Angiosperms. Taxonomy of angiosperms Classification scheme for angiosperms flowering plants
The department of flowering plants is divided into two classes: dicotyledonous And monocots. Representatives of these classes differ in a number of characteristics.
The dicotyledonous class is distinguished by the reticulate venation of the leaf. The leaf is clearly distinguishable by its structure into upper and lower sides. The primary root is maintained as a central tap root from which lateral roots (secondary roots) extend. The seed embryo has two cotyledons (the first leaves to develop in the seed). The parts of the perianth vary and form the calyx and corolla. The number of parts is mainly a multiple of 4 and 5. Most often they are pollinated by insects. Example: peas, beans, roses, buttercups, dandelions.
The monocot class is distinguished by lanceolate (oblong) leaves with parallel veins. The lower and upper surfaces of the leaves are identical. There is usually no cambium in the vascular bundles, so the stem cannot grow in thickness (there are exceptions, for example palm trees). The adventitious roots extending from the base of the stem do not differ from the primary root; the root system is fibrous. The embryo has one cotyledon. The number of flower parts is a multiple of 3. The perianth parts are the same, there is no obvious division into a calyx and corolla. Most often pollinated by wind. Example: cereals, irises, orchids, lilies.
7. The importance of higher plants
Plants are the first to produce organic matter in the process of photosynthesis, and therefore play the role of producers in ecosystems.
The minerals used by humans today are: peat, brown and hard coal- this is nothing more than the remains of fossil plants that existed in the past on Earth. Plants are used by humans as food, provide building materials, medicines and raw materials for a number of industries. Plants form plant communities, forming the basis of all natural communities, i.e. biogeocenoses.
Lecture 8. Diversity of the organic world
2. Diversity of unicellular organisms
3. Diversity of multicellular animals
4. Diversity of chordates
5. Features and ecological and biological role of fungi
6. Lichens
1. General characteristics of animals
Animals are a kingdom of eukaryotic living organisms that share common characteristics:
2. The absence of a strong cell wall in most cells;
3. Most species have mobility, and therefore have a nervous system and sensory organs;
4. Irritability;
5. Limited growth;
6. Pronounced symmetry of the body. Animals with an active lifestyle are characterized by bilateral (two-sided) symmetry. Radial symmetry is characteristic of animals leading a sedentary or motionless lifestyle.
Nowadays, about one and a half million species of a wide variety of animals are known.
2. Diversity of unicellular organisms
Depending on the origin and body structure of animals, he classifies organisms into two subkingdoms - unicellular and multicellular animals.
The characteristic features of representatives of the unicellular subkingdom is that they consist of one cell and there are no tissues. There are specialized organelles: cell mouth, contractile vacuoles. Autotrophs and heterotrophs are represented. They reproduce by fission in two or sexually; During sexual reproduction, the entire body of the protozoan breaks down into gametes. They live mainly in humid environments: in fresh waters and seas, in swamps and in moist soil.
Let's consider the features of biology and the significance of the 4 most famous classes of unicellular organisms: flagellates, rhizopods, ciliates, sporozoans.
Body of Type Representatives ciliates covered with pellicle, giving the body a permanent shape. They move with the help of cilia. There are two nuclei located in the cytoplasm: generative (small) and vegetative (large). The most famous species: slipper ciliate, trumpeter ciliate.
3. Diversity of multicellular animals
Most representatives of the multicellular subkingdom are characterized by the presence of tissues. All types of heterotrophic nutrition are represented. Reproduction is predominantly sexual. Aquatic and truly terrestrial forms that can exist outside of water. Let us briefly characterize the most important types of multicellular animals.
Type sponges- the most primitive multicellular organisms. These are mainly marine animals attached to the bottom and underwater objects. In nature they play a significant role as water biofilters.
Type Coelenterates are two-layered multicellular animals: the body wall consists of two layers of cells - the outer (ectoderm) and the inner (endoderm). Primitive tissues appeared. One body cavity. The only opening for swallowing food and excretion. The structure of the body shows radial symmetry. The nervous system is a network. Asexual reproduction by budding. During sexual reproduction, a mobile larva is formed.
There are attached polyp forms, which can be solitary or colonial; There are free-swimming single forms - jellyfish. These are hydras, jellyfish, polyps, sailboats, siphonophores, sea anemones, corals, etc.
They form a significant mass of marine zooplankton. Coral polyps form the environment for the most productive tropical marine community, coral reefs. There are poisonous species of jellyfish.
Class ciliated- aquatic, free-living worms. The body is tender, soft, and leaf-shaped. There are no suckers, the body is covered with cilia. There is a gut. Adults have sensory organs. Simple life cycle. Example: planaria.
Type ringed worms Includes about 9 thousand species that have a more complex organization than representatives of other types of worms. The segmentation of the body is clearly expressed. The central nervous system forms the “brain”. There is a closed circulatory system, with “hearts”, the blood is red. These include the tubifex, earthworm, earthworm, and leeches.
Type shellfish There are up to 130 thousand species. These are inhabitants of salt and freshwater bodies of water. The body consists of a head, legs and torso. The outer integument is soft, forming a fold-mantle around the body, which secretes the shell. There is a heart and an open circulatory system. They usually lay eggs. Most mollusks play an important role as water biofilters. Representatives of three classes are most important. Class Gastropods (reel, pond snail, snail, slug). Class bivalve (pearl mussel, scallop, mussel, oyster). Class Cephalopods (cuttlefish, squid, octopus).
Type arthropods. Segmented animals are bilaterally symmetrical. The whole is largely reduced. The central nervous system consists of paired perioral ganglia connected to the ventral nerve cord; The abdominal nerve chain unites nodes and nerves located segment by segment. A chitinous exoskeleton is distinguished. Each segment carries, as a rule, a pair of jointed limbs that perform the functions of movement, food extraction, or perception of irritation. The heart is located on the dorsal side, the circulatory system is not closed. Variety of larval forms in different representatives of the type. Representatives of three classes are most important. Class crustaceans (cyclops, woodlice, shrimp, lobster). Class arachnids (taiga tick, karakurt, cross spider). Class insects (ant, bee, dragonfly, locust).
The department Angiosperms is divided into two classes: Dicotyledons and Monocots. Representatives of these classes differ primarily in the structure of the seed: the seed embryo of dicotyledons has two cotyledons, of monocotyledons - one (hence the name of the classes). Other differences between them are presented in table. 9.1.
However, among mono- and dicotyledons there are plants whose individual characteristics do not coincide with those listed in the table. 9.1. Thus, in the crow's eye (class Monocots) the leaf venation is pinnate, and in the plantain (class Dicotyledons) it is arcuate and has a fibrous root system. In this regard, it is possible to judge whether a plant belongs to a particular class only by a combination of characteristics.
Table 9.1. Distinctive characteristics of mono- and dicotyledonous plants.
|
Sign |
Monocots |
Dicotyledons |
|
Root system |
Fibrous, main root dies early |
Taproot, well developed main root |
|
Stem |
Herbaceous, incapable of secondary thickening, branches rarely. Vascular bundles without cambium, scattered throughout the stem |
Herbaceous or woody, capable of secondary thickening, branching. Conducting bundles with a cambium are located in one large mass in the center of the stem or have the appearance of a ring |
|
Leaves |
Simple, entire, usually without petiole and stipules, often with a sheath, parallel or arcuate venation. The leaves are arranged in two rows |
Simple or compound, the edges are entire, dissected or serrated, often with a petiole, stipules, reticulate or palmate venation. The arrangement of leaves is alternate, opposite |
|
Flower |
Three-membered, less often two or four-membered |
Five-, less often four-membered |
|
Pollination |
Most plants are wind pollinated |
Most plants are pollinated by insects |
Table 9.2. The main characters of some families of mono- and dicotyledonous plants.
|
Family |
Flower formula |
Fetus |
Inflorescence |
Examples |
|
Cruciferous or Brassicas (more than 3.2 thousand species) |
*H 4 L 4 T 2+4 P 1 |
Pod or pod |
Brush, less commonly scute or panicle |
Cabbage, rutabaga, radish, radish, turnip, horseradish, turnip, shepherd's purse, wild radish, field grass |
|
Rosaceae (about 3 thousand species) |
*H 5 L 5 T * P * *H 5 L 5 T * P 1 |
Assembled nut |
Single flowers |
Rosehip, strawberry |
|
Legumes, or Butterflies (about 12 thousand species) |
|H (5) L (5) T (9)+1 P 1 |
Bean |
Head |
Clover |
|
Solanaceae |
*H (5) L (5) T 5 R 1 |
Berry |
Brush or curl |
Nightshade, tomato, potato |
|
Asteraceae, |
*H 0 L 5 T (5) P 1 The calyx has become hairy or is missing. |
Achene |
Basket: |
Thistle |
|
Cereals, or Poagrass (more than 10 thousand species) |
|O (2)+2 T 3 P 1 |
Caryopsis |
Complex ear |
Wheat, rye, barley |
Conventions (for drawing up a flower formula): * - the flower is correct; | - the flower is wrong; O - simple perianth, consisting of only sepals or only petals; () - fusion of flower parts; * - an indefinitely large number of flower parts; Ch - sepals; L - petals; T - stamens; P - pistils.
This principle is used when grouping all living organisms into genera, families, orders and other taxonomic categories.
The classes Dicotyledons and Monocots are divided into families. Plants of each family have common characteristics. In flowering plants, the main characteristics are the structure of the flower and fruit, the type of inflorescence, as well as the features of the external and internal structure of the vegetative organs.
Class Dicotyledons includes 418 families, about 10 thousand genera and over 190 thousand species, which is approximately 3/4 of the species of flowering plants. This class includes the most important fruits and berries (apple, pear, cherry, grapes, citrus), fodder (turnips, rutabaga, clover, alfalfa), spinning (flax, cotton, hemp), oilseeds (sunflower, castor bean), and ornamental (roses, chrysanthemums, asters, dahlias), etc. They all belong to the same or different families and differ in a set of characteristics (Table 9.2).
Class Monocots forms about 122 families, over 3 thousand genera and about 63 thousand species. Monocots provide humans with bread. These include cereals (wheat, rice, rye, barley, corn, millet, etc.), some ovoids (onions, garlic, asparagus), and ornamental plants (lilies, tulips, hyacinths, asparagus, orchids).
The bulk of many hayfields and pastures in the conditions of Belarus and Russia are wild cereals - timothy, foxtail, bentgrass, bluegrass, etc.
180 species of climbing plants are listed in the Red Book of the Republic of Belarus, including 84 species of dicotyledons and 60 species of monocotyledons.
Source : N.A. Lemeza L.V. Kamlyuk N.D. Lisov "A manual on biology for those entering universities"
Diversity of wild and cultivated flowering plants and their classifications. Elementary concepts about systematic (taxonomic) categories - species, genus, family, class, department.
Flowering (angiosperm) plants- This is the most numerous plant division, occupying a dominant position in modern flora. Flowering plants exhibit various life forms: trees, shrubs, shrubs, herbs. Flowering plants have the following distinctive features: there is a flower - a modified shoot in which the processes of asexual and sexual reproduction take place; the seeds develop inside the fruit, which protects them from adverse influences and promotes dissemination; double fertilization; tissues are highly differentiated; the conducting system reaches the peak of its development - the vascular system is formed.
The department is divided into two classes: Monocots and Dicotyledons. In turn, classes are divided into families. Families are divided into genera, and genera into species. When describing species, the binary nomenclature introduced by C. Linnaeus is used. According to the principles of binary nomenclature, the first word in the name of a plant is a noun and denotes the genus. It is written with a capital letter. The second word is an adjective and means the name of the species. It is written in lowercase letters. For example, May lily of the valley, creeping buttercup, tricolor violet. Latin is used to describe plant names. This allows various local plant names to be unified, and botanists speaking different languages to understand each other.
The body of higher plants is divided into organs: root and shoot (with the exception of bryophytes, in which stems and leaves appear for the first time, but there are no roots yet). These organs contain many different tissues. Higher plants have a well-developed conducting system formed by phloem and wood. In higher plants, a complex system of integumentary tissues, a complex stomatal apparatus is formed, and conducting tissues develop.
A characteristic feature of higher plants is the correct change of generations - asexual sporophyte and sexual - gametophyte. Sporophyte is a diploid generation that produces haploid spores. Gametophyte - haploid sexual generation in the life cycle of plants that produces gametes; In angiosperms, the female gametophyte is the embryo sac and the male gametophyte is the pollen.
The main families of the Dicotyledonous class (Cruciferae, Rosaceae, Legumes, Solanaceae, Asteraceae).
Family Cruciferae covers approximately 3,200 plant species. These are mainly herbaceous annuals, biennials and perennials. There are shrubs and subshrubs.
The leaves are alternate, simple, without stipules, and may be dissected. The flowers are bisexual, with a double perianth. The calyx is formed by four free sepals. The corolla consists of four separate petals. The color of the petals is often yellow or white, less often purple or pink. There are six stamens: two short and four longer. At the base of the stamens there are nectaries. There is only one pestle.
The flowers are collected in a raceme inflorescence - simple or complex. The fruit is a pod or silique that opens with two valves from the base to the apex.
Among the cruciferous crops there are many vegetable and forage crops: cabbage (various forms), turnips, turnips, horseradish. Oilseed plants - mustard, rapeseed, camelina. Ornamental plants - gillyflower, night violet. There are malicious weeds - wild radish, cress, shepherd's purse. Essential oils, alkaloids, and fatty oils can accumulate in the seeds and vegetative organs of cruciferous plants.
Family Rosaceae has more than 3000 species. Among them there are annual and perennial herbs, deciduous and evergreen shrubs and shrubs, and trees.
The leaves are alternate, the flowers are collected in various types of inflorescences - raceme, umbel, corymb, etc. The flowers are bisexual with a double perianth. A characteristic feature of Rosaceae flowers is the formation of a cup, which is formed as a result of the fusion of the receptacle with the bases of sepals, petals, stamens and takes part in the formation of false fruits. A calyx of five (less often four) free sepals, sometimes with a subcup. Corolla of five (less often four) free petals. The color of the petals is white, yellow, pink, the number of stamens is a multiple of five. Pistil - one or many, the number of carpels ranges from one to infinity.
There are nectaries. Rosaceae are insect-pollinated plants. The fruits are varied: drupes, multileafs, multiroots, multidruplets, apple. Seeds without eudosperm.
Fruit and berry crops - cherry, plum, apple, pear, peach, apricot, strawberry, raspberry, etc. Medicinal plants - rose hips, cinquefoil. Ornamental plants - roses, spirea.
Family Legumes (Pataceae) unites 18,000 species, one of the richest plant family. Legumes include annual and perennial herbs, shrubs, shrubs and trees. Among the representatives of legumes there are deciduous and evergreen plants.
The leaves are compound, the leaf arrangement is alternate, rarely opposite. There are stipules. The flowers are collected in various inflorescences - raceme, head, umbrella, spike. The flowers are bisexual, with a double perianth. An irregularly shaped calyx of five fused sepals. The corolla is separate-petalled: the upper petal is called a sail, two side petals are called oars, and the two lower ones are fused - a boat. There are ten stamens, one is free, and the others are fused by stamen filaments into a tube. Pestle - one. The ovary of the pistil is surrounded by a stamen tube. The stamens and pistil are located inside the boat.
Legumes are insect-pollinated plants, some are self-pollinating (peas).
A characteristic feature of the family is the bean fruit. This is a multi-seeded fruit, opening from the top to the base. The seeds are attached to the valves. Seeds without endosperm.
Most legumes have nodules on their roots. The nodules contain nitrogen-fixing bacteria that are capable of using molecular atmospheric nitrogen and converting it into a form that can be absorbed by plants. All organs of legumes contain large amounts of protein. Legumes - food (peas, beans, soybeans), fodder (alfalfa, clover), melliferous (lupine, sweet clover) plants.
Nightshade family includes about 2500 species. Herbaceous plants, in tropical zones - shrubs and trees.
The leaves are simple, whole or dissected, without stipules. The leaf arrangement is regular. The flowers are solitary, often collected in an inflorescence - a raceme. The flowers are bisexual with a double perianth. A calyx of five fused sepals is retained by the fruit, sometimes completely enveloping the fruit (physalis). A corolla of five fused petals in the shape of a bell or funnel. There are five stamens, they grow into the corolla tube, the anthers cover the pistil style in the form of a cone. There is one pistil, formed by two carpels. The fruit is a berry, less often a drupe or capsule.
Poisonous alkaloids are formed in various organs of nightshades, so many of them are poisonous.
Family Asteraceae includes about 25,000 species. This is one of the largest plant families.
Most Asteraceae are herbs, both annual and perennial, and less often subshrubs. Shrubs, trees, and vines grow in tropical areas.
Leaves are simple, without stipules, entire or dissected. The leaf arrangement is often alternate, less often opposite or whorled. The leaves can be collected in a basal rosette. The vegetative organs of many Asteraceae species may contain milky or resin ducts. A characteristic feature of the family is the inflorescence basket. The baskets can be collected into more complex inflorescences - a corymb, a panicle, etc. The basket has an extended axis of the inflorescence, forming a bed. The bottom of the basket is surrounded by apical leaves, or involucre. There are numerous flowers on the base of the basket. Usually the flowers are bisexual, but can be unisexual, male or female, sometimes the flowers are asexual. Flowers in a basket can be the same in structure or different; usually the middle flowers differ from the edge ones. The calyx consists of five membranous sepals, which are usually modified into hairs. The hairs form a tuft, trailers or bristles. The crest grows with the fruit and turns into a fly.
Based on the type of fusion of the corolla petals, the following types of flowers are distinguished:
Tubular - the petals grow together into a tube, expanding upward. Flowers are bisexual, less often unisexual;
Reed - the tube of fused petals is short, there is a five-toothed bend in the form of a tongue. The flowers are bisexual;
Funnel-shaped - the corolla tube is long, curved, greatly expanded towards the top. The flowers are asexual and are located along the edge of the basket. Serve to attract insects.
There are five stamens. The bases of the stamen filaments grow to the corolla tube, the anthers grow together and surround the pistil style. There is one pistil, formed from two carpels. The fruit is an achene, usually with a tuft, but can also be without a tuft (sunflower). Seeds without endosperm.
The main families of the class Monocots (lily and cereals).
To the linear family includes about 1300 plant species. The vast majority of lilies are perennial herbs that have underground storage shoots: bulbs or rhizomes. Creepers and trees are less common.
The leaves are linear or lanceolate, with parallel arched veins. The leaf arrangement is alternate, opposite or whorled. The flowers are either single or collected in inflorescences - panicle, raceme, umbrella, spike. The flowers are bisexual with a simple corolla-shaped perianth. The perianth can be divided-leaved or fused-leaved. There are six stamens; the filaments can grow onto the perianth tube. There is one pistil, usually formed by three carpels. Several columns extend from the top of the ovary - according to the number of carpels. Insect-pollinated plants. The fruit is a capsule or berry.
Cereal family- one of the most species-rich families of plants in the monocot class. It includes about species.
Representatives of this family play a vital role in the formation of herbaceous vegetation of meadows, prairies, savannas, etc.
Cereals are perennial herbaceous plants with a fibrous root system. Woody representatives of cereals are beeches.
The stem of cereals - straw - is cylindrical with hollow internodes. The leaf arrangement is regular. The leaf consists of a cylindrical sheath and a narrow leaf blade. Cereals have intercalary growth. Branching in cereals takes place underground or above the soil surface - this is where the tillering zone is located: the bases of shoots with close nodes. The above-ground part of the cereals dies off annually, only the above-ground and above-ground parts of the plant remain alive. The flowers are collected in an inflorescence of spikelets. Individual ones form complex inflorescences - a panicle, a complex spike, etc. The spikelet consists of one to several flowers. On the main axis of the spikelet there are scale-like leaves, of which the lower two are called spikelets. The flowers are small, bisexual. Perianth membranes are located above the upper flower scales. There are usually three stamens. The stamen filaments are greatly elongated and carry the anthers out of the flower. One pistil with two feathery stigmas. The fruit is a grain. In the caryopsis, the perianth fuses with the seed coat, and the seed with the endosperm.
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S. V. Lazarevich
SYSTEMATICS
ANGIOSPERMS
Course of lectures
for students of biological specialties
agricultural universities
Gorki 2007
UDC 582.5/. 9 (075.8)
BBK 28.592.7 i 7
Approved by the methodological commission of the Faculty of Agronomy on 02/16/2007 and by the scientific and methodological council of the Belarusian State Agricultural Academy on 04/26/2007.
Lazarevich S. V.
L 17: Taxonomy of angiosperms. A course of lectures for students of biological specialties of agricultural universities. Gorki: EE "Belarusian State Agricultural Academy", 2007. 76 p.
The features of the Angiosperms department and its evolution are described. The classes and families of flowering plants that are of great economic importance and widespread in the natural phytocenoses of Belarus are characterized.
For students of biological specialties.
Table 2. Fig. 1. Bibliography 17.
Reviewers:
head Department of Biology, Doctor of Biology. Sciences A. M. Karabanov (EI “Mogilev State Pedagogical University named after A. Kuleshov”); Leading Researcher, Doctor of Biology. Sciences V.N. Prokhorov (GNU “Institute of Experimental Botany named after V.F. Kuprevich NAS of Belarus”).
UDC 582.5/. 9 (075.8)
BBK 28.592.7 i 7
ã S.V. Lazarevich, 2007
ã Educational institution
“Belarusian State
Agricultural Academy”, 2007
INTRODUCTION
The taxonomy of angiosperms is the oldest and most important part of botany. Its development is a unique reflection of the development of human culture. Having arisen from the initial differentiation of plants into edible and inedible, medicinal and poisonous, taxonomy rose to the level of theoretical generalizations of the main paths and directions of evolution of the plant world.
Currently, the goal of taxonomy is to describe and study the exceptional diversity of plants, to establish relationships between individual taxa of angiosperms and other divisions, as well as to identify patterns of their evolution.
The taxonomy of angiosperms has a direct connection with introduction, selection and genetics, plant growing, ecology and other sciences. Its theoretical provisions are directly related to the practical activities of man. They underlie the mobilization of plant resources for the benefit of humans, as well as the rational use of cultivated plants.
In connection with the constant formative process taking place in natural and artificial phytocenoses, as well as with the expansion of the ranges of the studied territories, taxonomy has prospects for further development.
When compiling this course of lectures, the qualification characteristics of graduates of biological specialties and the features of higher agricultural education were taken into account. Therefore, the main attention is paid to the key distinctive features of angiosperms and the directions of their evolution, as well as to the analysis of families whose representatives are widespread in the cultural flora and are of great economic importance in the Republic of Belarus.
When describing the volume of families, Russian and Latin names of plants growing in natural phytocenoses of Belarus, the “Key to Higher Plants of Belarus” and the multi-volume book “Plant Life” were taken as a basis. To deepen your knowledge of the families analyzed in the lecture course, you can use the literature listed at the end of each section.
DISTINGUISHING FEATURES OF ANGIOSPERMS
Angiosperms appeared on earth about 150 million years ago. They are thought to have evolved from early Mesozoic seed ferns, which, like gymnosperms, originated from Paleozoic seed ferns.
The similarity of the origin of angiosperms and gymnosperms from seed ferns, based on the similarity of sporogenesis and development of the male gametophyte in both departments, may indicate their parallel evolution and is not evidence of the origin of flowering plants from gymnosperms. Moreover, the transitional forms between gymnosperms and angiosperms are unknown to modern science.
Angiosperms represent the largest, most highly developed and at the same time the youngest branch of plant evolution. The number of angiosperm species is about 250 thousand, which exceeds the species diversity of all other higher plants combined. Angiosperms are the dominant plant division in the modern biosphere. Possessing high evolutionary plasticity, they have adapted to growing in various natural and climatic zones of our planet. This was facilitated by the emergence and development of a complex of aromorphoses and idioadaptations as factors of biological progress:
the emergence of a flower as an organ of seed reproduction;
significant reduction of female and especially male gametophytes;
the appearance of double fertilization;
development of polyploid endosperm of the seed after fertilization;
development of seeds inside the fruit and, as a result, their protection from unfavorable environmental factors by the fruit membranes;
significant development of the conducting system, the presence of vessels in the xylem and sieve tubes with companion cells in the phloem;
a wide variety of stems, roots and especially leaves;
stronger development of photoperiodism.
Due to differences in the paths and rates of plant evolution, which took place at different times and in different ecological-geographical zones of our planet, modern angiosperms exhibit an exceptionally diverse combination of evolutionarily ancient (primary) and evolutionarily young (secondary) characters, which is called heterobatmy (Table .1.1).
Table 1.1. Correlation of characteristics of flowering plants
| Item No. | Primary signs | Signs are secondary |
| Single flowers | Flowers are collected in inflorescences | |
| The number of flower members is large, indefinite | The number of flower members is small, defined | |
| The arrangement of the flower members is spiral | The arrangement of the flower members is circular | |
| Double perianth | Flower without perianth | |
| Separate corolla | Corolla interpetalous | |
| Actinomorphic flower | Flower zygomorphic | |
| Ovary superior | Ovary inferior | |
| Gynoecium apocarpous | Gynoecium coenocarpous | |
| Flowers bisexual | Unisexual flowers | |
| Cross pollination | Self-pollination | |
| Insect pollination | Wind pollination | |
| Monoeciousness | Dioecy | |
| Seed with endosperm | Seed without endosperm | |
| Seed with two cotyledons | Seed with one cotyledon | |
| Stem erect | Climbing stem | |
| Stem unbranched | Branched stem | |
| Vessels are poorly developed | The vessels are well developed | |
| Simple leaf | Leaf compound | |
| Evergreen leaves | Leaves falling | |
| Leaf arrangement is spiral | Leaf arrangement is opposite or whorled | |
| Reticulated venation | Venation parallel | |
| Autotrophic nutrition | Heterotrophic nutrition | |
| Woody perennials | Herbaceous annuals | |
| Land plants | aquatic plants |
Taking into account molecular genetic, cytological, histological-anatomical, morphological characteristics of vegetative and generative organs, ecological and phytogeographical characteristics of plants, as well as statistical and computer science methods is used to establish related relationships between individual taxa and is the basis for constructing modern phylogenetic systems for classifying angiosperms.
Literature: 3 (p. 7 – 14, 25, 26, 37, 38), 6 (p. 385 – 417), 14 (p. 252 – 255, 311–312).
CLASSIFICATION OF ANGIOSPERMS
The Angiospermae department got its name due to the fact that their seeds develop under the cover of the fruit shell. The second name - Flowering plants (Anthophyta), indicates that their organ of seed reproduction is a flower. Later, when it was proposed to name taxa taking into account the names of the most ancient typical representatives. Flowering plants are called the department Magnoliophyta. These three department names are used interchangeably, but the latter is preferred as it more closely matches modern botanical nomenclature.
The department Angiosperms, or Magnoliophytes, is divided into the class Dicotyledones, or Magnoliopsida, and the class Monocotyledones, or Liliopsida. Their main distinguishing features are presented in table. 2.2.
Table 2. 2. Distinctive features of the classes of angiosperms
| Item No. | Class Dicotyledons | Class Monocots |
| The root system is taproot. The cap and the epiblema have a common origin | The root system is fibrous. The cap and the epiblema have different origins | |
| Stems are woody or herbaceous. Herbaceous plants evolved from woody plants | The stems are often herbaceous. There are no primary woody plants | |
| Vascular-fibrous bundles are open. The presence of cambium contributes to secondary thickening of the stem | Vascular-fibrous bundles are closed. The absence of cambium excludes secondary thickening of the stem. | |
| Conducting bundles are arranged in a circle | Conductive bundles are arranged in a spiral | |
| Phloem usually with parenchyma | Phloem without parenchyma | |
| The bark and core of the stem are differentiated quite clearly | The bark and core of the stem are poorly differentiated | |
| The leaves are different in shape, often complex, and may have stipules. The petiole is usually clearly defined | The leaves are often simple, linear or lanceolate, often without stipules. Petiole is usually absent | |
| The leaf venation is pinnate or palmate. The ends of the veins are not closed. There are usually one to three leaf trails. | The leaf venation is parallel or arcuate. The ends of the veins are closed. The number of leaf marks is usually large | |
| FINAL TABLE. 2. 2. | ||
| Leaves usually without a vaginal base | Leaves usually have a vaginal base | |
| Flowers 5- or 4-membered, rarely 3-membered | Flowers are usually 3-membered, sometimes 2- or 4-membered | |
| The perianth is often double | The perianth is often simple | |
| Nectaries of different types, often are modified stamens, rarely septal | Nectaries are often septal, i.e. located on the septa of the ovary | |
| During the process of microsporogenesis, microspore shells are laid simultaneously (simultaneously) | During the process of microsporogenesis, microspore shells are laid down successively (sequentially) | |
| The shell of pollen grains is usually three-striated or of types derived from it | The shell of pollen grains is usually single-striated or of its derivative types. Most often single-pore | |
| The seed embryo usually has 2 cotyledons (sometimes 1, 3, 4). Cotyledons with 3 main vascular bundles | The seed embryo has 1 cotyledon. Cotyledons with 2 main vascular bundles | |
| Endosperm cellular (cellular) or nuclear (nuclear), rarely helobial (basal) | The endosperm of the seed is helobial or nuclear, very rarely cellular | |
| Cotyledons usually germinate aboveground | Cotyledons usually germinate underground |
The classes of angiosperms are divided into subclasses (Fig. 2.1).
Fig.2.1. Subclasses of dicotyledonous and monocotyledonous angiosperms
and their evolutionary connection.
In modern botany in the classroom Dicotyledons, or Magnoliopsids, There are 7 subclasses, 325 families, about 10,000 genera and about 180,000 species.
Subclass 1 – Magnoliids (Magnoliidae). They are closest to the original group of plants that gave rise to the angiosperms and include the primitive orders of dicotyledons, including Magnoliaceae, Laurelaceae and Nymphaeaceae.
Subclass 2 – Ranunculidae. They include Ranunculaceae and orders close to them. Probably descended from magnoliids.
Subclass 3 – Hamamelididae. They are believed to have evolved from magnoliids. They unite Nettle, Beech, Witch Hazel and other related orders.
Subclass 4 – Caryophyllidae. They originate from ranunculids. This includes the orders Clove, Buckwheat, etc.
Subclass 5 – Dilleniidae. Includes the orders Dillenium, Tea, Violet, etc. They originate from the ancient magnoliids.
Subclass 6 – Rosidae. They come from the Dilleniyids. These include the orders Pink, Legume, Rutaceae, Geraniaceae, etc.
Subclass 7 – Asteridae. They most likely descend from ancient rosids. Includes the orders Asteraceae, Campanaceaceae, Lamiaceae, Norichaceae, etc.
Class Monocots, or Liliopsids, divided into 3 subclasses, 65 families, 3000 genera and approximately 60,000 species.
Subclass 1 – Alismatidae. They originated from some ancient group of herbaceous magnoliids, close to modern nymphaeans. The subclass includes Chastukhova, Vodokrasov, Naiad and other orders.
Subclass 2 – Liliids (Liliidae). They are close in origin to alismatids. This includes the orders Liliaceae, Orchids, Bromeliads, Sedgeaceae, Poagrass, etc.
Subclass 3 – Arecidae. They have a common origin with the lilyids. These include Palmaceae, Cataceae, Pandanaceae and other orders.
Smaller than a subclass, the main taxonomic units are order, family, tribe, genus, section, series and species, which in turn can be subdivided into additional units, for example, subfamily, subgenus, subspecies. In agronomic practice and breeding work, categories are distinguished within a species: ecotype, variety, variety, hybrid, line.
Literature: 3 (p. 107–112), 6 (p. 372–380), 14 (p. 312–313).
Angiosperms are divided into two classes - dicotyledons and monocotyledons. Dicotyledons are characterized by: two cotyledons in the seed, open vascular bundles (with cambium), preservation of the main root throughout life (in individuals born from seeds), pinnate and reticulate venation of leaves, 5-4-2-membered type of flowers.
Monocots are characterized by opposite characters: one cotyledon per seed, closed vascular bundles (without cambium), early death of the main root and development of an adventitious root system, parallel or arcuate venation, three-membered type of flowers. Individual characteristics of one group can also be found in representatives of another group, so the entire set of characteristics is important.
Monocots (lat. Liliopsida, lat. Monocotyledones, English monocots) are a class of angiosperms, or flowering plants, the largest family of which is the Orchids, distinguished by extremely complex, beautiful flowers. In second place in terms of the number of species is the economically very important family Cereals.
The traditional Latin name for this group of plants is Monocotyledones, although more recently, for example in the Cronquist system, their official name is Liliopsida. Since monocots are a group of higher rank than family, the choice of name is not limited in any way. Article 16 of the ICBN allows both a descriptive name and a name derived from the type gender of the group.
The traditional name monocots, Monocotyledones or Monocotyledoneae, comes from the fact that the embryos of most members of the group have only one cotyledon, in contrast to dicots, which usually have two. From a diagnostic point of view, determining the number of cotyledons is neither an easily accessible method nor a reliable distinguishing characteristic of a plant. The distinction between monocots and dicotyledons was first used in plant taxonomy at the beginning of the 18th century by the English naturalist J. Ray.
However, monocots have more obvious distinctive features. The embryonic root usually soon stops growing and is replaced by adventitious roots. Stem vascular bundles are closed, scattered throughout the entire cross section of the stem; There is no cambium, so thickening of the stems like dicotyledons or gymnosperms is not observed. Stems rarely branch. The leaves are mostly stalk-embracing, always without stipules, usually narrow and arcuate.
Flowers are usually constructed according to the triple type: a perianth of two three-membered circles, stamens also 3 + 3, carpels 3, less often, instead of the number 3, the numbers 2 or 4 are observed in the flower.
Monocots are a monophyletic group that arose at the dawn of the history of the development of angiosperms. The oldest fossil plants that can be classified as monocots date back to the beginning of the Cretaceous period.
The APG II scientific classification system, developed by the APG (Angiosperm Phylogeny Group), identifies monocots as one of the two largest groups among the angiosperms. The second group is “eudicots”, according to established tradition, sometimes called “palaeodicots”. Among monocots, ten orders and two families are distinguished, which have not yet been definitively assigned to any of the orders. These orders are distributed as follows:
Major monocots
· Family Petrosaviaceae / en:Petrosaviaceae
· Order Acorales / en:Acorales
· Order Alismatales / en:Alismatales
· Order Asparagales / en:Asparagales
· Order Dioscoreales / en:Dioscoreales
· Order Liliales / en:Liliales
· Order Pandanales (Pandanales) / en:Pandanales Commelinids
· Family (Dasypogonaceae) / en:Dasypogonaceae
· Order Palmaceae (Arecales) / en:Arecales
· Order Commelinales (Commelinales) / en:Commelinales
· Order Poales / en:Poales
· Order Zingiberales / en:Zingiberales
A more traditional classification is the system of Cronquist (1981), according to which all monocots were divided into five subclasses with the following orders:
Alismatidae
Order Alismatales
· Order Hydrocharitales
Order Najadales
· Order Triuridales
Arecidae
· Order of Palm Trees (Arecales)
Order Cyclanthales
Order Pandanaceae (Pandanales)
· Order Arales
Commelinidae
Order Commelinales
Order Eriocaulales
· Order Restiales
· Order Juncales (Juncales)
Order Sedges (Cyperales)
Order Hydatellales
Order Cattails (Typhales)
Ginger (Zingiberidae)
Order Bromeliads (Bromeliales)
· Order Zingiberales
Liliidae
· Order Liliales
Order Orchidaceae (Orchidales)
The class Dicotyledons belongs to the department of Flowering (Anthophyta) or Angiosperms (Magnoliophyta, or Angiospermae) plants. This class is much more diverse and larger in volume than the second class from this department - Monocots (Monocotiledonae or Liliopsida). Of the total number of flowering plants, Dicotyledons account for about 80%.
The class Dicotyledons is characterized by the presence of the following characteristics that distinguish it from Monocots:
1. Embryo with two cotyledons.
2. The main root is well developed and persists throughout life, therefore the taproot (less often fibrous) root system predominates.
3. The stem is capable of secondary thickening due to the presence of cambium; conductive bundles are open.
4. The leaves are varied in shape and dissection, have palmate or pinnate veining, and the shape of the edge of the leaf blade can be different.
5. Flowers are acyclic, semicyclic and cyclic. The number of members of each circle is a multiple of 5, rarely 2, even less often 3.
The Dicotyledonous class includes about 200,000 species, 10,000 genera, and about 300 families (depending on the accepted classification). These are herbaceous and woody plants.
Since the 18th century, many botanists, both domestic and foreign, have been studying the taxonomy of flowering plants. All of them made an invaluable contribution to the modern construction of the phylogenetic (natural) system of flowering plants. However, there is still no generally accepted system for classifying angiosperms.
The most controversial question is which groups of angiosperms are closest to the ancient ancestral forms. In the systems of well-known botanists and phylogeneticists A. Engler and R. Wettstein, families with single-integumented and unintegued, inconspicuous, anemophilous flowers (willow, birch, etc.) are taken as the most primitive groups.
In more modern systems, families with well-developed polynomial, dioecious, entomophilous flowers, the so-called polycarpids (families Magnoliaceae, Ranunculaceae, etc.), are considered as a primitive group. Families with single-covered flowers are considered secondary simplified. Such systems are the systems of botanists N. A. Bush, A. A. Grossheim, A. L. Taxtadzhyan, Hutchinson (England), etc. One of the latest systems, which takes into account the largest number of characteristics, is the system of A. L. Takhtadzhyan ( 1970).
According to A.L. Takhtadzhyan, the Dicotyledonous class includes 7 subclasses: Magnoliidae, Ranunculidae, Hamamelididae, Caryophyllidae, Dilleniidae, Rosidae and Asteridae. Within each subclass, its families are combined into orders. The entire class Dicotyledons includes 71 orders. The former cover the most primitive families, the latter - phylogenetically more advanced.
Basic orders of the Dicotyledonous class:
Subclass Choripetalae: order Magnoliales, order Ranunculales, order Papaverales, order Capparales, order Rosales, order Fabales, order Malvales, order Geraniums (Geraniales), order Terebinthales, order Umbellales, order Centrospermae, order Polygonales, order Fagales.
Subclass Sympetalae: order Scrophulariales, order Cucurbitales, order Asterales.
