Fertile parts of the flower (stamen, pestle). Sterile parts of the flower (calyx, corolla, perianth). A flower is an organ of seed propagation of angiosperms. The formation of micro- and megapores, gametes, pollination, fertilization, development of the embryo and the formation of the fetus with seeds occur in the flowers. The flower consists of a peduncle, receptacle, perianth, androecium and gynoecium.

The pedicel is the internode under the flower; it connects it to the stem. Flowers without pedicels are called sessile. On the peduncle, there may be leaves called bracts. The receptacle is an extended part of the peduncle, to which all other parts of the flower are attached. Most plants have flowers with pistils and stamens and are bisexual. Some plants have same-sex flowers. Actinomorphic, zygomorphic and asymmetric are distinguished depending on the symmetry. Perianth is simple and double, double perianth consists of a calyx and corolla, the calyx mainly performs a protective function consisting of sepals more often colored in green, they can be free and fused (like legumes) and form a soldered or bell-shaped cup. In some groups of plants, the calyx is reduced (umbellate) or modified (asteraceae). Corolla has a diverse color and size, as a rule, significantly exceeds the cup. It consists of petals. Petals of insect-pollinated plants are painted in bright colors. Wind pollinators are inconspicuous or absent. A simple perianth consists of identical leaflets and is characteristic of most monocotyledons, as well as some dicotyledons. It is more often corolla-shaped (brightly colored) and sometimes calyx-shaped (green). The set of stamens in a flower is called androecium. The stamen consists of a stamen filament and anther. The anther is made up of two halves, each of which is represented by two microsporangia (pollen bags). A sporogenous tissue forms in the pollen bag, forming microspores (pollen grains), and during their formation, meiosis occurs. Pollen grain is haploid, has two shells and is carried through the air. A male gametophyte develops in it, which is very reduced and consists of 2 cells: vegetative and generative. The generative cell replaces the anteridium and gives rise to two sperm - male gametes, in contrast to spermatozoa lacking flagella. A pollen tube is subsequently formed from a vegetative cell. Gynoecium is a collection of carpels in a flower that form one or more pistils. Gynoecium can consist of free carpels, each of which forms a pestle. This type of gynoecium is characteristic of primitive flowering (ranunculaceae, legumes). In the process of evolution, carpels have grown together and formed a more complex type of gynoecium. The number of carpels that formed such a gynoecium can be determined by the number of posts on one ovary, the number of stigmas, the number of nests of the ovary. In a typical case, the pestle differentiates into ovary, column and stigma. Depending on the type of receptacle, the ovary may occupy different positions in relation to other organs of the flower. Ovaries are located inside the ovary, the number of which can vary from one to several million. Ovule (megasporangium) is the multicellular formation of seed plants, from which the seed subsequently develops. The ovule is surrounded on the outside by integuments that do not close at the apex, forming a narrow channel - a micropile (pollen feeder). Through a micropile, the pollen tube penetrates the embryo sac. 4 haploid megaspores are formed from a single diploid cell of the ovule as a result of meiosis. Three of them die, and one continues to develop. It is divided mitotically three times, as a result of which 8 haploid nuclei are formed. Two of them merge in the center, forming a diploid nucleus. So there is a female gametophyte, called the embryo sac. In a mature female gametophyte, there are an egg, a diploid central cell, and a number of additional cells.

Flower functions.

A flower is a modified shortened shoot adapted for propagation of angiosperms (flowering) plants.

The exclusive role of the flower is due to the fact that all the processes of asexual and sexual reproduction are combined in it, while in the lower and many higher plants they are disconnected. In a bisexual flower, micro- and megasporogenesis, micro- and megagametogenesis, pollination, fertilization, and the formation of seeds and fruits are carried out. The structural features of the flower allow these functions to be carried out with minimal expenditure of plastic substances and energy.

Formula and diagram of a flower.

Flower Chart. 1 - the axis of inflorescence, 2 - bracts, 3 - sepals, 4 - petal, 5 - stamen, 6 - pistil, 7 - covering sheet.

For a short and symbolic designation of the flower structure, formulas are used in which various morphological characters are encoded using alphanumeric symbols: the sex and symmetry of the flower, the number of circles in the flower, as well as the number of members in each circle, the fusion of parts of the flower and the position of the pistils (upper or lower ovary).

The flower formula is a brief description, its description with the help of symbols. The flower is studied in an acropetal order and in this sequence the following symbols are written: polysymmetric flower (actinomorphic) - *, zygomorphic -, asymmetric - │ :, - then the cup symbol - K (Ca), corolla - C (Co), androecium - A, Gynoecium - G, simple perianth (region) - P. The number of elements of each part of the flower is indicated by the corresponding number, but if there are more than twelve of these elements, ∞; the fact of the fusion of the flower parts is indicated by brackets, the placement of this part of the flower in different circles is separated by a + sign. The upper ovary is affected by a dash (-), placed under the Carpel number by the gynoecium, the lower ovary - above the number, and the middle - along with the Carpel number. For example, the formula of a rape flower (Barbareа) looks like this: * K4C4A2 +4 G (2); pears (Pyrus): * K5C5A ∞ G (5); Tulip (Tulipa): P3 +3 A3 +3 G (3) -; elderberries (Sambucus): * K5C5A5G (3) -.

The most complete picture of the structure of the flower is given by diagrams that represent a schematic projection of the flower onto a plane perpendicular to the axis of the flower and passing through the covering sheet and the axis of the inflorescence or shoot on which the flower is located.

Fertile parts of the flower (stamen, pestle). Sterile parts of the flower (calyx, corolla, perianth). A flower is an organ of seed propagation of angiosperms. The formation of micro- and megapores, gametes, pollination, fertilization, development of the embryo and the formation of the fetus with seeds occur in the flowers. The flower consists of a peduncle, receptacle, perianth, androecium and gynoecium.

The pedicel is the internode under the flower; it connects it to the stem. Flowers without pedicels are called sessile. On the peduncle, there may be leaves called bracts. The receptacle is an extended part of the peduncle, to which all other parts of the flower are attached. Most plants have flowers with pistils and stamens and are bisexual. Some plants have same-sex flowers. Actinomorphic, zygomorphic and asymmetric are distinguished depending on the symmetry. Perianth is simple and double, double perianth consists of a calyx and corolla, the calyx mainly performs a protective function consisting of sepals more often colored in green, they can be free and fused (like legumes) and form a soldered or bell-shaped cup. In some groups of plants, the calyx is reduced (umbellate) or modified (asteraceae). Corolla has a diverse color and size, as a rule, significantly exceeds the cup. It consists of petals. Petals of insect-pollinated plants are painted in bright colors. Wind pollinators are inconspicuous or absent. A simple perianth consists of identical leaflets and is characteristic of most monocotyledons, as well as some dicotyledons. It is more often corolla-shaped (brightly colored) and sometimes calyx-shaped (green). The set of stamens in a flower is called androecium. The stamen consists of a stamen filament and anther. The anther is made up of two halves, each of which is represented by two microsporangia (pollen bags). A sporogenous tissue forms in the pollen bag, forming microspores (pollen grains), and during their formation, meiosis occurs. Pollen grain is haploid, has two shells and is carried through the air. A male gametophyte develops in it, which is very reduced and consists of 2 cells: vegetative and generative. The generative cell replaces the anteridium and gives rise to two sperm - male gametes, in contrast to spermatozoa lacking flagella. A pollen tube is subsequently formed from a vegetative cell. Gynoecium is a collection of carpels in a flower that form one or more pistils. Gynoecium can consist of free carpels, each of which forms a pestle. This type of gynoecium is characteristic of primitive flowering (ranunculaceae, legumes). In the process of evolution, carpels have grown together and formed a more complex type of gynoecium. The number of carpels that formed such a gynoecium can be determined by the number of posts on one ovary, the number of stigmas, the number of nests of the ovary. In a typical case, the pestle differentiates into ovary, column and stigma. Depending on the type of receptacle, the ovary may occupy different positions in relation to other organs of the flower. Ovaries are located inside the ovary, the number of which can vary from one to several million. Ovule (megasporangium) is the multicellular formation of seed plants, from which the seed subsequently develops. The ovule is surrounded on the outside by integuments that do not close at the apex, forming a narrow channel - a micropile (pollen feeder). Through a micropile, the pollen tube penetrates the embryo sac. 4 haploid megaspores are formed from a single diploid cell of the ovule as a result of meiosis. Three of them die, and one continues to develop. It is divided mitotically three times, as a result of which 8 haploid nuclei are formed. Two of them merge in the center, forming a diploid nucleus. So there is a female gametophyte, called the embryo sac. In a mature female gametophyte, there are an egg, a diploid central cell, and a number of additional cells.

Flower functions.

A flower is a modified shortened shoot adapted for propagation of angiosperms (flowering) plants.

The exclusive role of the flower is due to the fact that all the processes of asexual and sexual reproduction are combined in it, while in the lower and many higher plants they are disconnected. In a bisexual flower, micro- and megasporogenesis, micro- and megagametogenesis, pollination, fertilization, and the formation of seeds and fruits are carried out. The structural features of the flower allow these functions to be carried out with minimal expenditure of plastic substances and energy.

Formula and diagram of a flower.

Flower Chart. 1 - the axis of inflorescence, 2 - bracts, 3 - sepals, 4 - petal, 5 - stamen, 6 - pistil, 7 - covering sheet.

For a short and symbolic designation of the flower structure, formulas are used in which various morphological characters are encoded using alphanumeric symbols: the sex and symmetry of the flower, the number of circles in the flower, as well as the number of members in each circle, the fusion of parts of the flower and the position of the pistils (upper or lower ovary).

The flower formula is a brief description, its description with the help of symbols. The flower is studied in an acropetal order and in this sequence the following symbols are written: polysymmetric flower (actinomorphic) - *, zygomorphic -, asymmetric - │ :, - then the cup symbol - K (Ca), corolla - C (Co), androecium - A, Gynoecium - G, simple perianth (region) - P. The number of elements of each part of the flower is indicated by the corresponding number, but if there are more than twelve of these elements, ∞; the fact of the fusion of the flower parts is indicated by brackets, the placement of this part of the flower in different circles is separated by a + sign. The upper ovary is affected by a dash (-), placed under the Carpel number by the gynoecium, the lower ovary - above the number, and the middle - along with the Carpel number. For example, the formula of a rape flower (Barbareа) looks like this: * K4C4A2 +4 G (2); pears (Pyrus): * K5C5A ∞ G (5); Tulip (Tulipa): P3 +3 A3 +3 G (3) -; elderberries (Sambucus): * K5C5A5G (3) -.

The most complete picture of the structure of the flower is given by diagrams that represent a schematic projection of the flower onto a plane perpendicular to the axis of the flower and passing through the covering sheet and the axis of the inflorescence or shoot on which the flower is located.

Since the XIX century. in academic work and in scientific research, formulas and diagrams are used for greater clarity. Flower formula  - the symbol of its structure using the letters of the Latin alphabet, symbols and numbers. In the preparation of the formula, use the following notation: I - a simple perianth (perianthium); Ca  (or K) - a cup (calyx); With  (or C) - whisk (corolla); BUT -  androecium (androeceum); G  - gynoecium (gynoeceum);  the * sign placed at the beginning of the formula indicates the actinomorphism of the flower; the sign is its zygomorphism. A bisexual flower is indicated by a male sign - ♂; female - ♀. The “+” sign indicates the location of the flower parts in two or more circles or that the parts separated by this sign are opposed to each other. Brackets mean the fusion of parts of a flower. The number next to the symbol indicates the number of members of this part of the flower; a line under the number indicating the number of carpels in the gynoecium, for example 3, indicates that the ovary is superior; the line above the figure is the lower ovary; a line from the figure is a half-low ovary. A large and indefinite number of members is denoted by ∞.

For example, the tulip flower formula * P 3 + 3 A 3 + 3 G (3) shows that it is actinomorphic, has a simple six-membered perianth, the free lobes of which are located three in two circles; androecium is also six-membered, from two circles of stamens, and gynoecium is cenocarpous from three fused carpels (compound pistil), forming the upper ovary.

Dandelion Flower Formula Ca 0 Co (5) A  (5) G (2) or (1) indicates that its flowers are zygomorphic, bisexual, have a perianth, in which the calyx is reduced, the corolla consists of five fused petals, androecium - of five stamens that are stuck together by anthers, and gynoecium - of two fused carpels forming the lower ovary. Since only one of the two fused carpels develops, i.e., the pseudomonocarpous gynoecium, a more rational notation is also possible for the dandelion flower formula G  (one ) . Formula of cassock flower white   Ca (5) Co (2+3) A  4 G (2) indicates its zygomorphism,. bacillus, double perianth, in which the calyx consists of five fused sepals, and the corolla consists of five fused petals, of which two oppose the other three; the androecium is formed by four free stamens, and the coenocaric gynoecium is formed by two fused carpels forming the upper ovary.

A flower diagram is more visual than a formula. It represents a conditional schematic projection of the flower parts on a plane and reflects their number,

relative sizes and relative position, as well as the presence of intergrowths (Fig. 99). In addition, the diagram often indicates the location of the covering (bract) leaf, bracts and the axis of the inflorescence or shoot bearing the flower. Bracts, bracts and sepals are more often represented with brackets with keel (curly braces) of various sizes, petals with parentheses, stamens as a slice through the anther or, for simplification, as a shaded ellipse, a genius as a slice through the ovary or ovary (for apocarpous gynoecium ) with a drawing of the place of placentation and ovules through which the slice passed.

For a brief record of the structure of the flower in botany, formulas and diagrams are used that give a visual representation of the structure of the flower.
The flower formula is a brief description of the structure of the flower using letters, numbers and signs. Each part of it is indicated by the initial letter of the names of the flower. The cup is called Calyx (Ca), the corolla is Corolla (Co), the set of stamens is Androeceum (A), the set of pistils is Gynoeceum (G). A simple perianth is called Perigonium and is indicated in the formula by the letter P. The number of members of the individual parts of the flower is expressed by a number and is indicated in the formula as an index on the right side. For example, a five-crowned corolla - Ca5 or androecium six-membered - A6. If the number of flower parts is more than 12, then instead of a digit write the sign ∞. In the case of intergrowth of flower parts, the number indicating their number is enclosed in brackets Ca (5). In the case of partial intergrowth of flower parts in the formula, write a number in brackets through the plus sign, for example, A1 + (9). If the flower parts are arranged in circles, then the numbers indicating their number in the whorls (circles) are connected by a + (plus) sign. For example, perianth lily P3 + 3. In the formulas, you need to designate the type of ovary by location on the receptacle (upper, lower, middle). The initial letters of the names of the parts of the flower with the indices are written in one line, for example: Ca (5) Co5A∞G (5).
If the ovary is upper, then the figure indicating the number of carpels is emphasized from below, if the lower is from above. For example, G (3) or G (5) means that the pistil in the flower is one, but it is formed by three or five carpels.
Symbols of the formula of flowers: * - actinomorphic flower; - zygomorphic flower; ♂ - stamen flower; ♀ - pistil flower. For example, the formula of the flower of cabbage * Ca4Co4A2 + 4G (2), apple * Ca (5) Co5A∞G (5), lily * P3 + 3A3 + 3G (3).
An even more complete picture of the structure of a flower is provided by a diagram representing the projection of a flower onto a plane perpendicular to its axis. In drawing up the diagrams, the following conventions are used: О - the axis of the flower, the sepals and keel are indicated by the crescent-shaped arches with the keel, the petals are indicated by the crescent-shaped arches without a keel, the stamens by the shape of the cross section through the anther, and the pestle by rings reflecting the cross section through the ovary (Fig. 2).

Fig. 2. Building a flower diagram: 1 - the axis of the flower; 2 - (bract) covering sheet; 3 - bracts; 4 - sepals; 5 - petals; 6 - stamen, 7 - gynoecium.

The diagram is designed so that the covering sheet is at the bottom, the inflorescence axis is at the top, and parts of the flower are located between them in circles of conventional symbols. When the parts of the flower grow together in the diagram, the conventional signs are interconnected by a line.