice oil.

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

Rye

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

Wheat

This grain crop is in first place in cultivation and sale. High-quality bread 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 areas belonging to the tropical zone. Includes about ten species.

Many people believe that yellow spikelets with long whiskers 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 weed cereals. Many of these plants are used as animal feed.

Creeping wheatgrass

Easily displaces cultivated plants. Very tenacious, capable of drawing juices from the ground that other species need. The roots are powerful, more powerful than those of cultivated representatives. Does very well in moist, fertile soil.

Chicken millet

Chicken millet or barnyard grass. 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

Crabgrass, especially crabgrass, has the same ability to survive as other weeds. Can exist on acidic soils. It has a lot of seeds in its paniculate spikelets. For them to germinate, only two degrees of heat is enough.

Rye fire

Can easily be confused with rye, but survival rate is slightly higher. Drought resistant. Lives in rye fields. When its seeds are mixed during collection with the seeds of a cultivated relative, the quality of the harvest decreases.

Gumai

It also has another name - Aleppo sorghum. It is one of the most dangerous plants and poses a serious threat to cereal crops. It survives droughts well, but despite this, sorghum is very demanding of moist and fertile soil. It has a powerful rhizome for constant consumption of nutrients.

Chaff multicolor

Affects legumes and cereals. The chaff is spread everywhere. Survives well in adverse conditions. The plant is strong and can reach one meter in height. Prefers nitrogenous soils.

Bluegrass annual

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

Photos and names of cereal herbs

Cereal herbs can become a decoration for our summer cottages if we 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 sun rays and moderate moisture. Excellent as food for cattle and.

Perlovnik

So called because its seeds are very similar to pearl barley. The plant is a perennial, growing in forests and sometimes in steppes. Often found along the shores of lakes and swamps. Includes several varieties.

Feather grass

Lives in European steppes and meadows. It has a long thin spikelet that from a distance resembles a light gray thread. Very suitable as feed for farm animals. It needs sunny, neutral soils. Pollinates 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. The spikelets are paniculate, large, dark purple in color. It grows in the European part of the continent, in sunny areas or surfaces with moderate shade. Often used as an ornamental plant.