Each taxon of plants has its own characteristic features that distinguish it from the rest. Why is it impossible to see the flowers and taste the pine fruits? Why did the gymnosperms get such a name? Briefly and as clearly as possible we will answer these questions in our article.
Why gymnosperms got such a name: answer
These plants called gymnosperms the famous botanist Andrei Nikolaevich Beketov. Being the founder of the geography of vegetation in Russia, he wrote the first textbook on taxonomy. The sign underlying this name is the peculiarity 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 walls of the ovary.
Structural features
The life forms of these plants are represented by shrubs or trees, since a lateral educational tissue , the cambium, is formed in their stems. Gymnosperms evolved from higher spores. However, the fertilization process in them no longer depends on water, which is a progressive feature of the structure. Leaves of gymnosperms are called needles. They are needle-shaped, which reduces the surface from which water evaporates.
Why Gymnosperms got such a name also explains the structure of the ovary itself. It is a flake that is not at all capable of covering the embryo from cold and drought.
Do gymnosperms have fruits?
Many people think that cones are the fruits of gymnosperms. But this opinion is erroneous. The fact is that 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 sex cells - gametes.
The pollination process in gymnosperms occurs with the help of wind. So from male cones sperm end up in female ones, where fertilization and seed formation takes place. When the latter ripen, the cone flakes open. This happens only after 18 months. During this period, you can use the naked eye to look at seeds that lie directly on the scales. That is why gymnosperms got such a name. Thus, cones are modified shoots that perform the function of sexual reproduction.
In winter and summer ...
The children's mystery about the Christmas tree has been known to everyone since childhood. Most gymnosperms do not really drop foliage for the winter. Why? Gymnosperms received this name by the type of structure of the generative organs. But their ability to remain evergreen is associated with the vegetative: leaves and stem. The former, due to their shape and small surface, protect plants from excessive transpiration.
In winter, stomata are sealed with resin, due to which evaporation practically stops during this period. Protection is complemented by the fact that the needles are coated with cuticles. But this does not mean that gymnosperms do not change foliage at all. Needles can live up to 7 years, after which they die and are replaced by new ones. The exception is only larch. This plant changes its outfit every season.
Classification
Despite a number of common features, several classes are distinguished in this section. 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.
The class of Oppressive belongs to the amazing velvichia. This is a plant with the largest leaves, reaching several meters in length. They never fall. At the same time, the trunk itself, which is almost completely in the ground, is not visible. Velvichiya grows in the desert, where a strong wind constantly blows. He tears the leaves along, so they resemble a ball of snakes.
But the representatives of the class Sagovnikovye can be confused 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 the Sagovnikovy fall, the petioles remain on the stem.
The next class is represented by a single species - the bilobate ginkgo. This plant is endemic to China and Japan. Ginkgo reaches a height of 30 meters, and the trunk diameter is three and has a spreading crown. Its leaves resemble a fan with a recess in the middle. Translated from Japanese, the name of this plant means "duck legs", which also corresponds to their shape. In autumn, the leaves become bright red, and then fall off. In countries where ginkgo grows, they are considered sacred plants and are protected by law.
So, we examined why Gymnosperms got such a name. The reason for this is the location of seeds on the scales of the generative organs. They are not protected by the walls of the ovary and lie there naked, open. The characteristic features of these plants are the absence of flowers and fruits, vessels in the wood. Pollination in gymnosperms occurs with the help of wind, and the leaves are called needles.