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ORCHID DISTRIBUTION
There is hardly one region of the world without orchids, given their success in adapting to and colonizing almost every conceivable niche on land. Some species such as Cypripedium passerinum, Cypripedium guttatum, and Coeloglossum viride flower within the Arctic Circle (Luer 1975), while Corybas macranthus grows in sphagnum bogs on Macquarie island (Jones, 1988), a scant 1,000 miles from Antarctica. The vast majority of orchid species, however, occur in the tropics, especially the Neotropics.
Tropical rain forests at lower elevations are relatively poor in terms of numbers os orchid species.

Dressier (1981) estimated that as many as 3,000 species occur in Colombia, 2,500 in Brazil, and 1,500 in Venezuela. Tropical Africa has about 3,100 species and tropical Asia some 6,800. The Malay Archipelago, including Borneo and New Guinea, is also particularly rich in species. The estimate of orchid species in Australasia has risen from Dressler's figure of 600 to about 900 (Clements, 1989; Jones, 1991) in the last ten years, As exploration and research continue, hundreds more are likely to be found worldwide.

The greaatest diversity of orchid species is found in mountane cloud forests, such us these in the Columbian Andes, between about 1000 and 2000 meters abpve the sea level.
Even in the tropics, orchids are distributed differently according to elevation gradients. Diversity is highest in montane cloud forests between roughly 1,000 and 2,000 meters above sea level; as many as 47 different species were found on one tree by the great orchid explorer and taxonomist G. C. K. Dunsterville in Venezuela (Dressler, 1981). Species richness declines both in warm to hot lowland rain forests and above the timber line. Although orchids are most common in woodlands, they seem to pop up in the most unexpected places: swamps and peat bogs, sandy dunes around salt lakes, semi-desert scrub in blazing sun, savannas, paramo, alpine meadows, elfin forest, your own back yard. it all comes down to this: it is easier to list the habitats in which orchids do not occur than those where they do.

Many orchid genera are pantropical; Vanilla is one good example, distributed from Latin America, to equatorial Africa, to southeast Asia. At the other extreme are hundreds if not thousands of species endemic (restricted) to specific countries, mountain ranges, valleys, or even more localized sites. Consistent with its long, isolated geologic history, Australia's flora has a high degree of endemism; roughly 88 per cent of the terrestrial orchids do not occur elsewhere (Jones, 1988). Because of the high levels of endemism and their sporadic and wide dispersal, many orchid populations suffer with both loss of habitat to agriculture and logging, and also overcollecting. The removal of one tree or a few plants can seriously cripple the reproductive potential and gene flow of the entire population. For species already endangered, especially those that are self-incompatible, reduction in gene flow can rapidly reduce fitness and adaptability.

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