by Peter Lapshin
|CULTIVAR / КУЛЬТИВАР|
e-Magazine about exotic forms of Cactaceae
ENGLISH / RUS-(Win1251)
That such a cacti
This - hillock or Clotted weight or tuber surprising density, and it combines a variety of forms especially melons and Bur, combining both in one body, creation in the form of haystacks. Gerard, "Catalog of Plants, 1596
This question can be answered as follows: cactus - it is a plant belonging to the family Cactaceae. But in order to become the meaning of this definition, be aware that such a family, and that such cactaceous. Speaking figuratively, botanical family is like a human family in its meaning, which implies the existence of consanguinity. After all, both for humans and plants that word is a symbol group of individuals united by common origin, and endowed with some features of a family resemblance. Features of family resemblance cacti find difficult because of the three thousand members of this extensive family, there inexhaustible variety. There are giant cacti, reaching 18-20 m height, and there are cacti-dwarfs 3 cm in width and height of 1.5 cm Different not only in size but also the form of stalks, structure and color of flowers, their living conditions, the rate of growth.
Let's see ...
Here among Argentine gilei (wet evergreen forests) shake its proud crown high slender tree - Pereskiya. Between its large leaves rozoveyut brush small fragrant flowers ...
Here in the tropical forests of Brazil are hanging from the trees, strange plants, similar to the matted green hair, this epiphytic cactus Rhipsalis ...
Here is the rock Texas desert stretches impassable stunted brushwood thistly Echinocereus gray, all besprent large ruby flowers ...
Here is a powerful ribbed columns stand in the foothills of Arizona a lot of meter giants Carnegie, which declared the birthplace of the reserve ...
Here in Mexico savannah grasses hid a little uneven ball Mammillaria. The long hooked thorns growing from each stem tubercles of green, surrounded a wreath of tiny delicate flowers ...
It would seem, well, that may be common between them? And although their affiliation to the same family show signs of a family resemblance. Such signs of modern cacti-sciense has five. To be called cactus, plant, first, must be many years of succulents, secondly, to belong to a class of bipartite, and thirdly, to have a body called the areola, in the fourth, ovary fetus should be lower in the fifth, the fetus should be a berry.
On each of these five conditions is to talk in detail.
1. Perennial plant succulent - in the first definition of the word does not require an explanation: apparently, everyone knows that the plants living in contrast to annual plant for several years, are called perennials. As for the word "succulent", the so-called plant, which can store water in their tissues to help them carry drought.
False take the word "cactus" and "succulent" synonymous. This, unfortunately, quite common mistakes can be avoided if remember that each cactus - succulent, but not every succulent - cactus.
Succulent plants are found among the many botanical families - Euphorbiaceae, Crassulaceae, Liliaceae, etc. An example is the well-known Aloe arborescence of the lily family, which often occurs in many familiar rooms and under the wrong name of "one hundred plants."
2. Of belonging to the class of Dicotyledons could write a long chapter that goes far beyond this book, but for an amateur practically important, only two signs, both easy to remember: first, the seeds of these plants and their shoots have two cotyledons, and secondly, a dicotyledon cambium - layer of the most actively dividing cells, as a result of division by increasing the diameter of the growing stem, located in the correct form of a closed ring. This ring of cambium makes it possible to vaccinate a cactus on the other hand, poorly growing on strongly growing.
3. The presence of a cactus areol - special, one only cacti inherent authority. From the perspective of an amateur, this is the sign of belonging to the family Cactaceae are of particular interest and is the most important. Learning to distinguish from other cacti succulents on the presence or absence areol it is very easy, it is only fully understand what constitutes this interesting body that everyone has a cactus on his stem from a very early age, from about two weeks before the end of life.
If you compare cactus with deciduous plants, one can say that the areola cactus axillary line with the escape and kidney-leaved plants, that is, in fact, this is not one but two bodies, intimately connected and are one of a kind. (The interest that one group of Cactaceae, namely a Mammillaria, both of areoly separated and located at the stem apart: the first - in the sinus between the papilla, or protuberance, and the second - on its tip.)
Tops and bottoms of each areoly are strictly demarcated, entirely different functions. On top of that can be compared with the axillary kidney-leaved plants, there are buds, and a new increase in branching species. The lower part, corresponding to the escape, gives prickles, which are among the cactus can be easily separated from the stalk: thorn cactus - an independent body, not the growth of epidermis, such as spikes in milk. If the last such spike off, it will strip the skin - it makes it a whole.
Top of each areoly - a potential point of growth, and in case of removal of or damage to apical growth points of areol to stem, and often several at the same time assume its functions and provide a new growth, even among species, and no branching is not give children under normal conditions.
But sometimes the joy and surprise cacti fans with interesting and happens areoly mysterious thing: without any damage to apical growth points areoly few are beginning to grow quite the same way. At the stem appear as though a few tops, and they all grow independently of each other. The fact that this happens fantasticality and unusual forms exceeds the richest imaginations: in the cactus, have taken the wrong, so-called rock form, you can see the shapes of animals, birds and humans. Why there is this phenomenon, scientists still do not know the cause of his man and not learned.
If growing areoly scattered across the surface of the stalk, form of cactus called monstrose, that is terrible, but if they are located in a row resulting from their growth ridge is called cristata form (from the Latin crista - Bird comb or crest on the helmet ).
4. Lower ovary suggests that the portion of the cactus flower, from which the fetus will develop after fertilization, is located below the petals. Strawberries, in which the fetus is formed above the flower petals, can serve as an example of the top buttons. An example of the same plant with the lower ovary is cucumber. Every one of us happened to find the dried petals of a flower, preserved at the upper end of the young cucumber. The same phenomenon is observed and cacti: dried petals are sometimes stored in the fruit is fully mature.
5. Cactus fruit - berries. For a clear understanding of the latter should be, perhaps, agree that the concept of botanical berries are often not the same as the domestic value of the word. The hostess, carrying home a bag of cherries, says the friend: "You bought berries jam." And she, of course, look at you with surprise, if you ask her a dish of chopped watermelons, saying: "Skushayte piece of fruit!"
But the watermelon, as well as a tomato - is this berry, while the cherry fruit - no.
Cactus fruit, whether the size of a large discharging, or with tiny currants, all berries are typical: they are small seeds inside in the flesh, done in the skin. The size of the berries, color, juiciness, taste, the surface is smooth or covered with hairs, and thorns, are quite different from cacti belonging to different groups. Yes, and all of the cactus - the roots, stem, thorns, flowers and seeds is a great diversity. Listed five features are limited to features of "family resemblance", indicating the plants belonging to one family Cactaceae.
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