Orchid representatives are spread all over the globe, where only heat is sufficient for them. According to the latest information, there are about 15,000 species of orchids, and as new studies in tropical countries increase. Most - and moreover, the most beautiful - orchids are in the tropical zone, and as they approach the temperate zone, their number decreases. In wed Europe and Russia, most orchids are found in meadows and mountainous areas.
Regarding lifestyle, orchids are divided into three groups. The first group includes saprophytes, that is, orchids living on substrates, which are the product of the decomposition of other plants. The group does not count, because it does not belong to culture. The second group consists of epiphytic orchids growing on other living plants - trees. These are the inhabitants of predominantly warm, humid tropics. Especially rich in orchids in the tropical America. The life of orchids in these areas is mainly due to the high humidity of the air, at least for a long period of the year. In these places, orchids usually grow in the crowns of tall trees of thick forests, rushing to the light, often in association with bromeliads, ferns and other epiphytes. Then, orchids are found along the edges of forests on low bushes singly and on slightly visible trees. Their roots, looking for supports, cling to the crust of trees, but do not penetrate inside the tissues of the tree. Thus, these orchids are epiphytes, and not parasites at all, as it may seem at first sight. They feed on their orchids from rotten leaves of virgin forest trees, from the debris of the animal world living in these forests and from the dust and mineral particles that come to them, falling to their roots, with very frequent tropics, thunderstorms here. The spongy outer coat of roots helps the orchids growing here to process large amounts of water. This is also facilitated by short straight air roots, available in different genera of orchids.
The third group consists of terrestrial orchids living on the soil surface and found in meadows, swamps, mountainous slopes and humus soil of shady forests. The jagged branched roots of these orchids extract nutrients from the soil, like other plants. Such terrestrial orchids are found in Australia, South Africa, in moderately warm parts of North and South America, as well as in Europe.
Applying to local climatic conditions, many genera of orchids develop overground, more or less pronounced tubers or have strongly developed leaves. The very shape of leaves of orchids is extremely diverse. Most of their leaves are soft, but there are many orchids and hard skin-like leaves.
Orchids in their structure are divided into two main groups: monopodial (nonliving stem) and sympodial (branched) structure.
The representative of the monopodial group with one unramified stem can be the genus Vanda. Branched orchids form the sympodial group.