Anatomy of an Orchid Flower
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            The structure of orchid flowers is unique among floral plants. The orchid flower is typically has an outer whorl of three sepals, an inner whorl of three petals, and a single large column (the gynostemium, composed of the male stamens attached to the female pistil) in the center.

            The sepals are the protective cover of the flower bud. When the flower opens, the sepals may become enlarged and colored. In most species, the sepals are equal sized and look like petals. In some species, however, the top, or "dorsal" sepal becomes very large and showy, the two lower "lateral" sepals are sometimes fused into one structure, and in other species all three sepals are fused forming a bell-shaped structure around the flower. In some species, the display of the sepals completely overwhelm the actual flower.

            The two lateral petals flank the greatly enlarged flamboyant bottom petal (lip or labellum) which is usually highly modified to attract and, in some cases, trap potential pollinators. The lip may be differently colored or marked, ruffled or pouch shaped, decorated with crests, tails, horns, fans, warts, hairs, teeth, or other decorations attractive to their selected pollinator.

            The orchid's reproductive organs are combined into a single column (a gynostemium) unlike the usually separate male stamen/anther and female pistil/stigma configurations of other flowers. This is the primary identification feature of an orchid. At the top of the column is the male anther which contains packets of pollen called pollinia. Below the anther is the stigma, a shallow, usually sticky cavity in which the pollen is placed for fertilization. There is a small growth, called the rostellum which acts as a protective barrier to prevent self pollenation. Some species produce separate male and female flowers to prevent self pollenation.

            The overall flower shape is characteristically bilaterally symmetrical (the left and right halves of the blossom are mirror images), a necessity for reliable pollenation by bees.

            In the bud stage, the lip is the uppermost petal. In most (but not all) orchids, as the flower opens, the flower twists 180 around its flower stalk to position the lip on the bottom. This unique process is called resupination. Some orchid flowers remain "upside down" or non- resupinate while other flowers will rotate in a complete 360 circle ending back in the original upside position!

            Many tropical species of orchid will rely on a single species of euglossine bee to pollinate them, and the bee will visit only that particular species of orchid. Some orchid species have established pollinator relationships with flies, gnats, moths, butterflies, hummingbirds, and even bats!

LAELIA
1. Sepals - Although they may look like petals, they are actually the glorified remains of the flower bud. There are usually three of approximately equal size.

2. Petals - Orchids always have three petals. Two are "normal," and the third becomes a highly specialized structure called a lip.

3. Lip or Labellum - The lower petal of an orchid. Used by the flower to provide a 'landing platform' for its pollinator.

4. Column - A finger-like structure that carries the orchid's reproductive organs--the stigmatic surface (female organs) and the pollinia (male organs) located under the anther cap (operculum).

(Lc Kevin Green 'Margie' X Lc California Nuget 'Susan')


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CATTLEYA
1. Sepals - Although they may look like petals, they are actually the glorified remains of the flower bud. There are usually three of approximately equal size.

2. Petals - Orchids always have three petals. Two are "normal," and the third becomes a highly specialized structure called a lip.

3. Lip or Labellum - The lower petal of an orchid. Used by the flower to provide a 'landing platform' for its pollinator.

4. Column - A finger-like structure that carries the orchid's reproductive organs--the stigmatic surface (female organs) and the pollinia (male organs) located under the anther cap (operculum).

(C. Mt Hood 'Dilworth')


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PAPHIOPEDILUM
1. Sepals - Although they may look like petals, they are actually the glorified remains of the flower bud. There are usually three of approximately equal size, but not always. The two lateral sepals are fused into one and the dorsal (top) sepal is greatly enlarged in the case of the paphiopedilum and others.

2. Petals - Orchids always have three petals. Two are "normal," and the third becomes a highly specialized structure called a lip.

3. Lip or Labellum - The lower petal of an orchid. Used by the flower to provide a 'landing platform' (or a trap, in this case) for its pollinator.

4. Column - A finger-like structure that carries the orchid's reproductive organs--the stigmatic surface (female organs) and the pollinia (male organs) located under the anther cap (operculum).

(Paphiopedilum virens)


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The Orchid Lady's Orchid Encyclopedia
Copyright 1996-2002 Linda Fortner. All rights reserved.
Contents may not be copied or reproduced without prior permission.

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