The largest number of orchids, and often the most popular, come from Asia. This is the home of the Paphiopedilum, the striking Lady slipper orchid. South America is also especially rich in wild orchids, but really they can be found in any conditions almost anywhere except the polar regions. Groupings Orchids can be grouped according to their growth habits and roots. These are not taxonomic classifications, but helpful guidelines to understanding their evolutionary adaptability and care requirements.
Orchids have two main ways of growing.
In monopodial growth, there is one, usually upright growth axis from which the leaves appear. In sympodial growth, the growth axis is a prostrate rhizome which sends off shoots. Many sympodials develop pseudobulbs, which are thickened shoots from which the leaves grow. Pseudobulbs act as storage organs for water and nutrients. Terrestrial roots resemble those of other plants.