OUR ORCHIDS FRIENDS
CLASSIFICATION OF ORCHIDS
Although orchids belong to a single large botanical family, that ofOrchidaceae, include a large number of genera, species and varieties both cultivated and spontaneous that make this family certainly one of the richest in the vegetable kingdom, competing for the first place only withAsteraceae (the plants that are commonly called "daisies" to understand).Orchids are plants which have visible reproductive organs and belong to:
For what concern Kind there are about 775 while the Species there are about 19,500. The hybrids are innumerable (about 100,000)
They are widespread almost everywhere but for the most part they originate in the humid areas of the intertropical belt.
In Italy we have about 85 spontaneous species of orchids, distributed in wetlands both in the mountains and near the coasts, many of which are extremely rare and endangered and as such protected from indiscriminate harvesting. The species, the most diverse among them, reach the maximum of ecological differentiation with adaptations to the most diverse environments and with floral productions among the most beautiful in the vegetable kingdom.
The classification of orchids is very complex mainly due to the innumerable hybridizations between species and also between different genera that make the botanical classification uncertain. Suffice it to say that over 110,000 hybrids (called grexes or grex) have been produced in the last 150 years. Fortunately, they have fairly uniform general characteristics when considered on a floral organization level and therefore offer a very rare example of an infinity of shapes, colors, adaptations, which all converge in a single floral type.
For orchid hybrids, before 1962, their acceptance and classification was regulated by the international registry authority, from 1962 onwards it is regulated by the R.H.S. Royal Horticultural Society (founded in 1804 in England by Sir Joseph Banks and John Wedgwood). Over 3,000 new hybrids are added every year.
To simplify life for those who love orchids and want to know them a little more, we adopt a much simpler classification and which in everyday practice is much more useful, i.e. we adopt the BIOLOGICAL CLASSIFICATION according to which orchids are divided into:EPIPHITE: they are orchids that have only aerial roots and grow attached to the trees they use as a support.
The roots are hanging and have the characteristic of having a sort of cap in the terminal part and are covered with a spongy tissue called velamen which, with chlorophyll, photosynthesizes and absorbs water vapor from the atmosphere.
The stem it is erect and can be up to 10 m long (as in the case of Vanilla fragrans). It has also typical forms tuberized swellings that contain mucilages designed to retain water and reserve nutritional elements and in this case it is called pseudobulb.
The stem of the orchid can have a trend monopodial that is, with a single root (foot) that extends upwards and with a rhizome or sympodial that is, with more 1st order lateral roots (feet) which grow to equal the main root.
Epiphytic orchids receive moisture and nutrients from the air and humus that collects in the bark of trees.
They are typical orchids of tropical areas and therefore their ideal habitat is humidity and high temperatures. The best known and most cultivated genera of epiphytic orchids are: Cymbidium, Cattleya, Vanda, Odontoglossum.
Then there are also orchids EPIPHITE SEEDS, plants that live on the branches and trunks of other plants or LITHOPHITE, that is to say that they live on the rocks covered by a thin layer of plant fragments, mosses and lichens. Classic examples are the Phalaenopsis, Dendrobium, Vanda, etc. while for example the Cattleya, it can be epiphytic or semi epiphytic.
SCANDING: they are orchids rooted in the ground and by means of volatile stems they attach themselves to different substrates and have aerial type roots. A classic example is the Vanilla (photo below).
TERRESTRIAL: they are the orchids widespread in temperate climates that grow in the ground and the roots are firmly in the earth from which they draw the nutritional elements. They are typical examples Cymbidium, Cypripedium, Bletilla, Paphilopedilum.
In terrestrial orchids there are formations called tubercles formed by the welding of some roots, black when they fed the bud of the year and white that will supply the substances to that of the future year.
ORCHIDS THAT LIVE PARASITICALLY: they are orchids without chlorophyll that lead a heterotrophic life (feeding on organic material present in the environment) such as mushrooms, at the expense of humus or soil materials. Some have fungal-infected roots, others like Corallorhiza (photo below) are rootless and their role is assumed by the coral-like ramifications of the rhizome.