Close-up view of a hybrid Cymbidium
View of a Hybrid
by Brian Johnston (Canada)
orchid hybrids are grown in huge numbers to supply the cut-flower
trade. Their long spikes, containing many large, brightly
coloured flowers, often continue to bloom for two to three weeks.
They are also one of the most popular flowers for use in
corsages. Of course, many Cymbidiums
are available for use in outdoor landscaping, provided that one lives
in a suitable climate. No one would describe them as “shrinking
violets”, since these large, grassy orchids may have spikes up to a
metre in length, and blooms over 10 centimetres in diameter.
The natural habitats of this genus
are widespread, from mid-Asia through southeast Asia to Australia and
New Zealand. Wild Cymbidiums
may be terrestrial, meaning
that they grow in well drained ground locations, epiphytes, where they cling to
trees, or lithophytes where
they cling to rocks. Presently, most of the Cymbidium plants available to the
public are semi-terrestrial,
and are grown in greenhouses under carefully controlled conditions in
order to maximize their success rate.
genus name, is derived from the Greek word kymbe which translates to
boat. This refers to the hollow recess in the lip, or labellum of
The Cymbidium spike (or raceme) shown below is about 50
centimetres in length, and contains thirteen flowers. Its stem is
extremely sturdy, making macro-photography a pleasure.
In the spikes of other plants, the
flowers are usually oriented identically on the stem. In this
case however, note that many of the blooms are not perfectly
horizontal, and that one faces up.
Stems lack the small leaflets that
are frequently seen in other genera. In my plant at least, all of
the blooms are positioned on one side of the stem. The almost
parallel, green veins that are visible on the back of the flowers’
sepals, are less prominent on their front surfaces. In the image
on the right, the uppermost section of the flower’s stalk possesses
noticeable ridges, and has a slightly larger diameter. This is
the flower’s ovary.
Orchids normally possess an outer
whorl composed of three sepals (modified leaves that protect the
flower’s bud stage), and an inner whorl of three petals. Two of
the flower’s three petals are indistinguishable from the sepals .
The third petal is grotesquely transformed into the flower’s
distinctive, red-coloured trumpet. This unusual structure is
called the labellum or lip.
The labelled image below shows the
main parts of the Cymbidium’s
reproductive system. At the centre of the flower is a roughly
cylindrical projection called the column. (In this hybrid the
cross-section is actually more oval than circular.) This column,
(sometimes called the gynandrium
or gynostemium), contains the
male anther and female stigma. Covering the end of the column is
the white anther-cap which
will be discussed later. For fertilization to take place, an
insect must land on the labellum, climb into the throat, and up onto
the strangely tongue-like yellow platform beneath the column.
From this position it may dislodge the anther-cap to obtain access to
the pollen masses of the flower, or it may come into contact with the
Both sepals and petals are fleshy,
waxy, and almost translucent in bright light. Only the top,
banner-like sepal is rounded at its tip. All of the other sepals,
and the two wing-like petals are pointed at their tips.
The trumpet-shaped labellum is the
most colourful structure of the flower. The intricate pattern on
its surface probably evolved as an insect attractant. The image
at right below shows a highly magnified view of the labellum’s
surface. The yellow “dust” near the edge is pollen.
Two very high magnification
macro-photographs show this pollen more clearly. In the image on
the right, individual pollen grains can be resolved.
The labellum’s surface is covered
with many rod-like, almost transparent hairs that are concentrated in
the areas of the red spots and lines.
At the very edge of the labellum, a
slightly different type of hair can be seen. Many of these are
larger, and have a more rounded tip.
Immediately under the anther-cap
there is a tongue-shaped structure covered by an extremely large number
of fine, semi-translucent hairs.
A view of the very tip of the
tongue shows just how closely these hairs are packed on its surface.
The bulbous tips of the hairs
suggest that they are glandular in nature. Six images with
increasing magnification show the details of these glandular hairs.
As you can see below, the entire
top surface of the “tongue” is completely covered by hairs.
The underside of the “tongue”
however, has none.
Immediately behind the “tongue” in
the image below is the “front” of the orchid’s column. It is
yellow and pink in colour, and is covered with dark red spots.
The two macro-photographs below
show the column’s surface near its base. The surface appears
shiny, as though coated with liquid (nectar?).
Higher up the column, the
background colour transitions to pink, and the round spots become oval.
Much higher magnification of these
oval spots reveals interesting details.
The time has come to take a closer
look at the orchid’s reproductive structures. The tip of the
flower’s column curves down towards the labellum. This forms a
sort of hood under which the anther and stigma are located.
In the images below, the white
anther-cap can be seen to be divided into two almost spherical lobes by
a groove. On each side of the cap there is an arm-like projection
growing from the column. These “arms” may help to strip the
pollen mass from a visiting insect.
In order to see the structures more
clearly in the images that follow, the column has been removed from a
flower. Notice that from this angle, the anther-cap looks
remarkably like the head of an albino bird – beak and all! In
order for an insect to obtain access to the flower’s anther and pollen
masses, it must lift (or push) the beak upwards. The entire
anther-cap will then be dislodged, and the cap will fall away,
revealing the flower’s pollen masses. Under the beak in the first
image, there is what appears to be a white envelope-like structure that
is slightly open at the front. The interior of this structure is
the flower’s stigma.
A much higher magnification reveals
the strange surface appearance of the lobes of the anther-cap.
Each cell appears as a transparent liquid droplet! The white
structure beneath the anther-cap, as mentioned before, is the upper
surface of the stigma chamber.
Notice below, that the red material
that constitutes the end of the column wraps over the anther-cap like
the shoulders of a coat. Remember that there is no connection
between the “coat” and “cap”; an insect can easily dislodge the cap.
Here is what the column looks like
after the anther-cap’s removal The two bright yellow mounds are
the flower’s two pollen masses (pollinia)
looking remarkably like poached eggs! These packages of pollen
are sticky, and when an insect comes into contact with one of them, all
or part of the pollen mass adheres to a leg or part of its body.
If we move under the column shown in the first image, and look up, we
see the shiny receptive surface of the flower’s stigma.
Incredibly, the Cymbidium orchid
was written about in China and Japan before the time of Confucius
(551-479 BC). Today, due to the ongoing efforts of
horticulturists, these large, spectacularly colourful flowers are
The low magnification, (to 1:1),
macro-photographs were taken using a 13 megapixel Canon 5D full frame
DSLR, using a Canon EF 180 mm 1:3.5 L Macro lens.
An 8 megapixel Canon 20D DSLR,
equipped with a specialized high magnification (1x to 5x) Canon macro
lens, the MP-E 65 mm 1:2.8, was used to take the remainder of the
A Flower Garden of
A complete graphical index of all
of my flower articles can be found here.
The Colourful World of
A complete graphical index of all
of my crystal articles can be found here.
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Published in the
November 2010 edition of Micscape.
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