I did 1 whole day research and then made this just so that i can make its slide and its really good and should read it if u like i took some paras from google

2. Orchid
orchid, (family Orchidaceae), any of nearly 1,000 genera and more than 25,000 species of attractively flowered plants distributed
throughout the world, especially in wet tropics. Orchidaceae is a member of Asparaguses, an order of monocotyledonous flowering
plants that also includes the asparagus and iris families. The word orchid is derived from the Greek word (orchis) for testicle because of
the shape of the root tubers in some species of the genus Orchis. These nonwoody perennial plants are generally terrestrial or epiphytic
herbs (i.e., growing on other plants rather than rooted in soil). Those attached to other plants often are vinelike and have a spongy root
covering called the velamen that absorbs water from the surrounding air. Most species manufacture their own food, but some live on
dead organic material (saprophytic) or are helped to obtain nourishment by a fungus living in their roots.

3. Structural diversity
As a group, the orchids are different from other plants but only in the morphological (structural) characteristics associated
with the flower and its organization. Even the special characteristics of orchid flowers, such as the masses of pollen called
pollinia, the joining of the stamens and pistil to form a column, and the tiny seeds without endosperm are found individually
in other groups of flowering plants. It is through the combination of several characteristics that a family of flowering plants,
the Orchidaceae, emerges.

4. Ecology
Orchids have a wide ecological distribution when the entire family is considered. Although the family is primarily tropical, a number
of species are found in the northern and southern temperate zones. At least four species have been reported from north of the Arctic
Circle. A number of species of the North Temperate Zone are found in bogs, prairies, grasslands, and hardwood forests.
Several species of Spirants, Habanera, and other orchids are found in roadside ditches, often in wet, boggy situations. In some areas of
the United States, Panthera ciliary might almost be considered a weed. The introduced Asian species Zebuine strateumatica in
southern Florida is now widespread and may be considered a weed.
Orchids vary from those species that are very widespread, such as the species found throughout most of the tropical regions of the
Western Hemisphere (e.g., Ionopsis utricularioides), to some species that seem to be restricted to a single mountain. In the West Indies,
each of the major islands has a fair number of such restricted species.

5. Economic importance
The orchid family is probably one of the most important of plant families from a horticultural point of view. Other than the horticultural
uses to which orchids are put, the family is notably lacking in species from which products are derived. The only commercially important
product derived from orchids is vanilla. Most vanilla is produced from one species, Vanilla planifolia, although two additional species are
also cultivated commercially (V. pompona and V. tahitensis). The principal vanilla-growing areas are Madagascar, Mexico, French
Polynesia, Réunion, Dominica, Indonesia, the West Indies, Seychelles, and Puerto Rico. Vanilla is grown from sea level to about 600
meters in elevation. The plant is a climbing vine that is indigenous to the tropical regions of the Western Hemisphere.
Various other orchids are used for a variety of folk medicines and cures. In the West Indies, the bulbs of Bletia purpurea are boiled, and
the liquid is thought to cure poisoning from fish. In Malaysia, women take a drink made from the boiled leaves of Nervilia aragoana to
prevent sickness after childbirth. In Melaka (formerly Malacca), a state in western Malaysia, boils are treated with a poultice made from
the entire plant of Oberonia anceps. In Chile, Spiranthes diuretica is known to be a strong diuretic. In certain parts of Ecuador, the
mucilage from Catasetum is thought to be good for broken bones. In various parts of the world, certain orchids are also used for food or
food supplements. In Malaysia, the leaves of one species of Anoectochilus are sold as a vegetable, and the leaves of Dendrobium
salaccense are cooked as a seasoning with rice. In certain parts of the Asian tropics, the tubers of some species of Gastrodia are eaten like
potatoes. Throughout the world several species of orchids are used as a glue substitute. In most cases, the glue is derived from the
pseudobulbs. Salep is derived from the tubers of several species of Orchis. The tubers are boiled, then dried and powdered. The resulting
preparation is often used as a flour substitute.

6. Characteristic morphological features
The primary characteristics that distinguish the orchids as a group are found in the flower. At the bottom of an unspecialized non-orchid flower is the stem
that supports it, called the pedicel. Directly above, and at the base of the flower itself, is a whorl of green, leaflike organs called sepals. Above and inside the
sepals is a second whorl of colored petals. Together the sepals and petals are called the perianth, which constitute the nonreproductive parts of the flower.
The perianth protects the flower or attracts pollinators or both. Inside (also arranged in whorls) are the sexual portions of the flower. First are the pollen-
producing stamens in up to several whorls; each stamen consists of an anther on a long slender filament. In the center of the flower is the female pistil,
which consists of an enlarged inferior ovary topped by a stalk like style with a stigma at its apex. The sepals and petals are usually similar, often highly
colored, and in sets of three. One petal is developed as a landing platform for the pollinator and is called the lip (or labellum).
The sexual portions of the orchid flower are quite different from other generalized flowers, and they tend to characterize the family. The filaments, anthers,
style, and stigma are reduced in number and are usually fused into a single structure called the column. The majority of the orchids retain only a single
anther at the apex of the column.
In the orchid the ovary is composed of three carpels fused so that the only outward evidence of their existence is the three ridges on the outside of the seed
pods. The mature seed pod opens down the middle between the lines of juncture. The ovules are arranged along the ridges inside the ovary and do not
develop until some time after the flower has been pollinated, thereby contributing to the long delay between pollination and the opening of a ripened pod.

7. Natural history
The life cycle of an orchid is not essentially different from that of any other flowering plant. When the pollinator leaves one or more pollinia on the
stigma, the pollen tubes germinate and grow down the centre of the column to reach the developing ovules in the ovary. This often causes the sides
of the stigma to swell around the stigma and the enclosed pollinia. When the pollen tubes reach the ovules after about six weeks or longer, one or
more ovules are fertilized, and the resulting zygotes develop into embryos. Most angiosperms undergo double fertilization, one of which forms the
zygote and the other an endosperm that nourishes the developing plant upon germination until the plant is able to manufacture its own food. The
orchid seed, however, has no endosperm. The seed consists of a simple, dry, outer coat enclosing a small mass of undifferentiated cells that form a
pro-embryo. This extremely small and light unit can easily be carried in air currents and may travel long distances before coming to rest. The large
number of seeds in a single orchid capsule undoubtedly is correlated with the unlikelihood of a seed’s falling in a favorable spot
during wind dispersal.
The presence of the labellum as a landing platform for insect pollinators and the reduction of the stamens and pistil of a flower to a single
structure, the column, is certainly the apex of floral adaptation to insects as pollinating agents. Once achieved, this combination provides a
foundation for all kinds of specializations for attracting of specific pollinators.
The function of pollen deposition is centralized precisely in the median plane opposite the labellum. Being directed back toward the centre of
the flower, the anther deposits pollen on the most advantageous side of the visitor, considering efficiency in reception and deposition. This
precision is also expressed by a tendency of orchids to deposit the pollen as two to eight masses, the pollinia.

8. Orchids as a group use nectar as the major attractant, whereas pollen, sought by pollinators among more primitive plant families as a
protein-rich food, has been withdrawn. This is tied to the exactness of the mechanics of pollination, but it also means that orchids can no
longer provide the only source of sustenance for the pollinator, and other flowers must be present in the biosphere to maintain visitors.
Nectar is provided in tubular nectarines (Brassavola, Angraecum, Comparettia, and other genera), in grooves on the labellum (e.g., Listeria
and Epilates), and at the base of the column and lip (e.g., Dendrobium and Scaphyglottis). A large number of orchids are nectar less and
have developed other means of attracting pollinators, largely consisting of deceptive attractants in one form or another.
Many orchids attract pollinators with pseudopollen, a powdery mass resembling pollen that is found on the labellum of a number of
species of Maxillaria and Polystachya. Sometimes the grains are detached outgrowths called papillae, and sometimes they are disintegrated
multicellular hairs that are filled with starch.
Flowers pollinated by bees open during the day and tend to have similar characteristics: agreeable odors, bright colors (except red, which
bees see as black or gray), a landing platform, nectar guides in the form of colored lines running into the depths of the flower, and
concealed nectaries. The basal portions of the orchid lip are usually formed into a tunnel with the column constituting its upper side. The
bee enters the tunnel to get at the nectary, and as the bee backs out some of the stigmatic fluid may be rubbed on its back. As the bee
backs farther, the pollinia become attached to the sticky material and are carried with the bee to the next flower. In more advanced orchids
the pollinia may be attached to a sticky pad, the viscidium, which becomes detached from part of the stigma and sticks to the pollinator.
Some species of orchids are pollinated by bees that are attracted by means of deception. The flowers of the large genus Oncidium, for
example, are pollinated by male Centris bees in what appears to be a case of pseudo antagonism. The flower seems to simulate an enemy
insect, which the male bee tries to drive away from his territory. As the bee strikes at the flower, the pollinia are attached to the head of
the bee.

9. The most exciting and unusual examples of deceit, traps, and manipulation of pollinators are to be found in those orchids that are pollinated by male euglossine
bees (species of the bee tribe Euglossini). The syndrome of flowers that are pollinated by male euglossini is based on the attraction of the male bees to the
odour of the flower. In no case does the male euglossini bee receive food from the orchid that it visits. The euglossini male bees visit other nectar-producing
flowers for their food, but, when the male bees visit the non-nectar-producing orchid flowers, they rub the surface of the lip with their front feet and collect in
special tarsal brushes the odour that is produced there. The bees then launch themselves into the air and transfer the odor to their hind tibiae (leg segments),
which have become noticeably swollen. It is in the process of transferring the odor to the hind tibiae that the bee is manipulated by the orchid.
Another variation of pollinator manipulation by orchids is found in the genus Coryanthes. The flowers are very large and might even be considered grotesque.
The sepals and petals fold back out of the way when the flower opens—like sails on a boat—revealing a strangely formed lip divided into three parts: a globular-
or hood-shaped portion called the hypochile above; an elongate, sometimes fluted part, the mesochile; and a bucket-shaped epichile. The epichile is partially
filled with water during the last few hours before the flower opens and for a short time afterward by two faucetlike organs located at the base of the column,
which drip water. Male euglossine bees are attracted by the strong odour produced by the hypochile, where they scratch. In trying to launch into the air to
transfer the odour to their hind legs, the bees occasionally fall into the water-filled bucket. The sides of the bucket are vertical and are very waxy, so that the
bee is not able to climb out of the bucket. The only way for the bee to get out is through a small tunnel formed by the apex of the column and the apex of the
epichile of the lip. As the bee forces its way out of the tunnel, the pollinarium is deposited on its thorax. The pollinia may then be deposited in the stigma of
another flower on a next visit, provided the original pollinia of that flower have already been removed and the stigmatic cleft has opened sufficiently to become
receptive.
Because moths normally fly at night, they are attracted to flowers that produce strong odours and are white or light-colored. Moths hover in front of the flower
while extracting the nectar. The typical moth-pollinated flower has a long, slender nectar tube containing abundant nectar. The fragrance produced is typically
sweet or musky, and the flowers usually are horizontal or hanging. Butterflies, on the other hand, are day fliers and are attracted to highly colored flowers that
may or may not be fragrant. Butterflies tend to be somewhat erratic fliers and, lacking the ability to hover, usually land on the flower. The flowers are, therefore,
usually erect and provide platforms for landing. Often the platform simply consists of a head of erect, densely packed flowers. Butterflies detect colors well, and
butterfly-pollinated flowers are usually brightly colored with red, orange, or yellow predominating. Nectar is commonly abundant and is hidden in deep nectar
tubes. In most of the moth- and butterfly-pollinated orchids, the nectar tube is arranged to guide the tongue or beak in such a manner that the pollinia are
correctly attached to the pollinating organism.

10. In an oft-cited case, Charles Darwin, the English naturalist, predicted that a moth with a 25-centimetre-long proboscis would eventually be
found on the island of Madagascar as the pollinator of the orchid Angraecum sesquipedale, since a moth would need a long tongue to reach
the nectar hidden in the very long nectary at the base of the lip. Such a moth has been found and has been observed pollinating the flowers
of this amazing orchid.
Flowers adapted to pollination by birds are usually brightly colored, with reds, blues, and yellows predominating. They are usually tubular in
form, often with a long nectary, and nectar is almost always present. Birds have little or no sense of smell, and bird-pollinated flowers tend
to lack odour; however, the bright colors serve to attract the birds. Bird-pollinated orchids tend to follow the pattern of other bird flowers,
but in some cases they diverge considerably. Many orchids of the Western Hemisphere appear to have adapted to bird pollination as an
extension of butterfly pollination, and, as in the case of Epidendrum secundum, birds and butterflies act as copollinators. In such cases,
orchid flowers already adapted to butterflies are not greatly changed morphologically. On the other hand, orchids that have adapted directly
to hummingbirds from bee-pollinated ancestors have changed fundamentally. The genera Cochlioda, Sophronitis, Elleanthus, Isochilus,
Comparettia, Hexisea, and Meiracyllium are all bird-pollinated and are remarkably similar in certain aspects. All have bright colors, tubular
form, and a callus or hump in the interior of the tube, on the lip, which acts to force the beak of the bird against the column.
Some flies are important pollinators of flowers, and certain families of flies (e.g., the Syrphidae and Bombyliidae) are restricted to flowers
for their food. Unspecialized flowers may attract flies to nectar, which is present in open, shallow nectaries and may emit sweet odours. The
flies eat the nectar and do not store it as do bees. More specialized fly flowers may attract flies through deception, imitating decaying
substances, dung, or carrion. For example, the flowers of B. nocturnum, the only orchid known to flower exclusively at night, are thought to
attract fly pollinators by mimicking fungi in both shape and scent. Nocturnal flies are then attracted and act as effective pollinators.
Fly-pollinated flowers have often developed traps for catching and holding unadopted visitors. They commonly have large landing surfaces
and “tails” produced from the flower parts, which function as guides. Their colors are usually checkered or blotched and tend toward dull
green, brown, purple, or red. The odours produced are commonly putrescent. Orchids pollinated by flies are common throughout the world.
In most fly-pollinated orchids, special adaptations have developed—superimposed on the basic pattern of the bee-pollinated orchid
flower—to guide the somewhat poorly oriented flies. Certain of the five petals may be long and taillike (as in Bulbophyllum and
Masdevallia) or joined to form a flat radial flower (as in Stelis). The flowers themselves may be arranged to form a larger radial, compound
“flower” (as in Cirrhopetalum). The petals or lip may be fringed with motile clublike hairs that vibrate in the wind and attract the flies
(Bulbophyllum). Often the sepals are joined or the lip is saccate to form a trap (Pterostylis) into which the flies fall and from which they must
crawl by way of a tunnel that passes the stigma and anther. A common contrivance by which orchids exploit flies is a hinged, balanced lip
that tips with the weight of the fly and launches the pollinator into the flower.

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