It will be about one of the largest families among dicotyledonous plants - aster (Asteraceae). Without noticing it, we encounter its representatives almost every day - at home, in cooking, and just on the street. Flowers of the Astrov family are perhaps the most common in our flowerbeds and gardens, and not a single kitchen can do without sunflower oil.
Aster family: general description
The family includes a very large number of genera, it is difficult to name the exact number, it ranges from 1100 to 1300, and species more than 20, 000. Most of the plants are pollinated by insects. The distribution area is quite wide, representatives of this family are found in all climatic zones: from hot and humid tropics to the cold tundra, high in the mountains and on the coast of the seas. They grow on fertile chernozems and in the sands of deserts. A large number of species provided astrovas with widespread economic use in human life.
A distinctive feature of all plants that includes the Astrov family is a complex inflorescence - a basket that consists of many small and inconspicuous flowers, but together they make up a very impressive picture.
Flower structure
The name of the inflorescence, as it were, speaks for itself: a basket, that is, a certain capacity in which something is folded. Capacity - this is an expanded peduncle at the end, it can be flat, convex or concave. Just on it and numerous small flowers are located. And all around it is surrounded by one or more rows of bracts. All flowers of the family are divided into five types:
- Tubular, most often hermaphroditic and much less likely unisexual. They have the shape of a tube that expands at the end or has a limb.
- False-lingual flowers - they are formed as a result of the fusion of three petals and have the same number of cloves located on the upper edge.
- Reed - the corolla has the shape of a shortened tube, from which the petals, fused together. As a rule, they have five stamens and one pistil.
- Funnel - flowers of an asymmetric shape, asexual, a corolla in the form of a long tube greatly expanded at the end (funnel).
- Two-lipped flowers - the corolla tube is quite long, and two tongues (lips) are unbent from it. Can be bisexual or same-sex.
If we take the same sunflower as an example, then we are all used to perceiving it as a separate magnificent and beautiful flower. And this is absolutely wrong from the point of view of botany. Since in reality it is an inflorescence that contains more than 1000 individual small flowers (tubular), and the wide and bright petals of orange or yellow are reed flowers. Amazingly complex and delicate organization, thought out by nature to the smallest detail.
Representatives of the family have the following flower formula:
* Ca (0, intergrown) Co (5) A (5) G (2).
It is characteristic of the entire family of asters. The flower formula is deciphered as follows: the flowers are bisexual, have several planes of symmetry, a cup, a corolla of five petals, 5 stamens, two pestles, an ovary above them.
Leaf and root structure
The structure of leaves can only be said in general terms, since this is a fairly large group of plants, represented by various life forms. Sunflower, burdock, thistle, asters and zinnias, Jerusalem artichoke, treelike forms, yarrow, gerberas and many other species - all this family is aster. A general characteristic is that the arrangement of the leaves is usually the next, but may be the opposite. Dimensions, and even more form, vary in a very wide range from a few millimeters to 2-3 meters. Venation among members of the family is most often cirrus. The leaves may be pubescent, the severity is different, many plants have spines.
The root is quite well developed and in most plants has a pivotal structure (a well-developed main root and many subordinate). For example, it is enough to recall a typical representative of the family - dandelion officinalis, many are familiar with it and its root system. There may be modifications with thickenings resembling a tuber, such as burdock.
What are the fruits of plants in the aster family?
Asters (Asteraceae) have a fruit achene. It is dry, the seed contains one. Pericarp is leathery and does not burst when ripe. The formation on the achene of various hairs, protrusions, peculiar hooks is widespread, which in turn contribute to the spread of seeds in the wind (dandelion, wormwood), with animals or on people's clothes (succession, burdock).
Life form of asteraceae
Life forms are presented almost in full, and this is primarily due to the huge distribution area, but nevertheless aster (compound flowers) are mainly herbaceous plants (annual or perennial). Sizes vary widely - from very tiny representatives to giants several meters high.
Many species are shrubs or shrubs of fairly impressive size (up to 5-8 meters in height). For example, the marsh melampodium is home to the moist, swampy forests of Louisiana in the United States.
The aster family also has representatives among trees, though they are all inhabitants of the southern regions. For example, skalesia in the Galapagos Islands, which can reach 20 meters in height, but it is endemic, and it is no longer found in any corner of the planet. Or plants of the genus Brahilen from South Africa. Giant trees that have sufficiently strong wood, resistant to decay, for which they are highly valued.
In the alpine meadows of New Zealand, haatsia cannabis forms entire thickets. This is a tree-like form that covers a fairly large area with a thick carpet up to half a meter (one plant can grow up to two meters in diameter).
They are found amongst compound vines (mikaniya, mutisiya), succulents and even such a rare life form as tumbleweed (cornflower spreading, dwarf asteriskus).
Traditionally, the entire family of asters is divided into two subfamilies: tubular and reed.
Aster subfamily (tubular)
The vast majority of colors are tubular. This group of plants has more than a thousand genera and more than twenty tribes (a taxonomic rank in botany, which by value is lower than the family, but higher than the genus). For example, the most famous are asters, calendula, sunflower, umbilical, marigold and others.
The subfamily chicory (or lettuce)
Their second name is reed, in contrast to the previous family, contains only seven tribes, and the number of genera is about two hundred - this is a small part of the total number of plants belonging to the aster family. Representatives of chicory flowers grow on almost all continents, in our country the most famous species is ordinary chicory, remarkable for its bright blue flowers and spread like a weed. Nevertheless, the plant is a good honey plant, and in cooking, the root is used to make coffee.
Aster family: nutritional value
The use of plants of this family in cooking has been popular for a long time, the most famous example is oilseed sunflower. His homeland is North America. He successfully acclimatized in our area, now sunflower is grown on an industrial scale. The main product from it is, of course, sunflower oil. But in addition to this, seeds, salomas (solid fat used to make margarine and soap) are obtained, and production waste is used as animal feed.
Another bright and edible, but, unfortunately, we do not have a growing representative of the family - artichoke (pictured). Traditionally, it is considered a vegetable, but in fact it is an unopened bud. As a stand-alone dish or side dish, it is widely distributed in the Mediterranean countries and in America.
Jerusalem artichoke, cultivated not only as a food, but also as a technical and feed plant, is famous for its taste.
