Each plant taxon has its own characteristicfeatures that distinguish it from the rest. Why is it impossible to see flowers and try the fruits of pine? Why did the Tomeranians get this name? We will answer these questions briefly and as clearly as possible in our article.
Why the gymnasts received such a name: the answer
Голосеменными эти растения назвал известный botanist Andrei Nikolaevich Beketov. Being the founder of the geography of vegetation in Russia, he wrote the first systematics textbook. A sign underlying this name is a feature of the location of the seeds. They are located on the generative organs openly, "holo". Unlike flowering plants, in which the seeds are reliably protected by the ovary walls.
Features of the structure
The life forms of these plants are represented.shrubs or trees, because in their stems a lateral educational fabric is formed - cambium. Gymnastics are descended from the highest spore. However, the fertilization process in them is no longer dependent on water, which is a progressive feature of the structure. The leaves of gymnosperms are called needles. They have a needle shape, which reduces the surface from which water evaporates.
Why the Tomeranians received such a name also explains the structure of the ovary itself. It is a scale, which is not able to cover the embryo from the cold and drought.
Does the Gymnos are fruitful?
Many people think that cones are fruitgymnosperms. But this opinion is erroneous. The fact is that the fruits are formed only after the development of flowers. In plants that are representatives of this department, such generative organs are absent. They are represented by female and male cones, in which there are germ cells - gametes.
The process of pollination in the gymnasts occurs whenwind aid. So from the male cones sperm fall into the female, where fertilization and seed formation occurs. When the latter ripen, the scales of the cone open. This happens only after 18 months. During this period, you can see with the naked eye the seeds that lie directly on the scales. That is why gymnosperms received such a name. Thus, the cones are modified shoots that perform the function of sexual reproduction.
In winter and summer ...
Children's mystery about the Christmas tree is known to all even withchildhood. Most gymnasts do not really drop foliage for the winter. Why? The gymnosperms were named after the structure of the generative organs. But their ability to remain evergreen is associated with vegetative: leaves and stem. The first, due to their shape and small surface, protect plants from excessive transpiration.
In winter, the stomata are sealed with resin.what during this period evaporation practically stops. Protection is complemented by the fact that the needles are covered with a cuticle. But this does not mean that the Gymnastics does not change the foliage at all. The needles can live up to 7 years, after which they die and are replaced by new ones. The only exception is larch. This plant changes its outfit every season.
Classification
Despite a number of common signs, in this departmentthere are several classes. The most numerous of them are Conifers. Spruce, pine, fir, cypress, yew, cedar, larch are typical representatives of the class. They got their name by the type of leaves - needles.
Velvichiya belongs to the class Gnetovyeamazing. This plant with the largest leaves, reaching several meters in length. They never fall off. At the same time, the very trunk, which is almost completely located in the ground, is not visible. Velvichiya grows in the desert, where a strong wind is constantly blowing. He tears the leaves along, so they resemble a ball of snakes.
But representatives of the class Sagovnikovye canconfuse with a palm tree. Their stem does not branch. It is characterized by the presence of a developed core and weak wood. When the leaves of Sagovnikovy fall, the stalks remain on the stem.
The next class is represented by a single species -bilobed ginkgo. This plant is endemic to China and Japan. Ginkgo reaches a height of 30 meters, and the diameter of the trunk - three and has a spreading crown. Its leaves resemble a fan with a notch in the middle. Translated from Japanese, the name of this plant means "duck legs", which also corresponds to their form. In autumn, the leaves turn bright red and then fall. In countries where ginkgo grows, they are considered sacred plants and protected by law.
So, we looked at why the Gymnasticsgot this name. The reason for this is the location of the seeds on the scales of the generative organs. They are not protected by the ovary walls and lie there barely, openly. The characteristic features of these plants are the absence of flowers and fruits, vessels in the wood. Pollination in the gymnasts occurs with the help of the wind, and the leaves are called needles.
