A genus of large perennial grasses of the cereal family. Introduction to cereals. Nutritional value of cereal grains

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

Description of cereal crops and their importance to humans

The fruit of cereal plants is a monocotyledonous grain seed, fused with the shell. The leaves are long, with parallel venation, narrow, two rows. Stem hollow, thin. Usually long. Inflorescences paniculate, spicate or racemose.

The value of cereal plants is great, it was from them, back in ancient times, people learned to make bread and cereals. At first, bluegrass (the second name of the cereal family) was not given 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 dough, since today's loaves and loaves did not yet exist. Later, cereals began to have not only nutritional, but also medical significance due to the contained nutrients. 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, it became clear to people that not all cereals are edible and suitable for cooking. They searched only for those from whose grains delicious food was obtained. That is, cultural cereals were needed. Also, the person realized that it is not necessary to collect something somewhere.

Look for suitable plants, walk every 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 growing cereal plants near your own home. Plant the fruits, water and wait until they sprout, plants grow from them and ripen.

New fruits were harvested, some were left to grind, 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 impacts. Breeders took into account the formula of the flower of cereals, in order to predict the genetic structure of new plants, to make a similar formula.

Changed individuals were subjected to thorough research. The main goal of breeders is the creation of perfect varieties. These plants must be absolutely resistant to drought, weeds and other adverse effects. Each variety has its own name.

List of cultivated, weedy and herbaceous plants

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

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

Cereals:

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

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

• feather grass;
• grate;

You should not 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 very well. Millet is of value, it is from its seeds that millet is extracted. Homeland - Southeast Asia. It is grown everywhere, including on saline soils. Increased acidity is the only weakness of millet, it cannot stand it and dies. The grains are used to make cereals, soups, and also as poultry feed.

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 is 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. One of the first to notice its benefits was the inhabitants of the Middle East. Bread made from barley flour is heavier, rougher than wheat, but is considered a more useful product even now. The plant is single-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 cob 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 herbaceous plant. Requires special attention, the plant is capricious, 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 the sun's rays) while the plant matures, but then drained to harvest. Groats and starch are produced from grains. If the grains are germinal, then they are great for making rice oil.

Produce alcohol, medicines from rice. Rice straw is used to make paper, and fodder bran is made from the husk.

Rye

Nowadays, winter rye is mainly used for sowing, as 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. Rye easily suppresses weed grass, 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 the first place in cultivation and sale. High-grade bread is baked from wheat flour, confectionery and pasta are produced. Wheat is also used in the production of beer and other spirits. It is grown on almost all lands, except for territories belonging to the tropical zone. Includes about ten species.

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

Photos and names of weeds

With weed cereals, a person has to fight. Many of these plants are used as animal feed.

Creeping wheatgrass

Easily displaces cultivated plants. Very tenacious, able to draw juices from the ground that other species need. The roots are powerful, more powerful than those of cultural representatives. Feels very good on moist fertile soil.

chicken millet

Chicken millet or barnyard. It bears such a 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

Rosichka, especially the blood-red one, 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 are enough.

Rye bonfire

It can be easily confused with rye, but the survival rate is slightly higher. Drought tolerant. Lives in rye fields. When its seeds are mixed at harvest with the seeds of a cultivated relative, the quality of the crop is reduced.

Gumay

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

Chaff multicolor

Attacks legumes and cereals. The weed is spread all over the place. Excellent survival in adverse conditions. The plant is strong, can reach one meter in height. Prefers nitrogenous soils.

bluegrass annual

Another representative of cereal weeds that harm agriculture. It grows in the fields, mainly where cereals 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

Cereal herbs can become a decoration of our suburban areas, 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. Likes sunshine and moderate moisture. Excellent as food for cattle and.

Perlovnik

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

Feather grass

It lives in the European steppes, in meadows. It has a long thin spikelet, from a distance resembling a light gray thread. Very well suited as feed for farm animals. He needs sunny, neutral soils. It pollinates itself.

Kolosnyak

It 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. Leaf color is blue-green.

Moliniya

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 paniculate, large, dark purple. It grows in the European part of the mainland, in sunny areas or surfaces with moderate shade. Often used as an ornamental plant.

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 that they play in the composition of herbaceous vegetation groups - meadows, steppes, prairies and pampas, as well as savannahs. The main food plants of mankind belong to the cereals - soft wheat (Triticum aestivum), sowing rice (Oryza sativa) and corn (Zea mays), as well as many other crops that supply us with such necessary products as flour and cereals. Perhaps no less important is the use of cereals as fodder plants for domestic animals. The economic significance 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 land 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 the flowering plants that rise the highest in the mountains, cereals also occupy one of the first places.

For cereals, the relative uniformity of their distribution on Earth is characteristic. 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 number of species. Among the cereals there are relatively few narrow endemics, but they are given for Australia 632, for India - 143, for Madagascar - 106, for the Cape region - 102. In the USSR, endemic cereals are rich in Central Asia (about 80) and the Caucasus (about 60 species). Cereals are usually easy to recognize by their appearance. They usually have articulated stems with well-developed nodes and two-row arranged alternate 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 grasses are herbaceous plants, however, in many representatives of the bamboo subfamily (Bambusoideae), the stems are highly woody, highly branched in the upper part, with numerous nodes, retaining, however, the structure typical of grasses. In South American species of bamboo (Bambusa), they are up to 30 m high and 20 cm in diameter. In South Asian giant dendrocalamus (Dendrocalamus giganteus), a 40 m high stem is not inferior in growth to many trees. Among the bamboos, climbing or climbing, sometimes thorny vine-like forms are also known (for example, the Asian Dinochloa -- Dinochloa). The life forms of herbaceous cereals are also quite diverse, although outwardly they seem to look the same. Among the grasses there are many annuals, but perennial species predominate, which can be turfy or have long creeping rhizomes.

Like most other monocotyledons, cereals are characterized by a fibrous root system, which is formed as a result of 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, secondary adventitious roots begin to develop from the lower contiguous nodes of the seedling, which usually form the root system of an adult plant. In grasses 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, the branching of the shoots is carried out 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. 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 upwards inside the sheath of its covering sheet. With this method of shoot formation, very dense turfs are formed, as in many species of feather grass (Stipa) or in fescue-fescue (Festuca valesiaca). The bud of the extravaginal shoot begins to grow horizontally and pierces the sheath of the covering leaf with its tip (Fig. 192, 2). This method of shoot formation is especially characteristic of species with long creeping underground shoots-rhizomes, for example, creeping couch grass (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 tufts 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 forms shoots of both types (Fig. 192).

Branching of the 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 - Aeluropus). Much more often it can be seen in the cereals of the tropics, and their lateral shoots usually end in inflorescences. Tufts of such cereals often resemble bouquets or brooms in appearance. Especially strongly branched in the upper part of the stems are characteristic of large bamboos, and they even have a whorled arrangement of lateral branches, for example, in some Central American species of cheskveya - Chusquea (Fig. 193, 5). Many cereals with aboveground shoots creeping and rooting at the nodes, for example, bison grass (Buchloe 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 Muhlenbergia torreyi (Muhlenbergia torreyi) and some other species, such clones grow along the periphery and die in the middle, forming a kind of "witch's rings" in some species 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 may exist for one or several years, and then proceed to flowering. Elongated reproductive shoots are formed from them after the appearance of the rudiment of a common inflorescence due to the rapid intercalated growth of internodes. At the same time, each segment of the cereal shoot grows independently under the protection of the leaf sheath, having its own intercalated meristem zone. The core in growing internodes usually dies off quickly, and they become hollow, but in many cereals of tropical origin (for example, corn), the core is not only preserved throughout the stem, but also has scattered vascular bundles. Core-filled internodes are also present in many liana-like bamboos. Sometimes, during the transition to an elongated reproductive shoot, only the uppermost internode located under the inflorescence is elongated, for example, in the blue lightning (Molinia coerulea).

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

Signs of the anatomical structure of the stem are used in the systematics 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 are characteristic (outer from smaller bundles), and for predominantly tropical - panicoid (from Panicum - millet) - internodes with a narrow cavity or without it and with the arrangement of conductive 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 found on rhizomes, and often also at the base of above-ground shoots. In many bamboos, deciduous scale-like leaves without blades or with very small blades are often located almost along the entire length of the main shoot. The scales are primarily protective and usually follow the very first leaf-like organ of the shoot, a preleaf that is always scale-like and usually two-keeled.

In ordinary, assimilating leaves, the sheath is formed by the base of the leaf that has grown in the form of a case covering the stem and serves as protection for the growing internode. Sheaths of cereals can be either split to the base (for example, in the predominantly tropical tribes of millet - Paniceae and sorghum - Andropogoneae), and fused edges into a tube (in the tribes of brome - Bromeae and barley - Meliceae). In some species of steppes and semi-deserts (for example, in bulbous bluegrass - Roa bulbosa, Fig. 195, 4), the leaf sheaths of vegetative shoots become a storage organ, and the shoot as a whole resembles an onion. In many grasses, dead sheaths of the lower leaves protect the bases of the shoots from excessive evaporation or overheating. When the vascular bundles of the sheaths are interconnected by strong anastomoses, a reticulate-fibrous cap is formed at the base of the shoots, which is characteristic, for example, of the coastal brome (Bromopsis riparia), which is common in the steppes of the European part of the USSR.

A membranous or thin-skinned outgrowth located at the base of the leaf blade and directed vertically upwards - 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 grasses (Eragrostoideae), it is modified into a series of densely arranged hairs. In most species of the widespread genus Barnyard (Echinochloa) and in the North American genus Neostapfia (Neostapfia), the tongue is completely absent and the vagina passes into the plate without a clearly defined border between them. On the contrary, very long (2-4 cm) tongues are found in the Mexican caudate Muhlenbergia (Muhlenbergia macroura). At the top of the vagina on the sides: from the tongue, some cereals (especially bamboo) have 2 lanceolate, often crescent-curved outgrowths called ears.

In the vast majority of cereals, leaf blades have 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 (Arthraxon) and in a number of other, mainly tropical, genera, they are lanceolate-ovate, and in 2 African genera - phyllorachis (Phyllorachis) and umbertochloa (Umbertochloa) - even swept at the base (Fig. 196, 10) . In the bamboo subfamily, 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 heart-shaped and connected to the sheaths by a petiole, up to 25 cm long (Fig. 197, 7). Very long petioles also have leaves of another American genus - farus (Pharus), which have another feature that is not characteristic of other cereals - pinnate venation of the plates. In most bamboos, as well as in some broad-leaved grasses from other subfamilies, 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 of coastal monantochloe (Monanthochloe littoralis), the plates of densely arranged leaves rarely exceed 1 cm in length, while in the South American bamboo high neurolepis (Neurolepis elata) they are up to 5 m long and 0.6 m wide. Very narrow, bristle-like folded or folded leaf blades have many types of feather grass, fescue: and other, usually xerophilous cereals. In the African bristle-leaved miscanthidium (Miscanthidium teretifolium), very narrow plates are represented by almost only the midrib.

The anatomical structure of the leaf blades as a systematic feature is of even greater value in cereals than the anatomical structure of the stems, and is usually characteristic of subfamilies and tribes. Currently, 6 main types of the anatomical structure of leaf blades are distinguished: festucoid, bambusoid (from Bambusa - bamboo), arundinoid (from Arundo - arundo), panicoid, aristidoid (from Aristida - triostennitsa) and chloride or eragrostoid (from Chloris - - chloris and Eragrostis - field grass). The festucoid type (mainly extratropical tribes of cereals) is characterized by a disordered arrangement of chlorenchyma, a well-developed internal (sclerenchyma) and an external (parenchyma) lining of vascular bundles relatively weakly delimited from chlorenchyma (Fig. 198, 1). The bambusoid type, characteristic of the bamboo subfamily, is in many respects similar to the festucoid type, but differs in chlorenchyma, consisting of peculiar lobed cells arranged in rows parallel to the epidermis, as well as in the outer lining of vascular bundles more isolated 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 lining is well developed and consists of large cells without chloroplasts, chlorenchyma cells are located densely and partly radially around the bundles. For the rest of the types (mainly tropical subfamilies of the field grass and millet), the radial (or crown) arrangement of chlorenchyma around the vascular bundles is characteristic, and in the chloride type the inner (sclerenchyma) lining of the bundles is well developed, while 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 outer (parenchyma) lining of the conducting bundles, which is well separated from it (the so-called Kranz syndrome, from German kranz - a wreath), primarily a special method of photosynthesis -- C4 carbon dioxide fixation pathway, or cooperative photosynthesis, based on the cooperation of chlorenchyma cells and parenchymal linings that perform different functions. Compared to conventional C3 by carbon dioxide fixation, this pathway 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 on the example of the species of field grass (Eragrostis), setaria (Setaria) and skrytnik (Crypsis) in the southern regions of the USSR that have it: the maximum development of these species occurs in the driest season here - July - August, when most cereals ends the growing season.

According to the structure of the leaf epidermis, especially silicified cells and hairs, the above types of leaf anatomical structure also differ well. 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, while at the ends, on the contrary, they are expanded with thin walls. This structure allows you to adjust the width of the stomatal gap by expanding or narrowing the thin-walled parts of 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 pinnately hairy 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 located scales with flowers and their axils are called the lower floral scales. Both are homologous to leaf sheaths, with the lower lemmas often bearing awned appendages that are usually considered homologous to leaf blades. Some bamboos 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 cereals, one (in the chaff - Lolium) or both (in the sheath flower - Coleanthus, Fig. 201, 6) glumes can be completely reduced. True glumes are by origin upper leaves, and not bracts (bractae), like the lower lemmas. However, in many cases (especially in the millet tribe) the reduction of flowers in the axils of the lowest lemmas makes the latter very similar to additional glumes. The spikelet and lower glumes of the most primitive bamboos, like the leaf sheaths, have 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 the spikelets can vary from very large and indefinite (for example, in the two spikelets - Trachynia - up to 30 flowers, Fig. 201, 14, 15) to constantly one (in the reed or foxtail) or two (in the calamus - Aira ). Very primitive many-flowered spikelets with a strongly elongated and often branched axis have Chinese bamboo long spikelet (Pleioblastus dolichanthus). 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 (Melocanna). In his axils of the spaced lower lemmas, not 1, but 2 or 3 flowers are placed on the lateral axes provided with bracts. It is quite probable that the evolution of common inflorescences in cereals proceeded from such common inflorescences not yet differentiated into spikelets to inflorescences with well-separated spikelets, first many-flowered, and then single-flowered.

The axis of the many-flowered spikelet is usually articulated under each lower lemma and breaks into segments at fruit. The base of the lower lemma, 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, which includes one flower, lemmas, and the segment of the spikelet axis adjacent to them, is often called an anthecium. In uniflorous spikelets, there may be no articulation under the lower lemma, and then the spikelets fall off in full at the fruit.

Common inflorescences of cereals usually have the form of a panicle, often very dense and spike-shaped, brush or spike. Only small specimens of two spikelets (Fig. 201, 14), species of fire (Bromus) and some other cereals carry 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 Abyssinian oxytenantera (Ohutenanthera abyssinica, Fig. 193, 1) or in the Mediterranean ephemera of the blackberry (Echinaria, Fig. 201, 11), and sandbox (Ammochloa, Fig. 201, 7 ). In thorny bristles (Cenchrus), the common inflorescence consists of several prickly heads (Fig. 202, 8, 9). The result of a higher specialization of common inflorescences is an ordered arrangement of spikelets one at a time or in groups of 2-3 on one side of the flattened axes of spicate branches, which, in turn, can be arranged alternately or palmately (as in the pigtail - Cynodon, Fig. 194 , four). With this arrangement of spikelets, which is especially characteristic of the tribes of millet, sorghum, and porcini, some of the spikelets on spike-like twigs (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 stem with a barely noticeable rudiment of a spikelet remains from the spikelet on the stem. Single-sex spikelets are not so rare in cereals at all. In this case, spikelets with male and spikelets with female flowers can be located within the same inflorescence (in Zizania - Zizania, Fig. 196, 7, 9), on different inflorescences of the same plant (in corn) or on different plants (in pampas grass, or Sello's cortaderia - Cortaderia selloana, tab. 45, 3, 4).

In the axils of the lower lemmas, on the side of the spikelet axis, there is another scale, usually having 2 keels and a more or less noticeable notch at the top. 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 perianth circle, but at present, most authors consider it to be a preleaf of a strongly shortened shoot bearing a flower located in the axil of the lower lemma. In some genera of grasses (for example, in foxtail), the upper lemma can be completely reduced, and in the very original American grassy bamboo streptochaete (Streptochaeta), it is split almost to the base.

Above the upper lemma, on the axis of the flower of the vast majority of cereals, there are 2 small colorless scales, called lemmas or lodiculae. As to their nature, there is still no consensus. 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 the 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 two ventral ones, usually closely adjacent and often connected to each other at the base.

The structure of the lodicula is considered an important systematic feature characteristic of entire tribes of cereals (Fig. 203). Many bamboos have large scaly lodicules with vascular bundles, where they have a predominantly protective function. In the majority of other grasses, the lodicules look like small whole or bilobed scales, devoid or almost devoid of vascular bundles and strongly thickened in the lower half. It is assumed that such lodicula accumulate nutrients for the development of the ovary, regulate the water regime of the flower and contribute to the spreading of the lemmas during flowering. Usually, 4 main types of lodicula structure are distinguished: bambusoid, festucoid, panicoid and chlorideoid, corresponding to the main types of leaf anatomy. Often a melikoid type (from Melica - barley), characteristic of the barley tribe (Meliceae), is also distinguished: very short (as if chopped off in the upper part) lodicules stick together with each other with their front edges. 3 large, spirally arranged lodiculae are present in the streptochaete mentioned above, but not all authors take them for lodicules. Finally, in many genera (including foxtail and sheathflower) the lodiculae 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 is reduced to 2 (in the fragrant spikelet - Anthoxanthum) or to 1 (in cinna - Cinna). The number and structure of stamens in the bamboo subfamily varies greatly. So, in the South Asian genus Ochlandra (Ochlandra), the filaments of stamens branch many times, as a result of which there can be up to 50-120 stamens in one flower. In the genera Gigantochloa (Gigantochloa) and Oxytenanthera (Oxytenanthera), the filaments of 6 stamens fuse into a rather long tube surrounding the ovary (Fig. 193, 3). The Brazilian anomochloa has 4 stamens. The filaments of stamens of cereals are able to quickly lengthen 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 fused with their edges, and the fruit of cereals - the grain - is a kind of paracarp 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 primary 3-membered apocarpous gynoecium. The ovary is always unilocular with a single ovule, which can be orthotropic to hemitropic (rarely campylotropic) with a downward micropyle. The integument is usually double, but in the otherwise anomalous genus Melokanna it is simple. Usually the ovary passes at the apex into 2 pinnately hairy stigma branches, but many bamboos may have 3. The bare bases of the stigma branches vary greatly in length in different tribes. They are especially long in the predominantly tropical millet tribe, which is apparently associated with more closely packed lemmas. In some grasses, the stigma branches may be fused with each other along the entire or almost the entire length. So, in corn, only the upper parts of very long stigma branches are free, while in the white-bearded (Nardus) the ovary passes at the top into a completely whole filiform stigma, covered not with hairs, like in other cereals, but with short papillae. In bamboo - streptogyna (Streptogyna), the stigma branches covered with spines after flowering become very rigid and serve to spread the grains (Fig. 204, 4).

The indehiscent dry one-seeded fruit of cereals, called a caryopsis, has a thin pericarp, usually so tightly adjacent to the seed coat that it seems to be fused with it. Often, when a caryopsis ripens, its pericarp sticks together with lemmas tightly adjacent to it. In sporobolus (Sporobolus), the pericarp remains separated from the seed, and the caryopses in this case are 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 grain has a scar, or hilum, usually darker in color compared to the rest of the grain and having a shape from almost round (in bluegrass) to linear and almost equal in the length of the entire grain (in wheat). The hilum is the site of attachment of the ovule to the stalk (funicular), and its shape is determined by the orientation of the ovule.

The most original in their structure are the grains of some bamboos, which can be berry-shaped with a thick fleshy pericarp or nut-shaped with a fairly thick and very hard in consistency pericarp, separated from the seed peel. In the melocanna, common in Southeast Asia, the berry-like caryopses have an obverse pear-shaped shape 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 a mature grain, only a dry film remains from it between the pericarp and the strongly overgrown shield.

In all other cereals, most of the mature caryopsis is endosperm, and the ratio between the size of the endosperm and the embryo is of significant systematic importance. So, for festucoid cereals, the relatively small size of the embryo is characteristic, and for panicoid cereals, they are larger in comparison with the endosperm. Usually, the endosperm of mature grains is firm in consistency, but can be looser - farinaceous when there are few proteins in it, or denser - glassy with a relatively high content of proteins. It can be noted that the endosperm of cereal grains contains prolamins, 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. Such an endosperm is distinguished by its extraordinary resistance to drying, retaining a semi-liquid consistency even in caryopses stored in herbariums for over 50 years.

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 lat. Triticum - wheat); in millet and other panicoid cereals, they are also simple, but vary less in size and have a faceted surface, while in fescue and many other festucoid cereals, starch grains are complex, consisting of smaller granules (Fig. 205).

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The germ 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 shield. Outside of it and closer to its upper part is an embryonic kidney, dressed in a two-keeled sheath-shaped leaf - a coleoptile. Many cereals have a small fold-like outgrowth against the shield on the outside of the kidney - the epiblast. In the lower part of the embryo there is an embryonic root, dressed in a root sheath, or coloriosis. The nature of all these parts of the embryo is the subject of debate. The scutellum is usually taken as a single, modified cotyledon, and the coleoptile as its outgrowth or as the first leaf of a bud. The epiblast, when present, is taken either as a fold-like outgrowth of the coleorhiza, or as a rudiment of the second cotyledon. Coleorhiza, according to some authors, is the lower part of the hypocotyl knee - the hypocotyl, in which the germinal root is laid, according to others - the modified main root of the embryo.

Features of the structure of the germ of cereals are of great systematic importance. Based on the presence or absence of an epiblast or gap between the lower part of the scutellum and the coloriorhiza, 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, 3 main types of embryo structure were established on the transverse 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 the representatives of this family to a wide variety of environmental conditions, which allowed them to spread throughout the land of the globe, up to the very extreme limits of the existence of flowering plants. Grasses are found in almost all plant groups, although they are most characteristic of meadows, steppes and savannas of various types. There are species that live on moving sands (selin - Stipagrostis, sand-loving - Ammophila, etc.) and salt marshes (especially the coastal - Aeluropus and the aquifer - Puccinellia), both coastal and inland. Some species of tides grow in a strip flooded by tides, and one arctic species confined to such habitats, creeping abscissus (P. phryganodes), often does not bloom, propagating with the help of vegetative shoots creeping and rooting at the nodes. The lowland and upland meadows of Eurasia are especially characterized by numerous species of the genera bluegrass, fescue, bent grass (Agrostis), reed grass (Calamagrostis), foxtail, rump (Bromopsis), timothy grass (Phleum), shaggy (Briza), etc. In the steppe zone and in upland in the steppes of Eurasia, feather grass, fescue fescue, thin-legged (Koeleria), wheatgrass (Agropyron), sheep (Helictotrichon), and in more southern regions - bearded vulture (Bothriochloa) acquire leading importance. In the prairies of North America, chlorideoid grasses come to the fore: butelua (Bouteloua), chloris (Chloris), bison grass (Buchloe dactyloides), etc. ). In the pampas of South America, pampas grass species play an important role. - cortaderia (Cortaderia), forming giant turfs (Table 45, 3, 4).

In forests, the role of grasses in the vegetation cover is, of course, less significant, but here, too, some species of this family can dominate in the herbaceous layer. So, in the spruce forests of Eurasia, reed reed grass (Calamagrostis arundinacea) often grows in abundance, and in oak forests - forest bluegrass (Roa nemoralis), dog elimus (Elymus caninus), giant fescue (Festuca gigantea) and other species. In contrast to the steppe grasses, which are usually densely tufted and have very narrow, lengthwise folded leaf blades, forest grasses have less dense tufts, wider and less rigid leaf blades. Of the two species of barley common in deciduous and mixed forests of Eurasia, the more northern - drooping barley (Melica nutans) belongs to loose turf grasses, and the more southern and therefore more xerophilic colored barley (M. picta) belongs to dense tufts. Among tropical and subtropical forest cereals, many have recumbent or climbing densely leafy shoots and very wide, lanceolate or lanceolate-ovate leaf blades, resembling tradescantia species that are widespread in greenhouse and room culture in appearance. Representatives of the genus Oplismenus, for example, have such a life form, one of the species of which, the curly-leaved ostyanka (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 bamboos usually form large thickets along the banks of water bodies, along streams descending from mountains, on the edges and clearings of tropical forests. Many herbaceous bamboos grow under the canopy of the tropical rainforest and tolerate considerable shade. Above-ground shoots of tree-like bamboos are often considered homologous to the rhizomes of other cereals. They are characterized by extremely rapid growth and carry scale-like 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 a separation 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 bamboos with more or less woody stems, two main life forms are distinguished, confined to different climatic conditions (Fig. 207). Most tropical bamboos, which are naturally controlled by moisture levels (usually the onset of the rainy season), have stems relatively close together, forming a kind of loose bush. Such bamboos have so-called pachymorphic (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 bamboos 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 usually have a relatively small overall size, although some types of leaf-grate are up to 10 or even 15 m high. Leptomorphic rhizomes also have the only wild-growing bamboo genus in the USSR - saza (Sasa), which forms very dense and impenetrable thickets on the slopes of mountains in the south Sakhalin and the Kuril Islands.

Herbaceous bamboos, like grasses of other subfamilies, bloom annually, but bamboos with woody stems tend to bloom once every 30-120 years and usually die thereafter, being obligate or facultative monocarpics. In 1969, almost all over Japan, there was a mass and simultaneous flowering of the bamboo-like leaf grate (Phyllostachys bambusoides), which is very widely cultivated there for technical purposes. This was a real disaster for those who grew it, since a significant part of the plantations died after flowering. Almost all of the Japanese leaf-flower 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 cereals, especially tropical ones, there are gigantic forms that are not inferior in height to many bamboo ones. Such, for example, are 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 pure thickets along the banks of water bodies, and often in the water. Common reed is almost cosmopolitan and is widely distributed 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 marshy forests, on mountain slopes with an inflow of groundwater and on salt marshes, forming in extreme conditions of existence a peculiar form with creeping along the ground and only vegetative shoots. However, even in normally developed flowering cane clones, grains are not always formed and in small quantities, which, apparently, is associated with the great antiquity of this species. Another giant, up to 3 m high, grass is pampas grass, or cortaderia, one of the species of which is introduced to the Mediterranean countries, forms very dense turfs with intravaginal shoots (Table 45, 3, 4). Its narrow and very hard leaf blades bear large spines along the edges and midrib, resembling in this respect the leaves of the aquatic plant teloresa (Stratiotes).

The formation of dense turfs 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 densely tufted grasses (for example, chia shiny, many types of feather grass, etc.). On the contrary, long-rhizome include many meadow grasses, especially those living on loose, slightly sodden soils, for example, creeping couch grass and awnless brome (Bromopsis inermis), often growing in abundance in the meadows of river floodplains, as well as some coastal species, like reeds, forming dense thickets, for example, species of manna (Glyceria), reedweed (Scolochloa), broad-leaved 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 spinous hygrorhiza (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 very interesting group of life forms in many respects 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 hibernate, continuing their development in spring. In such a widely cultivated bread plant as wheat, there are not only many spring and winter varieties, but also varieties of "two-handled", which can be spring or winter, depending on the sowing time. Annual grasses can be divided into 2 groups also according to their origin. One of these groups is spring ephemera. Quickly ending their life cycle during spring - early summer, they play a very significant role in the composition of ephemeral vegetation in the arid and subarid regions of Eurasia, Africa and North America. It is very important that such valuable food and fodder crops as wheat, rye, oats and barley originate from the ancient Mediterranean ephemera.

Another large group of annual grasses belongs to the predominantly tropical tribes of millet, sorghum, hogweed, triostrennitsa, etc., although some species of this group (for example, species of bristle, field grass, rosichki - Digitaria and barnyard) 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 the 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. So, in the two spikelet deukolosy (Trachynia distachya), the common inflorescence consists of only 1-2 large multi-flowered spikelets (Fig. 201, 14); in the capitate blackberry (Echinaria capitata), the spikelets are collected in an almost spherical apical head, prickly with fruits (Fig. 201, 11); in the eastern rhizocephalus (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 Apsheron Peninsula, often almost the entire plant is covered with sand, from which only the tops of the leaves of the rosette are visible. Biologically very interesting is the late ephemeral small sheath flower (Coleanthus subtilis), which lives on the coastal shallows of more or less large rivers. It develops very rapidly after emerging from the shallows, reaching full development in September - early October. This is a small plant, 3-5 cm high, with lying or ascending shoots and very small single-flowered spikelets without spikelet scales, collected in umbellate bundles (Fig. 201, 5). In years when the shallows remain flooded, this species does not develop at all and may generally 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 along the Amur.

High specialization of flowers of cereals for pollination with the help of wind has already been noted above. However, the accidental transfer of grass pollen by insects, even in extratropical grasses, cannot be considered completely excluded. It has recently been found that herbaceous bamboos from the genera Olira (Olyra) and pariana (Pariana), growing under the canopy of trees in tropical rainforests, where air movement is extremely low, as a rule, are pollinated by insects, mainly flies and beetles, although such a secondary transition to entomophily is not yet associated with any special adaptations.

The great 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 facultative self-pollinating species. Such, for example, are all types of wheat and Aegilops (Aegilops), as well as most types of fire (Bromus). Some cereals, in addition to ordinary spikelets with chasmogamous flowers, also develop spikelets with cleistogamous flowers, pollinated with closed scales. The formation of these spikelets guarantees the possibility of seed propagation under adverse weather conditions or when the plant is excessively bitten by herbivores. Thus, in the widespread coastal grass Leersia oryzoides and the North American secretive-flowered sporobolus (Sporobolus cryptandrus), in unfavorable years, only spikelets with cleistogamous flowers are formed and the panicles do not protrude from the expanded sheath of the upper leaf. In the panicles of many feather grasses of the flora of the USSR, only cleistogamous flowers form in dry years, while in cooler and more humid weather, all or almost all flowers of the panicle bloom openly. Many arctic grasses also flower mostly cleistogamously in particularly cold weather.

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 nine-flowered northern (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 breed even in conditions of increased pasture grazing, when every year all the turfs are bitten almost to the ground by cattle. At the same time, grazing cattle breaks the turf with their feet and spreads, together with the lumps of earth that have adhered to them, the grains of the nine-horse. An even higher specialization in this regard is noted in the North American amphicarpum (Amphicarpum). Its single spikelets with cleistogamous flowers are formed on the tops of creeping underground shoots under the soil surface (Fig. 202, 3).

Same-sex 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 bison (Hierochloe) of 3 spikelet flowers, the upper one is bisexual, and the 2 lower ones 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 sorghum tribe, the arrangement of spikelets on spike-shaped branches of the common inflorescence in groups of 2 is very characteristic: one is sessile with a bisexual flower, the other is pedunculated with a male flower. Bisexual, but with unisexual spikelets, the inflorescences of the South American herbaceous bamboo plant Piresia (Piresia) are located on creeping rhizomatous 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 spikelets 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 wrapped in sheath-shaped leaves (Fig. 209, 1-3). Even more original is the arrangement of same-sex spikelets in the South Asian relative of corn, Coix. The lower, female part of the spicate 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. Long stigmatized branches of the female flower and the stem of the male part of the branch, which is a rather dense false spike, emerge from its upper part (Fig. 210, 7).

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Examples of dioecious cereals are pampas grass (Cortaderia selloana, pl. 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). Quite widely represented among cereals are various methods of asexual reproduction. In particular, vegetative propagation using creeping rhizomes, as well as creeping and rooting at the nodes of above-ground shoots, is found in very many perennial grasses. Mostly rhizomes propagate, for example, common reed, in extratropical countries only rarely forming normally separated grains. Some ephemeroid cereals 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 turfs are broken by herbivores, and the bulbs are carried by the wind or on the legs of animals across the pasture.

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No less common in cereals is asexual reproduction with the help of those parts or organs of the plant that are related to sexual reproduction. Viviparia belongs here, 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 the panicle into such buds is found in a number of arctic grasses from the genera bluegrass, fescue, pike, as well as in 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 may also arise as a result of hybridization between species.

Cases of apomixis in the narrow sense of the 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 tribes of millet and sorghum. Of the extratropical grasses, there are many apomictic and semi-apomictic species in the genera bluegrass and reedgrass.

For cereals, highly specialized anemophilous plants, the daily rhythm of flowering and pollination is of particular importance. The exact coincidence of the flowering of all individuals of a given species during any limited time of the day greatly increases the chances of cross-pollination and is an important adaptation to the increasingly perfect anemophily. Among extratropical grasses, there are several groups of species that differ 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 only in a few extratropical grasses. However, in hot and dry areas of the tropics, night flowering is known in many species, as it avoids overheating and rapid pollen death during a hot day. Interestingly, night-blooming tropical grasses tend to bloom early in the morning when outside the tropics, as the risk of pollen overheating is reduced. In cereals that bloom at noon and in the afternoon, flowering occurs at the hottest time of the day. Pollen grains at this time wrinkle and die relatively quickly, however, 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, also characteristic of many cereals, not one, but several such explosions of flowering occur during the day. It was 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 diurnal rhythm of flowering in cereals turned out to be a good species systematic trait.

The unit of distribution of fruits - the diaspora - in cereals is usually an anthecia: a caryopsis enclosed in lemmas with a segment of the spikelet axis adjacent to them. Bare (devoid of any scales) grains, whole spikelets, parts of the common inflorescence, the entire common inflorescence, or even the entire plant serve as diaspores much less frequently. In the small sheath of a flower mentioned above, grains strongly protruding from the flowering scales fall out of them and are carried by water during fluctuations in the level of rivers associated with floods, rains, changes in wind direction, etc. The psammophilic ephemeral Palestinian sandbox can serve as a rare example when grains falling out of spikelets dispersed by the wind. In the sporobolus (Sporobolus), which is widespread in the tropics, sac-like grains, when wetted with rain or dew, quickly swell, burst, and the seeds squeezed out of them, surrounded by sticky mucus, hang from spikelets, sticking to animal hair and bird feathers. Large grains of many bamboos that fall out of spikelets are spread mainly by water streams during tropical downpours, as well as with the help of birds. The berry-like grains of the melocanna begin to germinate on the mother plant, without a dormant period, then fall on the moist soil with a sharp end down and continue their development on their own. They can also spread with the help of birds and animals that eat them.

Distribution by whole common inflorescences or their parts is also not very rare in cereals. Spike-shaped panicles of whorled bristles (Setaria verticillata), very tenacious due to the presence of spines directed backwards on the spikelets surrounding the spikelets, often cling to animal hair or human clothing along with the stems. The ears of many species of Aegilops (Aegilops) with large awns protruding to the side are easily entangled in animal hair, but can be carried over long distances by wind. Groups of spikelets of maned barley (Hordeum jubatum), bearing very long and thin awns, can also be carried both by animals and by wind. In the latter case, numerous groups of spikelets can interlock together, forming a spherical tumbleweed that is carried by the wind over long distances, especially along highways. Many other grasses are dispersed by the wind in a tumbleweed type, the basis of the latter being very large, widely and sparsely branched panicles. Examples of this kind are the Siberian bluegrass (Poa subfastigiata) or the Lower Volga Bieberstein's scurvy (Zingeria biebersteinii). In the littoral Asian and Australian genus Spinifex (Spinifex, Fig. 211, 3), the female common inflorescences, which are almost spherical in shape, fall off entirely, then roll over the sandy coast or swim in the water and, having already lingered somewhere, gradually disintegrate. Very curious is the way of distribution of the splayed snake (Cleistogenes squarrosa) - one of the characteristic plants of the steppes and deserts of Eurasia (Fig. 194, 2). The stems of this species, when fruiting, bend serpentine and break off at their base. Clutching with each other, they form a tumbleweed that is 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 there are shortened branches with cleistogamous spikelets.

In cereals, the spread of diaspores with the help of wind and animals is almost equally represented, and in many cases diaspores can spread in both ways (for example, in the common feather grass tyrsa in the steppes of Eurasia - Stipa capillata). Apparently, in the course of evolution, in many groups of cereals, there was a transition from a predominantly zoochoric mode of distribution to a predominantly anemochoric one. So, in the genus reed grass diasporas of more ancient, forest species (reed reed grass, etc.) have long articulated awns and a bunch of short stiff hairs on the callus - an adaptation to zoochory, and diaspores of a relatively younger species of ground reed grass (Сalamagrostis epigeios) are equipped with very a short awn and a bunch of very long (longer than lemmas) hairs on the callus, spreading exclusively anemochorically. Species of the genus Achnatherum, often combined with feather grass, but of a more primitive genus (Achnatherum) also have small zoochornically spreading diaspores, while among feather grass highly specialized anemochoric species are known with very long (40 cm or more), doubly articulated and pinnately hairy awns in the upper part. . A long and sharp callus with stiff hairs directed upwards makes it possible for feather grass diaspores to screw into the soil, as it were. At the same time, 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 twists or unwinds, moving the lemmas with the caryopsis deeper and deeper into the soil. In some feather grasses that can spread on animal fur, such as the feather grass tyrsa, diaspores can screw into their skin, causing serious damage to animals.

An increase in the windage of diaspores in anemochory grasses is especially often carried out due to long hairs, which can be located on the sides of the lower lemma (in the transylvanian barley - Melica transsilvanica), on the strongly elongated callus of the lower lemma (in the reed), on the segment of the spikelet axis above the base floral scales (in many species of reed grass), on strongly elongated awns (in many feather grasses). In the common in the sandy deserts of Eurasia, the cirrus selin (Stipagrostis pennata) divides the awn 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 lemmas, and in the Persian nine-tail (Enneapogon persicus) it looks like a transverse row of 9 pinnately hairy awns. Easily carried by the wind are thick, but very light segments of ears of psammophilous genera - two scales (Parapholis) and one scales (Monerma). The windage of diaspores, consisting of a whole spikelet, can increase due to winged spikelet scales (in canary - Phalaris) or due to their sac-like swelling (in Beckmannia - Beckmannia). In the shaker (Briza), the windage of the diaspore-antecium increases due to the greatly expanded and almost completely membranous lower lemmas.

Adaptations of cereals to zoochory are no less diverse. Especially often, their diaspore-antecia have articulated rough awns and stiff hairs on the callus, however, in representatives of the genus goat (Tragus) and some other genera, hooked spikes are located in rows on the back of the lower lemmas. In the herbaceous bamboo cochlear leptaspis (Leptaspis cochleata), the closed and swollen lower lemmas, falling together with the caryopsis, are covered with small spines hooked at the apex and are easily attached to animal hair (Fig. 197, 4). In Cenchrus, rather large spiny heads spread exozoochorically, consisting of several spikelets enclosed in a wrapper of expanded and fused in the lower part of the bristles - modified branches of the common inflorescence (Fig. 202, 8-9). Fruiting spikelets of the tropical genus Lasiacis (Lasiacis) are dispersed by birds that are attracted to thickened spikelet scales rich in oils. The diaspores of many species of barley (Melica) have succulent appendages of underdeveloped lemmas at the top of the spikelet axis and spread with the help of ants that eat these appendages.

Diaspores 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 unwinding of the awns. At present, both the conscious and unconscious role of man in the distribution of cereals has increased tremendously. The ranges of cultivated species are expanding significantly, often along with their specific weeds. Many cereals from other continents are introduced into culture as fodder plants, and then many cereals from other continents go wild (for example, rootless couch grass or New England elimus - Elymus novae-angliae, introduced from North America, is widespread in the USSR). Many species of cereals that have long been introduced into culture have lost the mode of distribution characteristic of their ancestors. So, in cultivated species of wheat, rye, barley, the ears do not break up into segments; cultivated oats do not have articulations on the axis of the spikelet; chumiza and mogar (Setaria italica) do not have articulations at the base of spikelets, which are typical for wild-growing representatives of this genus. Only in culture are known cereals such as corn and cob that are unable to reproduce without human help.

When the grain germinates, first of all, the germinal root begins to grow, and then the bud of the embryo, covered with a coleoptile. After the coleoptile emerges on the soil surface, the first leaf of the seedling protrudes from it, which continues to rapidly elongate 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 directed upwards (it occurs 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 in panicoid tribes). In addition, there is an intermediate eragrostoid type between them, and recently 2 more types have been identified - bambusoid and orizoid, in which, on the axis of the seedling, after the coleoptile, not ordinary leaves follow, but one or more cataphylls - scaly leaves, and with bambusoid In the type characteristic of the subfamily Bamboo, the first fully developed leaf of the seedling is built according to the panicoid type, while in the case of the orizoid type characteristic of the subfamily Rice, it is closer to the festucoid type.

The initial versions of the cereal system were based mainly on easily conspicuous features in the structure of common inflorescences and spikelets. For a long time, the system of a well-known cereal specialist, E. Gakkel (1887), was generally accepted. This system was built on the principle of gradual complication in the structure of spikelets, from the tribes of sorghum and millet, usually having spikelets with a single developed flower, to bamboo, many of which have many-flowered spikelets of a very primitive structure. However, already at the beginning of the XX century. a lot of 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, the structure of starch grains, which made it possible to radically revise the Hakkel 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 the spikelet, flowering films, stamens and stigma branches.

Important data for the construction of 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 found that the size of chromosomes and their main number (x) in the cereal family are signs not only constant within most genera, but also characteristic of larger subdivisions of this family. Relatively small chromosomes with a basic number equal to 6, 9, and 10 turned out to be characteristic mainly of tropical tribes of cereals (sorghum, millet, pigs, etc.), and larger chromosomes with a basic number of 7 - mainly to 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 having small chromosomes, and fescue (Festuciformis) with most extratropical tribes of cereals with large chromosomes, usually in multiples of 7.

Avdulov's system became the basis for subsequent cereal systems, in which the bamboo subfamily (Bainbusoidae) took the first place. Based on the features mentioned above, 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 - bluegrass (Pooideae), reed (Arundinoideae), field grasses ( Eragrostoideae) and millet (Panicoideae) - form a gradual transition from the full set of festucoid characters characteristic of extratropical cereals to the 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 so consistent as it seemed at first, as a result of which they are not recognized by all authors. Thus, among the millets, there were a number of species (including those in the genus millet) with festucoid leaf anatomy (and, therefore, without krantz 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, short-legged - Brachypodium) and genera with a basic number of chromosomes 6 (canary - Phalaris), 9 (barley) and 10 (mannik) . Recently, two festucoid cereals, Zingeria biebersteinii and Colpodium versicolor, have been found to have the lowest total number of chromosomes in higher plants (2n = 4) with a main chromosome number of 2. Previously, such a number was known only in one American species from the Compositae family. Even within the same festucoid species, the Mediterranean spring ephemeral (Milium vernale), races with the main numbers of chromosomes 5, 7, and 9 have been identified.

Forest herbaceous plants Wikipedia - ? Zingeria Biberstein Scientific classification Kingdom: Plants Department: Flowering plants ... Wikipedia

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

To date, more than 350 thousand plant species are known. Of these, about 60,000 species fall into the class Monocots. At the same time, this class includes the two most common families in terms of habitat and economic importance:

• Lily.
• family Cereals or Bluegrass.

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 Cereal family are found both in meadow and cultivated plants, which are of great agricultural importance.

Growing conditions and distribution

The Cereal 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 Cereal family are very unpretentious to growing conditions. So, for example, representatives of meadow grasses (timothy grass, bluegrass, couch grass, hedgehog, bonfire and others) quite calmly endure the adverse conditions of winter and the heat of summer.

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

Almost all representatives, which include the Cereal family, are equally neutral towards 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 during periods of low light.

General characteristics of the family

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

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 protein, and fourth for decorative purposes.

Morphological features

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

1. Straw stalk (except corn and reed), 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 sheet plates is next.
7. type, sometimes underground shoots turn into rhizomes.

All representatives that form the Cereal family have such signs.

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. Gathered in inflorescences of different types:

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

The flowers are the same for everyone, the formula of the flower of the Cereal family is as follows: TsCh2 + Pl2 + T3 + P1. Where TsCh - flower scales, Pl - films, T - stamens, P - pistil.

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

Fruit

After flowering, a fruit rich in protein and starch is formed. It is the same for all members of the Cereal family. The fruit is called a grain. Indeed, most people who are 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 cereals

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

Wild representatives:

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

Most representatives of wild-growing Cereals are inhabitants of the steppes, meadows, forests, savannahs.

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

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

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

annual plants

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

It is difficult to give an example of any one annual plant of the Cereal family. There are actually quite a few of them. Consider a few of the most common and commercially important.

1. Kaoliang. A plant from the genus Sorghum, is on a par with rye, wheat and so on.
2. Durra or Jugarra. Also a fodder plant, which is most common 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 in the grass family, which is often accepted and regarded as a weed. It grows on any soil, unpretentious to heat and moisture, can do without sunlight for a long time. It is used only for animal nutrition, its fruits have no economic value.
4. Corn. One of the most common agricultural crops in many countries of the world. Oils, flour are obtained from corn grains, the grains themselves are used directly in boiled form.
5. Foxtail. A herbaceous plant that belongs to both annual and perennial forms. The main value is the formation of grass cover in meadows (flooded). Goes to feed animals.
6. Panic. Southern agricultural annual crop, which is grown not only for livestock feed, but also as a food plant for 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 types. Of 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 grain for animal feed.

perennial plants

Most of the plants in the family are perennials. That is, they consist of several seasons (vegetation periods). They are able to survive the adverse conditions of winter periods without loss of viability. Many of them form the Cereal family. The characteristics of such plants are very extensive. Consider some of the most important representatives in economic terms.

1. Wheat. The most widespread agricultural crop in terms of the world's area, 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 fodder base for animal nutrition.
3. Rice. A very important agricultural crop, 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 sought after cereals after wheat and rice. A large number of these plants are grown here in Russia. The nutritional value of grain is high.
5. Sugarcane. His homeland is India, Brazil and Cuba. The main nutritional value of this crop is the extraction of sugar.

Agricultural crops Cereals

In addition to the above listed, sorghum can also be attributed to agricultural crops of this family. This plant has all the characteristics of the Cereal family, and also has valuable grain. In our country, sorghum is not grown, as it is a very heat-loving 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 are fed to livestock. In addition, furniture is made from leaves and stems, beautiful interior items are woven.

Barley can also be attributed to important agricultural crops. This plant does not require special conditions for growth, therefore it is easily cultivated in the territories of many countries. The main value of grain goes to brewing, obtaining pearl barley and barley groats, 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 grains

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

Firstly, all grains of Cereals contain protein, just the amount of it in different representatives varies. Wheat varieties are considered to have the highest content of gluten protein.

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

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

Obviously, the full use of cereals provides the body with a set of all the daily necessary substances. That is why they are so popular all over the world.