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The appearance of gymnosperms about 350 million years ago is a revolution in the plant kingdom. Indeed, for the reproduction of horsetails, lymphoids, ferns, which previously constituted the basis of the earth's vegetation cover, water was needed. That is, these plants could exist only near water bodies and in a mild, humid climate. But the climate changed, the area of the swamps decreased, vast arid areas began to appear, and clever nature came up with a method of reproduction that did not depend on the aquatic environment. The plants have seeds. They were not hidden in the fruit, but lay open, "bare", hence the name - gymnosperms. Cycads became one of the first groups of gymnosperms. Cycads are already in full bloom in the impending era of the dinosaurs. There were so many of them that the Mesozoic is sometimes called the "era of the cycads". The distribution areas of ancient cycads covered vast areas; their remains were found in Eurasia, including some areas of Siberia, up to the islands along the coast of the Arctic Ocean, as well as in Greenland; in Australia, Antarctica.
Such a wide distribution of cycads is due not only to the mild climate, but also to a new progressive method of reproduction. Plant propagation has so far been associated with water. Even after taking a step on land, horsetails, lymphoids, ancient ferns were very dependent on water due to the peculiarities of not only structure, but also reproduction. Their spores fell into the water or onto damp ground, and fertilization took place here. But about 350 million years ago, in the middle of the Carboniferous period, plants appear, in which the mode of reproduction is absolutely vanguard in comparison with all plant organisms that existed then. This is how David Attenborough describes this amazing new acquisition: “Cycads look like ferns with long, stiff feathery leaves. Some individuals form tiny primordial spores that can be carried by the wind. On others, the disputes are much larger. They do not fly off under the breeze, but remain attached to the parent plant. There, a kind of analogue of the thallus develops from them, a special kind of conical formation, inside of which the eggs are ultimately formed. A small spore flying in the wind - in other words, pollen - falls on the lump containing the eggs and germinates, but it is not formed by a flat thallus, which is no longer needed, but a long tubular proboscis, stretching into the female lump. This process continues for several months, but in the end, when the formation of the tube is completed, a spermatozoon is formed from the remnants of the pollen spore. This is the largest sperm cell in the entire animal and plant world, it is a ball covered with cilia, visible even with the naked eye. The ball moves slowly down the tube; Having reached the bottom, it falls into a drop of water released by the surrounding tissues of the cone, and, drawn by moving cilia, begins to swim in it, slowly rotating and repeating in miniature the journey of the male cell of its algae ancestors through the waters of the primitive ocean. Only a few days later it merges with the egg, and this is how the whole long process of fertilization ends. "
Having received the opportunity to dwell on land, the cycads, however, were not yet capable of long-distance travel, and although they spread widely, most of them remained tied to near-water spaces. The split of the huge Gondwana spread the continents for thousands of kilometers, protecting their uniqueness by the waters of the oceans washing the shores. Cycad species continued to live in isolation, survived, but for the most part became endemic, unique aborigines of their habitats. And even here, in their native lands, cycads were pushed aside by other plants.They often live on nutrient-poor sands, volcanic rocks, and not because they like such substrates, but because more progressive flowering plants do not pose serious competition here.
But this did not happen everywhere. In Japan, on the Ryukyu Islands, cycads form extensive thickets on the sea coasts. In Africa, cycads are found in the savannas, however, scattered, not continuous massifs; in the rain forests in northeastern Australia, the tallest of the cycads grows - Hope's lepidosamia (Lepidozamia hopei), reaching a height of 18–20 m; there are cycads both on the islands of the Indian Ocean and in the Amazon.
A little more than 100 species of these relics remained on Earth, and they are not at all similar to other, much more common, representatives of the gymnosperm class - conifers. In appearance, the cycad (Cycas) rather looks like a stocky, undersized palm tree. Yes, and Latin Cycas - rather a nomenclature incident, because it comes from the Greek kykas - "palm". The cycad has a short, thick, like a barrel, trunk, from which feathery leaves fan out. But if you happen to see an unfolding leaf, you will undoubtedly notice that at this moment it does not at all look like a palm leaf. A young leaf, covered with scales, is rolled up by a snail and looks a lot like ... Well, of course, ferns, and not by chance, because the primitive gymnosperms, which include cycads, descended from one of the "branches" of ancient ferns.
The most famous cycad drooping (Cycas revoluta) native to Japan, it is the only cycad grown in rooms. It grows very slowly. In the first years of life, only one new leaf appears per season; after 5–7 years of age, 2–3 leaves can unfold, but even an adult plant does not have more than 6–8 leaves annually. So even in adulthood, the cycad is not at all a giant. But he is a long-liver. It is believed that the age of five hundred years for this "the same age of dinosaurs" is not the limit.
The cycad leaf is slowly born, but it also lives for a long time, up to ten years. On one plant there are both young leaves, rising vertically, and middle-aged leaves fanning out to the sides, and falling, the oldest, but still living leaves. As the leaves die off, the height of the trunk increases, surrounded by armor of the remnants of leaf petioles. The trunk rarely branches, remaining columnar throughout its life. The most massive is its upper part, where the remains of the petioles are still thick and strong. Very old scales in the lower part of the trunk gradually die off, peel off and fall off. These remnants of the petioles not only protect the trunk from external influences, but are also a kind of external "skeleton". The fact is that the ancient cycads have not yet acquired powerful wood and are rather soft inside.
From the starch-rich core of the trunk, sago is obtained - a product similar to cereals. Starch-rich sago is an important foodstuff in many countries. Europeans learned about its existence in the era of the great geographical discoveries. At first, this product was brought by Marco Polo, but it was not obtained from the cycad, but from the starchy wood of the sago palms. The receipt of sago from the cycad became known only 450 years later, after James Cook's trip to Australia. The bark and outer layers of wood are removed from the trunk of the cycad. The core is cut into thin pieces, laid out on a mat and dried in the sun. When the cycad pieces are dry and crispy, they are ground into flour. The flour is sieved and washed many times, allowing the water to settle. The flour sediment is rolled with wooden fibers until cereal balls - sago are formed.
In the countries of East Asia, cycads have ritual significance. Their leaves, treated with a special composition, are used for funeral wreaths. Young juicy leaves are eaten.Wickerwork is made from old hard leaves, and the trunks are used as building material. The drooping cycad has long been used in oriental medicine. Its leaves are considered an anti-cancer agent and are used for hematomas. Preparations from the upper part of the trunk have an astringent and diuretic effect. It is believed that the inner starch-containing part of the trunk has a rejuvenating effect and helps to prolong life.
For us, the cycad is an excellent ornamental plant. And although it is not easy to maintain it, it is very popular. Small and stocky, but solid, solid, the cycad will give the room a sense of calmness, stability, and at the same time, with its exotic look, it will certainly add a "zest" to the interior. Keeping a cycad in your home is not easy. Like other gymnosperms, the cycad does not tolerate overdrying of the soil, but at the same time, in no case should it be flooded. And in fact, and in another case, it is extremely difficult to reanimate the cycad. Choose for a cycad, especially in winter, a place that is not too warm, but light, make sure that the stand or table on which the pot with the plant stands is not colder than room temperature. The cycad pot must have drainage. Never get carried away with a transplant, the cycad reacts painfully to this procedure. It can be transplanted no more than once every 3-4 years, while only slightly increasing the size of the container, by 2-3 cm in diameter. The substrate is prepared from turf, humus soil and sand in equal parts; if the mixture is very loose, add a little heavy, loamy earth. In the summer, watering is increased, but still not being too zealous, they make sure that the plant has enough light, but there are no burns from direct sunlight. You can put the cycad in the garden by placing it in partial shade.
