Plants - this is one of the most numerous and diverse forms of the kingdoms of wildlife. They give all living things the opportunity to breathe clean air, producing oxygen in the process of photosynthesis. They provide people and many animals with food and useful substances, decorate our life and make it beautiful. One of the most diverse departments of this wonderful kingdom is angiosperms. We’ll talk about them further.
Angiosperms: classification
This department includes two huge class classes:
- monocotyledonous;
- dicotyledonous.
Each of them is valuable not only for nature as a whole, but also for people in particular. After all, you just have to name at least several representatives who have monocotyledonous and dicotyledonous plants in their composition , examples will immediately confirm their enormous practical role in human life. So, they include:
- rye, wheat, oats, rice, buckwheat;
- rose hips, potatoes, tomatoes, eggplant and other crops;
- a huge number of herbs.
In general, the diversity of angiosperms is estimated at hundreds of thousands (about 350,000). At the same time, both monocotyledonous and dicotyledonous plants, examples of which can be cited for a very long time, have their own peculiarities in the structure, lifestyle, and vital processes. We will consider one of the classes - dicotyledons. We will figure out what characteristics these plants have, what applies to them and what their significance is.
Class families Dicotyledonous plants
The classification may be different. There are several options:
- Takhtadzhyan system;
- Reville system;
- APG;
- Dahlgren and Thorne;
- Kronquist.
Each took as a basis certain attributes and divided the whole class into orders, families, or subclasses. For ordinary people, a taxonomic unit such as a family is more familiar from the school bench. Therefore, we list these most common and numerous groups that make up the class in question.
- Moths, or Legumes. What dicotyledonous plants belong here? For example: peas , alfalfa, clover, peanuts, rank, acacia, astragalus, chickpeas, ceratonia and others.
- Rosaceae. Examples: rose hips, apple trees, pears, plums, strawberries, raspberries and others.
- Cruciferous, or Cabbage. A typical representative is cabbage. A dicotyledonous plant, an example of which can still be attributed to this family, is a radish. And also: mustard, colza, overbig, shepherd’s bag. Only about 3 thousand species.
- Complex flowers - include a large number of weeds, medicinal, fodder and food plants. Representatives: chamomile, dandelion, aster, cornflower, sunflower and others.
- Nightshade. A dicotyledonous plant, an example of which can be given here, is a tomato. And with it, and most of the important vegetable crops cultivated by humans (potatoes, eggplant and others). The very poisonous belladonna belongs to the same family.
Less well-known for our country are such families as:
- Bay;
- Crassulaceae;
- Purslane;
- Grape
- Myrtle;
- Pumpkin
- Begoniaceae;
- Walnut
- Willow;
- Umbrella
- Birch and others.
In fact, there are a lot of them, so listing everything is difficult. Let us now consider what common features all representatives of dicotyledons possess.
Structural Features of Dicotyledons
Like all higher plants, they have a stem, leaves, root, flower. If we are talking about woody forms, that is, the trunk and branches. In general, the structure of a dicotyledonous plant is no different from that of others. However, there are also features that allow one or another species to be attributed to this class.
These characteristic data are their distinctive feature precisely from monocotyledonous ones, because all Tsvetkovye are similar in basic parts, it is difficult to correctly correlate species by taxa, if you do not know any special signs.
Key features
So, these are the following parameters:
- Leaf venation in most cases mesh.
- The root system is the pivotal, most often perennial.
- The formula for the structure of the flower: H 4 L 4 T 2 + 4 P 1 . In general, the number of parts must be a multiple of either 4 or 5.
- A layer of cambium is located between the xylem and the phloem, so many forms have a lignified stem.
- The leaf blade is often strongly dissected.
These signs of dicotyledonous plants do not at all mean that all representatives are arranged only this way and not otherwise. As elsewhere, there are also exceptions, some combinations.
However, the most important feature is that the seeds of dicotyledonous plants have two cotyledons located opposite each other. Using peanuts or beans as an example, this can be clearly seen with the naked eye. This sign is characteristic of all representatives of dicotyledons without exception. It was for him that they got their name.
Dicotyledonous plants: examples, photo
We have already given many examples of different representatives of this class. However, they mainly focused on those species that grow in our country. Below you can see photos of some foreign endemic to which the climatic conditions of Russia are not at all suitable. This is for example:
- laurel;
- royal delonix;
- sundew;
- Sarracenia
- nepentes;
- teak;
- black and mahogany and others.
The photo shows that they all have beautiful and brightly colored corollas. In general, almost all dicotyledons have spectacular flowers. However, there are exceptions among weeds.
Interesting Magnolia. Each species is a dicotyledonous plant. An example of a representative of this family is magnolia star. Very beautiful and fragrant plant of the East. Unusual and romantic legends compose about him. Magnolias are part of the culture of many southern countries.
Spicy plants
Dicotyledonous plants include representatives of the most fragrant, fragrant species - spicy. For example, such as:
- cinnamon tree;
- laurel;
- coriander;
- caraway;
- anise;
- dill;
- parsley;
- allspice and others.
Of course, their role in the food industry is great. Indeed, in addition to the direct purpose - to improve the taste of prepared dishes and give them a special flavor, they are also used as dosage forms.
Umbrella
The class Dicotyledonous plants includes in its composition such a family as Umbrella, or Celery. Their main distinguishing feature is the characteristic inflorescence in the form of an umbrella. Small flowers collected in bunches of pale, rarely bright colors. However, what really sets them apart is the smell. All representatives contain a large amount of essential oils, tannins, alkaloids. Therefore, the fragrance of Umbrellas is spread far in the district in the area where they grow.
The representatives are as follows:
- coriander;
- carrot;
- azhgon;
- celery;
- fennel;
- parsnip;
- milestone poisonous ;
- hemlock;
- hogweed;
- hairworm;
- astrantia;
- feverweed;
- dream and others.
There are both poisonous and very useful plants for humans. Also, many are decorative.
Rosaceae
The most popular representative is rose hips or roses. This dicotyledonous plant, an example of which is always given, barely comes the talk of the Rosaceae family. But, of course, not only it is part of this delicious taxon. Why delicious? Because it is here that includes:
- raspberries;
- cherry;
- plum;
- quince;
- figs;
- Apple tree;
- irga;
- Rowan;
- apricot;
- cherries;
- almonds and other very tasty representatives.
In addition to taste, they are also valuable owners of vitamins, beneficial macro- and microelements and various compounds.
Among the representatives there are also usual grassy forms: common cinquefoil, nettle, hemp, gravel and others.
Compound flowers
This family includes herbaceous, rarely ligneous perennials. There are so many representatives that they are found almost all over the globe. Compositae are present in the tropics and in the Arctic. This is the largest and most diverse group of all dicotyledons.
There are hundreds of examples. We will name the most famous, so that it becomes clear what specific plants are in question:
- aster;
- sunflower;
- dandelion;
- dahlia;
- chicory;
- marigold;
- chamomile;
- daisy;
- sickle;
- ragweed and others.
The most interesting representatives are:
- petioles sclesia;
- brachylene merana.
They are interesting in that they are very powerful trees up to 20/40 meters high respectively. Skalesia has very fragrant yellow flowers collected on the tops of branches. Many of these trees form whole forests on the Galapagos Islands.
Brahilena Merana grows in South Africa and Madagascar. Up to 40 meters high. The flowers are very large, collected in panicles on the tops of the branches.