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Orchid flowers are in one word, breathtaking. No one can disagree with this. What is also amazing is that no other plant family has as many different flowers as does the orchid family.
Within the Orchidaceae there are many types of specialisations. Amongst the best known are the structural variations in the flowers that encourage pollination by attracting particular species of insects, bats, or birds.
Did you know that most African orchids are actually white, while Asian orchids are most often multicolored? Some orchids can only grow the one flower on each stem, whilst other orchids can sometimes have more than a hundred flowers on a single spike!
The typical flower of an orchid is what is known in botanical terms as zygomorphic, i.e. bilaterally symmetric. Orchid flowers grow on racemes or panicles in the following types:
- basal -these are produced from the base of the pseudobulb. An example of this is in Cymbidium
- apical - these are produced from the actual apex of the orchid. This can be demostrated in Cattleya, and
- axillary - these come from a node lying between the leaf and the plant. A good example of this is in Vanda.
Basic orchid flowers are composed of thus:
three sepals in the outer whorl, combined with three petals in the inner whorl.
The medial petal is most often modified and enlarged (which is also then called the labellum or lip) which forms a platform for pollinators such as bats, birds or insects and lies near the center of the corolla.
Together, not including the lip, they are called tepals.
 The sepals actually form the exterior of the bud. In this stage they are green, but if the orchid blossom is purple, for example, then the buds can also show a purple tint. When the orchid flower finally opens, then the sepals become extremely intensely colored.
Sepals may even mimick petals such as is found in some phalaenopsis or even be quite distinct. In many types, the sepals are actually mutually different and most oftern resemble the petals themselves. It is often not easy to distinguish the sepals from the petals. The normal form of orchid flower can be seen in Cattleya, with the three sepals forming a triangle. Hhowever in Venus Slippers (Paphiopedilum) for example, the lower two sepals are actually concrescent - that is to say they are fused together into a synsepal - while the lip looks like a slipper. In Masdevallia all the sepals are fused into a calyx. In this kind of example the sepals are prominent, notably in lycaste orchids where the actual petals become diminished and inconspicuous.
The reproductive organs in the center (stamens and pistil) have evolved to become a cylindrical type structure called the column / gynandrium. On top of the column lies the stigma, the remains of stamens and the pollinia - which is a mass of waxy pollen on filaments.
These filaments are also known as a caudicle (as in Habenaria) or also a stipe (as in Vanda). It is these filaments hold the pollinia to the sticky pad known as the viscidium. The alkaloid viscine holds the pollen together and it is this viscidium that sticks to the body of a visiting insect.
The type of pollinia is often very useful in determining the genus. On top of the pollinia is whats known as the anther cap which prevents self-pollination. At the upper edge of the stigma of single-anthered orchids, is the rostellum - a slender beaklike extension that is found in front of the anther cap.
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