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Many varieties of the orchid can be grown fairly easily in a common
windowsill. Others require a good deal of humidity to grow properly. It is
not true that one needs a greenhouse to grow orchids. Many orchids even grow
well without a greenhouse given proper light and water. In nature, orchids
can be divided into four types according to growing conditions. Most are
classified as epiphytes found in tropical moist broadleaf forests or
mountains and subtropics. These are anchored on other plants, mostly trees
and shrubs. The rock growers, or lithophytes, cling to the surfaces of
rocks. Saprophytes are those that grow in mulch, often on the forest floor.
Finally, there are the dirt growers, or terrestrials, which anchor
themselves in soil or sand. A few are lithophytes, similar to epiphytes but
growing naturally on rocks or on very rocky soil. They derive their
nutrients from the atmosphere, rainwater, litter, humus and even their own
dead tissue.
The structure of the leaves corresponds to the specific habitat of the
orchid. Species that typically bask in sunlight have thick, leathery leaves.
The laminas are covered by a waxy cuticle. These retain their necessary
water supply. For shade species, the leaves are tall and thin. 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 some species can be most beautiful. For example, the leaves of
the Macodes sanderiana, a semiterrestrial or lithophyte, show a sparkling
silver and gold veining on a light green background.
The sepals form the exterior of the bud. They are green at this stage,
but sometimes, if the orchid blossom is purple, the buds can show a purple
tint. When the flower opens, the sepals become intensely colored. In many
orchids, the sepals are mutually different and generally resemble the
petals. It is not always easy to distinguish sepals and petals. The
reproductive organs in the centre have adapted to become a cylindrical
structure called the column. On top of the column lies the stigma and the
pollinia, a mass of waxy pollen on filaments.
If pollination is successful, the sepals and petals fade and wilt but
they remain attached to the ovary. The ovary typically develops into a
capsule. The ripening of a capsule can take 2-18 months. The microscopic
seeds 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.
Orchids are indeed some of the most beautiful flowers in the world.
Breeding them can be a highly challenging endeavor. It needs a lot of
patience because the orchid seeds are characteristically small and mortality
rate of both the seeds and the sprouts is high. The National Orchid Garden
in the Singapore Botanic Gardens is considered by some to be among the
finest collections of orchids in cultivation open to the public. The Taiwan
Orchid Plantation was set up to develop commercial orchid exports in the
future.
Orchids have become a major market throughout the world. Buyers now bid
hundreds of dollars on new hybrids or improved ones. Due to their apparent
ease in hybridization, they are now becoming one of the most popular
cut-flowers on the market. Though orchid hybridization has been happening
for many years, only recently has new technology made it into what it is
today. |
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Based
on the passage given, write a summary on :
•
where orchids are grown
•
their characteristics
Your
summary must:
• be
in continuous writing ( not in note form )
• not
be longer than 130 words, including the 10 words given below
Begin
your summary as follow:
Orchids are divided into four types. They are epiphytes found ... |
