ORCHIDS

ORCHID --PHALAENOPSIS

Orchids are the world's most glamorous flowers and there is no doubt about that. Like other perennials plants, they are also specially grown to enable the pollination. The years gone by when they were labelled as having mystical powers as well as parasites or carnivores. However, over the centuries they came from bottom to the top and are now regarded are the most exotic flowers.

Today you can count 18,000 different species of orchids and they found their way all over the world apart from the most extreme habitats. They grow on the damp mountains of Norway and New Zealand; in shady forest of Europe; on heathlands and marches of North American. Nevertheless, most of the orchids are found in the tropics. The ones growing on the ground are known as terrestrials. Some grow high in the leafy canopy of forests and they are known as epiphytes.

All orchids are perennial plants in spite of the wide variety but they split into two categories.

SYMPODIAL ORCHIDS grow very much as the herbaceous perennials. Their leaves and flowers grow from the base of previous growths. These type of orchids grow 'pseudobulbs' to prevent drying out in a seasonal drought. Pseudobulbs are swellings on the stem and it contains food and water. Other pseudobulbs are club-shaped on the cattleya orchids and some are long, thin and up to a meter longcane-like pseudobulb like on the Dendrobium orchids. Most of the pseudobulbs are egg-shaped and between a few millimetre to almost 20 cm.

CEOLOGYME CRISTATE grows, what looks like a bunch of grapes, pseudobulbs. When the leaves are shed from the old pseudobulbs the store of nutrients provides food for the new growth.

MONOPODIAL ORCHIDS grow from the previous years' growth and therefore the plant grown upwards. The new leaves grow alternatively on opposite sides from the top. Some of the most beautiful orchids is called VANDA GENUS and grows in China, the Himalayas, New Guinea and Australia. They are epiphyte orchids meaning they grow erect leafy stems, evergreen leaves, strong-coloured flowers on long stems and long aerial roots to secure itself to the trunk or branch of the tree. Some aerial roots just tangle down to get the moisture and nutrients through porous layers. These roots can reach a length of 1.2 meters and store water and nutrients.

CROSS-POLLINATION

There is an amazing fact that orchids do anything to get their flowers cross-pollinated.  Many of them have evolved in conjunction with one specific insect pollinator, changing their  structure to fit the size and shape of these partners. 

Scent is one thing they use to attract pollinators.  A fine example is the Angreacum orchids from tropical Africa.  They waft scents at dusk into the air to attract moths.  The moth drinks its nectar and picks up a sac of pollinia with its head.  On a visit to the next orchid, the moth transfers the pollonia to the stigma of that orchid and cross-pollination happened.  The orchid develops a fruit-capsule and a single spike of flower can produce up to a million of seeds.  Seeds take two to 18 months to ripen and the same time to germinate.  The plant could take up to four years to flower or more and produce seeds

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