A flower is a rather complex and naturally unique organ of angiosperms. Its main function is the sexual reproduction of the body. Despite the fact that the structure of the flower has some common features, for each group of plants it is individual and is considered a characteristic taxonomic trait.
Flower, its functions and characteristics . Before considering the structure of the flower, it is necessary to find out what this generative organ is. A flower is nothing more than a shortened shoot, while the petals, pistils, stamens and sepals are mutated leaves.
Flowers of different representatives of the flora have a wide variety of characteristics. For example, depending on the method of pollination, they can have different colors and shapes, as well as additional parts, such as nectaries. The same can be said about their sizes - the smallest duckweed flower has a diameter of 1 mm, and the flower in some topical plants reaches a meter diameter.
The general structure of the flower . It is customary to divide its structure into three main parts:
- Stem part - consists of their pedicels and receptacle.
- Leaf part - here include petals and sepals.
- The generative part is pistils and stamens.
The flower is located at the top of the shoot, both the main and the side. The stem of the shoot smoothly passes into the peduncle (for sessile flowers, this part is either greatly shortened or completely absent). It expands upward, forming the so-called receptacle - it is to him that all the other parts of the flower are attached. It can be convex, concave, elongated or flat - this is also an important taxonomic trait.
Flower: perianth structure . Perianth is called the sterile part of the flower. Its main function is to protect generative parts. In addition, the method of pollination of the plant depends on the shape and structure of the perianth .
Perianth is divided into:
- Simple - all of its leaves are the same (for example, if you look at the structure of a tulip flower, you can see that its perianth is simple).
- Double - perianth elements form a cup and a nimbus.
The cup consists of individual sepals - they can be free or grow together.
The corolla is a collection of petals. As a rule, they are the most noticeable part of the flower. They can grow together or remain free. In some representatives of the plant world, for example, in legumes or orchids, corollas are characterized by a rather original structure. Petals can have specialized epidermal cells that secrete essential oils - this is how aroma is created.
The main functions of the corolla are protection against high temperatures during the day, protection from overcooling at night, protection from sunlight, as well as the attraction of pollinating insects.
Flower structure: generative part . The generative part of the flower is represented by androecium (a set of stamens) and gynoecium (a set of pistils).
Stamens are the site of formation and maturation of plant pollen. Their number can vary from one to several hundred. These flower elements can grow together, or remain free. The stamen is attached to the receptacle with a thin stamen thread, on which the anther is located on top. In turn, the anther is divided into two halves, in each of which there are two nests, where microspores are contained.
Pestle is one of the main organs of the flower. It consists of carpels fused together. Pestle can be divided into ovary (lower part, where the egg is kept), column and stigma (part, which takes pollen).
The structure of the flower can be completely different. But it is worth noting that the quantity, form, presence and other trifles in the structure of each of its individual parts are actually important taxonomic features that are used in modern taxonomy.