The real "green sources" of water are numerous cactuses Mexican plateau. Here there are over 500 species. Cacti, some types of which are known to us as houseplants, reach extraordinary sizes and amaze travelers a variety of shapes and sizes. Familiar echinoid cacti here are kind of huge spiny balls height of over 1,5 m and 2-2,5 m in girth. Even from a distance you can see some big poles. It is cactus - Cereus. They reach a height of 20 m, a thickness of 1,5 m and have a great many thorns. The name "cereus" means "candle". And this is so: the dried Cereus very good and brightly lit. Travelers have long used them as a kind of torches that illuminate them the way at night.

Cacti, some types of which are known to us as houseplants, reach extraordinary sizes and amaze travelers a variety of shapes and sizes

Cacti are a very great benefit to the parched highlands of Mexico. Cacti do not only help to relieve thirst, and hunger. In some species Cereus fruits for flavor reminiscent of strawberries, gooseberries or orange. From the sweet-sour pulp tight cacti make compotes. Some species of cacti locals use as a medicine. Cacti and processed livestock feed. True, this process is necessary to plant stems blowtorch, since no knife does not cut the rough solids. Mexicans use cacti and as a building material.

It is believed that evolutionary cactus stood out about 30-40 million years ago, when South America and Africa were already significantly spaced apart by tectonic processes, but North America has not yet been connected to the South. Although fossil cacti today is not found, it is believed that they appeared in South America, and more recently, 5-10 million years ago, spread to the northern continent.

Cactus is a plant of the New World, that is, come from South and North America, and the West Indies. They are found, in addition to America, and in Africa, Madagascar and Sri Lanka, which is believed he was entered migratory birds.

Distinguishing features cacti are a specialized organ called the areola (areole) and it is a modified axillary buds with bud scales, transformed into hair and/or prickles. Another distinctive feature of cacti is a special structure of the flower and the fruit, when a substantial part of the flower and the fruit is, in fact, stem tissue. Cactus flowers and fruits are almost always bear the areola or in the form of rough hairs, that is the kidney, and the kidney usually belong to the stem, not the fetus.

Cacti come in very different shapes and sizes. There among the cactus bushes with conventional developed leaves - genus Pereskia - and low deciduous trees - genus Pereskiopsis. There are also a variety of epiphytic plants rainforest - Disocactus childbirth, Epiphyllum, Hatiora, Hylocereus, Selenicereus, Rhipsalis.