Most orchids are epiphytic, residing on tree limbs without parasitizing? resources (as Mistletoes do). Others live on the ground, in shaded places often. Almost all the species rely heavily upon mycorhizal associations with various fungi that decompose surounding matter, freeing up water-soluble nutrients. Most orchid seeds are extremely tiny, with no food reserves, and will not even germinate without such symbiosis? to supply nutrients in the wild. Techniques have now been devised for germinating seeds on a nutrient-containing gel, eliminating the necesity of the fungus, and greatly aiding the propagation of rare and endangered species.
It is in their reproductive methods that Orchids truly shine. The Paphiopedilums (Lady Slippers) have a deep pocket that traps visitors, with just one egress that leads to pollination. A Eurasian genus has flowers that look so much like female bumble bees that males flying nearby are irresistably drawn in. An underground orchid in Australia never sees the light of day, but manages to dupe ants into pollinating it. The Masdevalia stinks like a rotting Carcas, and the forest flies it attracts assist its reproduction. A species Darwin discussed briefly actually launches its pollen sacks with incendiary force when prompted. Some Phalaenopsis species in Malaysia use subtle weather cues to coordinate mass flowering.
There are a great number of tropical and subtropical orchids, and these are the most commonly known, as they are available at nurseries and through orchid clubs across the world. There are also quite a few orchids which grow in colder climates, although these are less often seen on the market.