All About Tropical Orchids
The most common tropical orchids are:
- Dendrobiums – about 1200 species
- Vandas – about 50 species
- Cattleyas – more than 40 species
- Oncidiums – more than 300 species
Some species grow in soil, but the majority grow on trees or rocks, which makes them unique. Most of them come from the humid tropical rain forests of Asia, Australia and South America. The rain forests of the world provide a great environment for tropical orchids as they most typically live in filtered sunlight, which is the best medium for growing orchids.
If you decide you want to grow them, provide them with light but make sure it’s filtered so they don’t get exposed to direct sunlight. Vandas require the most amount of light because of their small shaped leaves. Dendrobiums, Cattleyas and Oncidiums prefer shadier spots or morning sun locations.
The main part of the orchid actually has more varieties than the floral ones. When you consider the habitats where they are grown it’s not surprising. Orchids can grow on the moisture rich floor of the rain forest, high up in the trees of the tropical rain forest where heavy rainfall is following by scorching sun, on rocks and in grassy areas. Orchids can adapt to any adverse environment, particularly in the case of water conservation.
If tropical orchids suffer from periodic water deficit, it’s not immediately obvious, as rainfall is not always continuous and heavy rainfall is mainly seasonal. When they grow on trees, twigs or rocks, the rainfall runoff is rapid and the sunshine which follows, dries them out quickly. Many orchids have adapted to these situations by growing one or more organs which helps them survive during periods of drought.
The leaf is another part which has been modified over time. A number of orchids have no green leaves and have been reduced to scales. Photosynthesis takes place in the flattened green roots. Some orchids such as the ghost orchid, are leafless and lack chlorophyll, cannot photosynthesize and obtain all of their nutrients from a fungus it is associated with. Most leaves from orchids are ornamental and one particular species called Macodes Sanderiana, show a sparkling silver gold veining on a light green background.
Life in the tropics can be very harsh for orchids, and can be very hostile at certain times of the year. Even in the tropical rain forest, orchids have to survive days or weeks without water, so have to drop their leaves and stems, which soak up the moisture on the ground, and soak it up through their roots. The roots have an actively growing tip with the older parts being covered in an envelope of dead empty cells. The tip protects the inner tissues which aid in the uptake of moisture from the atmosphere. This provides a blotting paper effect for the orchid.
Tropical orchids thrive best in day temperatures ranging from 75-90 degrees F and night time temperatures no lower than 55 degrees F.
Because orchids are well adapted to living outdoors, high up in the trees, it’s important when growing them indoors to place them in a well ventilated area. This ensures that the natural ventilation keeps the roots dry and free from moisture loving pests.
The chances of an orchid being pollinated are very scarce as they have devised a highly specialized system. Orchid flowers usually remain receptive for quite a long period and sometimes deliver pollen in a single mass. Once pollination occurs, thousands of ovules (small eggs) can be fertilized.
The orchid is known as a monocot with leaves which have parallel lines. Orchids produce one single flower, but most produce a large number of flowers. The orchid flower is a monocot and has two whorls of sterile elements. The outer whorl has three sepals while the outer whorl has three petals, with the sepals being similar to the petals and thus called tepals. Whereas primitive orchids used to have two or three stamens, but present day orchids have only one single stamen.
In several species of orchids the flowers all grow on the same side of the rhachis (spine). In one of the most spectacular groups, the stem is so contracted that the flowers all seem to come from the top of the flower stalk.
