Orchids

Orchidaceae, also called the Orchid family, is the largest family of the flowering plants (Angiospermae). Its name is derived from the genus Orchis. more...

The Royal Botanical Gardens of Kew list 880 genera and nearly 22,000 accepted species, but the exact number is unknown (perhaps as many as 25,000) because of taxonomic disputes. The number of orchid species equals about four times the number of mammal species, or more than twice the number of bird species. It also encompasses about 6–11% of all seed plants. About 800 new orchid species are added each year. The largest genera are Bulbophyllum (2,000 species), Epidendrum (1,500 species), Dendrobium (1,400 species) and Pleurothallis (1,000 species). The family also includes the Vanilla (the genus of the vanilla plant), Orchis (type genus) and many commonly cultivated plants like some Phalaenopsis or Cattleya.

Moreover, since the introduction of tropical species in the 19th century, horticulturists have more than 100,000 hybrids and cultivars.

Distribution

Orchidaceae are cosmopolitan, occurring in almost every habitat apart from deserts and glaciers. The great majority are to be found in the tropics, mostly Asia, South America and Central America. They are found above the Arctic Circle, in southern Patagonia and even on Macquarie Island, close to Antarctica.

The following list gives a rough overview of their distribution:

• tropical America: 300 to 350 genera
• tropical Asia: 250 to 300 genera
• tropical Africa: 125 to 150 genera
• Oceania: 50 to 70 genera
• Europe and temperate Asia: 40 to 60 genera
• North America: 20 to 30 genera

Taxonomy

This family is totally recognised, and the APG II system of 2003 places it in the order Asparagales.

The taxonomy of this family is in constant flux, as new studies continue to identify more classificatory elements.

Five subfamilies are now recognised. The cladogram has been made according to the APG system:

Ecology