Changes

==Leaves==

==Leaves==

[[image:Dendrobium crumenatum.jpg|thumb|250px|right|This small orchid demonstrates a typical [[zygomorphic]] flower with three petal-like [[sepal]]s (top, lower right, lower left), two normal [[petal]]s on either side of the dorsal (upper) sepal, and  the [[labellum]], a modified lower petal in three parts surrounding and below the shiny column.]]

[[image:Dendrobium crumenatum.jpg|thumb|250px|right|This small orchid demonstrates a typical [[zygomorphic]] flower with three petal-like [[sepal]]s (top, lower right, lower left), two normal [[petal]]s on either side of the dorsal (upper) sepal, and  the [[labellum]], a modified lower petal in three parts surrounding and below the shiny column.]]

Orchids have simple [[Leaf|leaves]] with parallel [[vein]]s. Their shape is highly variable between species; ovate, lanceolate, or orbiculate. Their size and shape can be an aid in identifying the orchid, since it reflects the taxonomic position. The leaves can be enormous or minute, or they can even be lacking (as in the [[Ghost Orchid]] (''Dendrophylax lindenii''), a mycoheterotrophic species, and ''[[Aphyllorchis]]'' and ''[[Taeniophyllum]]'', which depend on their roots, which contain chlorophyll for [[photosynthesis]]).

Orchids have simple [[Leaf|leaves]] with parallel [[vein]]s. Their shape is highly variable between species; ovate, lanceolate, or orbiculate. Their size and shape can be an aid in identifying the orchid, since it reflects the taxonomic position. The leaves can be enormous or minute, or they can even be lacking (as in the [[Ghost Orchid]] (''Dendrophylax lindenii''), a mycoheterotrophic species, and ''[[Aphyllorchis]]'' and ''[[Taeniophyllum]]'', which depend on their roots, which contain chlorophyll for [[photosynthesis]]).

The structure of the leaves corresponds to the specific habitat of the orchid. Species that typically bask in sunlight, or grow on sites which can be occasionally very dry, have thick, leathery leaves. The [[lamina]]s are covered by a waxy [[cuticle]]. These retain their necessary water supply. Shade species, on the other hand, have tall, thin leaves. They cannot tolerate a drop in atmospheric humidity or exposure to direct sunlight. Between these two extremes, there is a whole range of intermediate forms.

The structure of the leaves corresponds to the specific habitat of the orchid. Species that typically bask in sunlight, or grow on sites which can be occasionally very dry, have thick, leathery leaves. The [[lamina]]s are covered by a waxy [[cuticle]]. These retain their necessary water supply. Shade species, on the other hand, have tall, thin leaves. They cannot tolerate a drop in atmospheric humidity or exposure to direct sunlight. Between these two extremes, there is a whole range of intermediate forms.

The leaves of most orchids live on, attached to their [[pseudobulbs]], for several years. Some species, especially those with plicate leaves, shed their aged leaves annually, through an articulation between the lamina and the [[Petiole (botany)|petiole]] sheath, and develop new leaves together with  

The leaves of most orchids live on, attached to their [[pseudobulbs]], for several years. Some species, especially those with plicate leaves, shed their aged leaves annually, through an articulation between the lamina and the [[Petiole (botany)|petiole]] sheath, and develop new leaves together with new pseudobulbs (as in the genus ''[[Catasetum]]'').

new pseudobulbs (as in the genus ''[[Catasetum]]'').

The leaves of some species can be most beautiful. The leaves of the ''Macodes sanderiana'', a semiterrestrial or lithophyte, show a sparkling silver and gold veining on a light green background. The cordate leaves of ''Psychopsiella limminghei'' are light brownish green with maroon-puce markings, created by flower pigments. The attractive mottle of the leaves of [[Lady's Slipper]]s from temperate zones (''[[Paphiopedilum]]'') is caused by uneven distribution of chlorophyll. Also ''Phalaenopsis schilleriana'' is a lovely pastel pink orchid with leaves spotted dark green and light green. The Jewel Orchid (''Ludisia discolor'') is grown more for its colorful leaves than its fairly inconspicuous white flowers.

The leaves of some species can be most beautiful. The leaves of the ''Macodes sanderiana'', a semiterrestrial or lithophyte, show a sparkling silver and gold veining on a light green background. The cordate leaves of ''Psychopsiella limminghei'' are light brownish green with maroon-puce markings, created by flower pigments. The attractive mottle of the leaves of [[Lady's Slipper]]s from temperate zones (''[[Paphiopedilum]]'') is caused by uneven distribution of chlorophyll. Also ''Phalaenopsis schilleriana'' is a lovely pastel pink orchid with leaves spotted dark green and light green. The Jewel Orchid (''Ludisia discolor'') is grown more for its colorful leaves than its fairly inconspicuous white flowers.

==Plant thallus and roots==

==Plant thallus and roots==

[[image:Pseudobulbs_new.jpg|thumb|right|[[Pseudobulb]]s of an [[epiphytic]] orchid]]  

[[image:Pseudobulbs_new.jpg|thumb|right|[[Pseudobulb]]s of an [[epiphytic]] orchid]]  

All orchids are [[perennial]] herbs, lacking any permanent [[wood]]y structure.  

All orchids are [[perennial]] herbs, lacking any permanent [[wood]]y structure.  

*Several species are [[lithophyte]]s, especially in rocky mountain ranges in [[Australia]] and [[Tasmania]], central [[Brazil]] and [[Africa]].  

*Several species are [[lithophyte]]s, especially in rocky mountain ranges in [[Australia]] and [[Tasmania]], central [[Brazil]] and [[Africa]].  

The base of the stem of sympodial epiphytes, or in some species essentially the entire stem, may be thickened to form what is called a ''',[[pseudobulb]]'''. These contain nutrients and water for drier periods. Pseudobulbs have a smooth surface with lengthwise grooves. They typically stay alive for five or six years. They look on the inside more like a corm than the embryonal stage of leaf sheaths. They have different sizes and shapes. They can be conical or oblong. In the Black Orchids (''[[Bulbophyllum]]''), the pseudobulbs are no longer than 2 mm. The largest orchid in the world, the [[Giant Orchid]] (''Grammatophyllum speciosum''), has pseudobulbs with lengths of 2–3 m. When the orchid has aged and the pseudobulb has shed its leaves, the pseudobulb becomes dormant and is called

The base of the stem of sympodial epiphytes, or in some species essentially the entire stem, may be thickened to form what is called a ''',[[pseudobulb]]'''. These contain nutrients and water for drier periods. Pseudobulbs have a smooth surface with lengthwise grooves. They typically stay alive for five or six years. They look on the inside more like a corm than the embryonal stage of leaf sheaths. They have different sizes and shapes. They can be conical or oblong. In the Black Orchids (''[[Bulbophyllum]]''), the pseudobulbs are no longer than 2 mm. The largest orchid in the world, the [[Giant Orchid]] (''Grammatophyllum speciosum''), has pseudobulbs with lengths of 2–3 m. When the orchid has aged and the pseudobulb has shed its leaves, the pseudobulb becomes dormant and is called a '''backbulb'''. The next year's pseudobulb then takes over, exploiting the last reserves of the backbulb. Eventually, the backbulb also dies off, having given life to newer growths. At the end of the pseudobulb typically appear one or two leaves, though there may be up to a dozen or more. Some ''[[Dendrobium]]'' have long, canelike pseudobulbs with short, rounded leaves over the whole length. Some orchids have hidden or extremely small pseudobulbs hidden completely inside leaves.

a '''backbulb'''. The next year's pseudobulb then takes over, exploiting the last reserves of the backbulb. Eventually, the backbulb also dies off, having given life to newer growths. At the end of the pseudobulb typically appear one or two leaves, though there may be up to a dozen or more. Some ''[[Dendrobium]]'' have long, canelike pseudobulbs with short, rounded leaves over the whole length. Some orchids have hidden or extremely small pseudobulbs hidden completely inside leaves.

Some sympodial terrestrials, such as ''Orchis'' and ''[[Ophrys]]'', have two subterranean tubers (more like [[tuberous root]]s) between the [[root]]s. One is used as a food reserve for wintery periods, and provides for the development of the other pseudobulb, from which visible growth develops.  

Some sympodial terrestrials, such as ''Orchis'' and ''[[Ophrys]]'', have two subterranean tubers (more like [[tuberous root]]s) between the [[root]]s. One is used as a food reserve for wintery periods, and provides for the development of the other pseudobulb, from which visible growth develops.  

Sepals form the exterior of the bud. They are green in this stage, but sometimes, if the orchid blossom is, for example, purple, the buds can show a purple tint. When the flower opens, the sepals become intensely colored. Sepals may mimic petals such as in some phalaenopsis or be completely distinct. In many orchids, the sepals are mutually different and generally resemble the petals. It is not always easy to distinguish sepals and petals. The normal form can be found in ''[[Cattleya]]'', with three sepals forming a triangle. But in Venus Slippers (''Paphiopedilum'') the lower two sepals are concrescent (fused together into a [[synsepal]]), while the lip has taken the form of a slipper. In ''[[Masdevallia]]'' all the sepals are fused into a [[calyx (flower)|calyx]]. In an example like this the sepals are very prominent, especially in lycaste orchids, the actual petals become diminished and inconspicuous.

Sepals form the exterior of the bud. They are green in this stage, but sometimes, if the orchid blossom is, for example, purple, the buds can show a purple tint. When the flower opens, the sepals become intensely colored. Sepals may mimic petals such as in some phalaenopsis or be completely distinct. In many orchids, the sepals are mutually different and generally resemble the petals. It is not always easy to distinguish sepals and petals. The normal form can be found in ''[[Cattleya]]'', with three sepals forming a triangle. But in Venus Slippers (''Paphiopedilum'') the lower two sepals are concrescent (fused together into a [[synsepal]]), while the lip has taken the form of a slipper. In ''[[Masdevallia]]'' all the sepals are fused into a [[calyx (flower)|calyx]]. In an example like this the sepals are very prominent, especially in lycaste orchids, the actual petals become diminished and inconspicuous.

The [[reproductive organ]]s in the center ([[stamen]]s and [[carpel|pistil]]) have adapted to become a cylindrical structure called the [[column (botany)|column]] or gynandrium. On top of the column lies the [[Carpel|stigma]], the vestiges of stamens and the [[Pollinium|pollinia]], a mass of waxy [[pollen]] on filaments. These filaments can be a '''[[caudicle]]''' (as in ''[[Habenaria]]'') or a '''[[stipe (botany)|stipe]]''' (as in ''[[Vanda]]''). These filaments hold the pollinia to the '''[[viscidium]]''' (sticky pad). The pollen are held together by the [[alkaloid]] [[viscine]]. This viscidium adheres to the body of a visiting insect. The type of pollinia is useful in determining the genus. On top of the pollinia is the '''[[anther cap]]''', preventing self-pollination. At the upper edge of the stigma of single-anthered orchids,

The [[reproductive organ]]s in the center ([[stamen]]s and [[carpel|pistil]]) have adapted to become a cylindrical structure called the [[column (botany)|column]] or gynandrium. On top of the column lies the [[Carpel|stigma]], the vestiges of stamens and the [[Pollinium|pollinia]], a mass of waxy [[pollen]] on filaments. These filaments can be a '''[[caudicle]]''' (as in ''[[Habenaria]]'') or a '''[[stipe (botany)|stipe]]''' (as in ''[[Vanda]]''). These filaments hold the pollinia to the '''[[viscidium]]''' (sticky pad). The pollen are held together by the [[alkaloid]] [[viscine]]. This viscidium adheres to the body of a visiting insect. The type of pollinia is useful in determining the genus. On top of the pollinia is the '''[[anther cap]]''', preventing self-pollination. At the upper edge of the stigma of single-anthered orchids, in front of the anther cap, is the '''[[rostellum]]''', a slender beaklike extension.

in front of the anther cap, is the '''[[rostellum]]''', a slender beaklike extension.

==Reproduction==  

==Reproduction==  

==Fruits and seeds==  

==Fruits and seeds==  

[[Image:Kapselquerschnitte Orchideen.png|thumb|right|200px|cross-section of an orchid capsule, showing 3 or 6 longitudinal slits]]

[[Image:Kapselquerschnitte Orchideen.png|thumb|right|200px|cross-section of an orchid capsule, showing 3 or 6 longitudinal slits]]

The orchid [[ovary (plants)|ovary]] is always inferior (located behind the flower), three-[[carpel]]ate and one or three-partitioned, with parietal [[placenta]]tion (but axile in the [[Apostasioidea

The orchid [[ovary (plants)|ovary]] is always inferior (located behind the flower), three-[[carpel]]ate and one or three-partitioned, with parietal [[placenta]]tion (but axile in the [[Apostasioideae]]).

e]]).

If pollination was successful, the sepals and petals fade and wilt but they remain attached to the ovary. The epigynous ovary typically develops into a [[capsule (fruit)|capsule]] that is [[dehiscent]] by 3 or 6 longitudinal slits, while remaining closed at both ends. The [[ripe]]ning of a capsule can take 2–18 months. The microscopic [[seed]]s are very numerous (over a million per capsule in most species). They blow off after ripening like dust particles or spores, barely visible to the human eye. Since they lack [[endosperm]], they must enter symbiotic relationship with mycorrhizal fungi to germinate. These fungi provide the necessary nutrients to the seeds.

If pollination was successful, the sepals and petals fade and wilt but they remain attached to the ovary. The epigynous ovary typically develops into a [[capsule (fruit)|capsule]] that is [[dehiscent]] by 3 or 6 longitudinal slits, while remaining closed at both ends. The [[ripe]]ning of a capsule can take 2–18 months. The microscopic [[seed]]s are very numerous (over a million per capsule in most species). They blow off after ripening like dust particles or spores, barely visible to the human eye. Since they lack [[endosperm]], they must enter symbiotic relationship with mycorrhizal fungi to germinate. These fungi provide the necessary nutrients to the seeds.

==Vanilla==

==Vanilla==

[[Image:Vanilla fragrans 2.jpg|thumb|250px|Vanilla fruit]]

[[Image:Vanilla fragrans 2.jpg|thumb|250px|Vanilla fruit]]

[[Vanilla]], ''Vanilla planifolia'' (and two other ''Vanilla'' species less commonly grown), is the only orchid which is grown for any other use besides its beauty (with a few minor exceptions).  Vanilla was first cultivated in [[Central America]] where it was used, like today, as a flavoring.  Vanilla cultivation was introduced to other parts of the world in the 1800s and it is now an important crop in much of the tropics.  [[Madagascar]] is the leading producer, producing in 2005, 3 million metric tons (of a world total of 7.3 million metric tons).   

[[Vanilla]], ''Vanilla planifolia'' (and two other ''Vanilla'' species less commonly grown), is the only orchid which is grown for any other use besides its beauty (with a few minor exceptions).  Vanilla was first cultivated in [[Central America]] where it was used, like today, as a flavoring.  Vanilla cultivation was introduced to other parts of the world in the 1800s and it is now an important crop in much of the tropics.  [[Madagascar]] is the leading producer, producing in 2005, 3 million metric tons (of a world total of 7.3 million metric tons).