(
Yellow and Red Cattleya Orchids; Photo courtesy of Melanie Votaw)
(
Yellow and Red Cattleya Orchids; Photo courtesy of Melanie Votaw)
Orchids
Background
Orchids are believed to become one of the first flowering plants when dinosaurs ruled the land and when plants were becoming widely and increasingly diverse. As times changed and both plant and animal species died out or were replaced, Orchids thrived and expanded. It is estimated that in the world today there are approximately 35,000 different species of Orchids.
Reproductively Orchids are very versatile in sense that they have widely adapted themselves to several different pollinators. Orchids can attract pollinators several ways by either smell, mimicry, or maybe even a "stealth" approach.
When it comes to
mimicry, a very good example is the Ophrys insectifera,
the "bee orchid" tries to lure in, obviously bees by mimicking different
reproductive organs of the opposite sex. For instance, male bees are highly
attracted to these specific Orchids simply because the flower closely resembles
a receptive female. When the male bee tries to reproduce with the flower he
picks up pollen on his body and becomes a pollen carrier. Some Orchids even try
to lure in pollinators. A fine example of this is Oncidium
Papillio. These Orchids have very long stems
that one the ends have flowers that when there is a breeze look like butterflies
fluttering.
Many Orchids contain a "landing platform" for pollinators. This is so that when the pollinator tries to get to the nectar it has to touch the pollen of the Orchid, which then breaks off and when the pollinator visits another flower the pollen from the Orchid is transported. Some Orchids even have a "hinge and tilt" mechanism to its lip. This device ensures that when the pollinator visits the plant it is slapped against the pollinia as it enters into the flower for nectar.
(Photo courtesy of Master Gardener Landscaping of Ft. Lauderdale)
As pertaining to th
e
stealth mechanism a great example of this is the slipper orchid, uses its scent
and its pouch to lure in pollinators, and when the insect lands on the
edge of its pouch, which is extremely slippery, hence slippery orchid, the
insect will slip into the pouch with the only way on getting out is to exit a
"side door" that is a very tight squeeze and when the insect passes through the
exit the pollen is then attached to the insect and dispersed when it visits
another flower.
(Green Spotted Slipper Orchid; Photo courtesy of Melanie Votaw.)
Orchids like other plants can't simply rely on insects to pollinate them. Orchids also rely on birds in particular hummingbirds, mammals, and what seems to be the least important, the wind. Orchids produce millions of seeds, as many as 4 million at one time. Logically it would seem that Orchids wouldn't have any problem at all in reproduction. However, Orchid seeds lack the natural reservoir of food that other seeds have, it does not also possess the ability to make its own food source that it needs. In light of this Orchid seeds and fungi embark on a somewhat weird relationship. The fungus must infect the seed early in the life cycle if the seed is to develop into a mature plant. The mycorrhizal filaments of the fungus becomes it's "lifeline".
How do Orchids Differ From Other Plants?
Orchids and other flowering plants differ greatly in many aspects; but the one defining aspect would be the reproductive organs. On other flowering plants the anther and stigma are separate in all aspects. On an Orchid they are one unit, called a column. The pollen of an orchid, unlike the dust pollen of other plants, is sticky balls called pollinia. They rest at the top of the column, where any insect who goes for nectar will rub these pollinia collect pollen on its body. Another highly significant differences between Orchids and other flowers is that Orchids are considered zygomorphic. Zygomorphic means that Orchids can be split into halves on only one plane and be identical to the other half.
Where and How do Orchids Grow?
Orchids are mostly seen
growing 
in
diversity in tropical areas such as Southeast Asia, South America, and other
warm climates. The only place that Orchids do not grow is Polar regions.
Australia is very rich in Orchid species containing approximately 700 unique
species and some of which are not found anywhere else in the world. There are
basically 2 different types of Orchids; Epiphyte and Terrestrial. Epiphyte
Orchids grow atop of stationary items in nature. For instance trees. Orchids are
commonly seen growing on trees. One common misconception is that Orchids are
parasitic. That is wrong, Orchids simply use trees and other things to perch
upon. Orchids generally require circulating air and humid environments. Orchids
are also very hardy flowers. They can survive rough times when water is
rare, they store water in pseudo bulbs for when times are such. They are able to
pull nutrients from debris that falls and from rain water.
(Orchids growing on a dead tree; Photo courtesy of Orchid Tips.)
How are Orchids Used?
In the older days, Orchids were identified with sexual healing and began to acquire an exotic reputation. Orchids have also been known to be used for medicinal purposes. The dried roots of Orchids were used in Greece and Asia as antidepressants, stimulants, and aphrodisiacs. A drink called "salep" is still used today as an aphrodisiac in Turkey. Orchids are used for food and medicine in other cultures as well, such as Vanilla used by the ancient Aztecs; Gastrodia and Dendrobium used in China to treat minor ailments, Oncidium for divination, and the African Ansellia used as an aphrodisiac.
How Are Orchids Being Threatened?
Many people are highly
fascinated with Orchids and want to grow them in their homes. Unfortunately one
of the common ways
of doing
so it removing the Orchid from its natural habitat. This is one of the causes of
many of the Orchids becoming extremely rare. Another threat to Orchids is the
over exploitation for mainly medicinal purposes. Exotics in the habitat is also
beginning to increasingly danger the Orchids. The biggest threat by far is the
destruction of the natural habitats urban or agricultural development and
for forestry. Currently there are about 100 southern African orchids
listed as being threatened with extinction in the wild, and five are already
extinct.
(Satyrium hallackii, left, is one of many endangered species; Photo courtesy of Hubert Kurzweil.)