A Close-up View of a Lady's Slipper Orchid hybrid
Close-up View of a
Lady's Slipper Orchid
by Brian Johnston (Canada)
article focuses on still another
hybrid Lady’s Slipper orchid, this one with a restricted colour
consisting of white and shades of green. An earlier article
be found here looked at more colourful Paphiopedilum
Most orchids of this genus are
that they grow
in well drained ground locations, rather than clinging to trees
(epiphytes), or rocks (lithophytes).
All Lady’s Slipper orchids
to the Cypripedioideae,
sub-family of the Orchidaceae.
differ from the rest of the orchids in that they possess two
anthers instead of the usual one. Although in many
petal forms a landing platform for insects, here it is
an elegant, and very distinctive pouch-shaped insect trap.
The Paphiopedilum genus was established
by Ernst Hugo Heinrich Pfitzer in 1886. Generated
one of the surnames of
Aphrodite, and pedilon
meaning a sandal, the genus translates to “Aphrodite’s sandal”.
in reference to the bulbous pouch which is the orchid’s
As you can see from the
below, this orchid’s stem was not strong enough to support the
the flower, and required assistance.
The stem has a round
and is completely covered with very fine hairs.
Orchids normally have an outer
whorl composed of three sepals (modified leaves that protect the
flower’s bud stage), and an inner whorl of three petals. Paphiopedilums however, are
different. The distinctive banner-like structure at the
the flower is the dorsal sepal. The other two sepals are
and are fused together to form an apron-shaped structure that is
behind the pouch at the flower’s base. This structure, referred
the synsepal, hangs
the point where the flower’s stem-like ovary meets the
Notice that like the dorsal sepal, it too is white with green
stripes. Two of the flower’s three petals can be seen as
striped green wings that angle down from the flower’s
third petal is grotesquely transformed into the flower’s
pale green pouch. This unusual structure is called the labellum or lip.
A closer view of one of the
reveals the randomly spaced bumps that grow along its
rotated image of the central area of a petal shows its raised
and cellular detail.
Additional rotated images show
magnified views of these bumps, and the many almost transparent
that grow along a petal’s edges.
In this hybrid, although the
dorsal sepal angles forward, its tip curves in the reverse
direction. The sepal itself is composed of translucent
is quite different in substance from that of the petals, which
be more leathery. The light green “veins” or “ribs” are
considerable distance above the white tissue of the rest of the
By adjusting the lighting
the three-dimensionality of the raised ribs is accentuated.
Here the magnification has
increased to the point where individual cells can be seen.
Two images follow that show a
reverse view of the base of the dorsal sepal. The image on
left shows that a very short stalk connects the flower to the
larger diameter ridged ovary.
Before we look at the
strategy of the Paphiopedilum
orchid, a little terminology must be understood. Both the
flower’s male, and female reproductive organs are held at the
end of a
rod-like structure called the column
(or gynostemium), which
extension of the stem and ovary. Two fertile anthers are
to the column, one on either side. A curiously modified
anther, this one infertile, is located at the end of the
Looking somewhat like a shield, it is called the staminode. Also
the column, but hidden behind the staminode, is the flower’s
stigma. The relative positions of all of these
structures can be seen in the diagram and image that follow.
Since the anthers and stigma
hidden behind the staminode, a visiting insect cannot see
In other orchid species, the labellum provides a landing place
proximity to the reproductive parts - not here however.
searching for nectar, an insect may fall into the Paphiopedilum’s pouch, and
caught in the trap. Unfortunately for the insect, the
the pouch is lined with shiny, slippery cells – except in one
location! On the interior dorsal wall (the back of the
there exists a ladder made up of tiny hairs that point
Only here can the insect escape in the same way a wall climber
using the projections that are provided for that purpose.
the insect reaches the top of the labellum, it is very
positioned immediately below one or other of the anthers, and
stigma. Notice in the two images that follow, how the
the back of the labellum curve inwards to produce a vertical
that funnels the climbing insect into the correct
shield-like staminode is outside of the tunnel, but the stigma
greenish-white disk) is within the tube formed by the back of
If the labellum is removed
flower, it becomes easier to see the disk-like stigma.
the stigma’s receptive surface faces down, and is not visible in
images. The staminode is certainly artistically shaped!
The strange nose-like
at the bottom of the staminode, and the many fine hairs that
staminode’s surface, can be seen in the higher magnification
Notice in the image on the
below, how effectively the curved back surfaces of the labellum
an insect up towards the flower’s two anthers. The
of the labellum’s surface on the right shows its subtle veining,
shiny surface texture.
In the higher
images of the orchid’s anthers that we will see later, it is not
obvious that the anthers are bi-lobed. This fact can be
clearly however in the right-hand image below.
Each anther is attached to the
column by a small horn or “hanger”. In Paphiopedilums, the pollen
in a waxy, fairly undefined mass with the consistency of mealy
beeswax. In the images below, this mass of pollen is pale
and a section of a sphere in shape. The light brown
attached to the outermost region of the pollen mass, is called
the anther cap.
Between the anther
cap and the pollen mass there is a bright red layer. The
waxy cap is what gets stuck to the leg or body of an insect as
brushes against the structure. As the insect moves away,
carries the cap, and the attached pollen mass with it – perhaps
stigma of this flower, or perhaps to the stigma of a nearby
the same species. Self-fertilization would be the result
first possibility, and cross-fertilization the result of the
second. Of course, cross-fertilization is preferred for
long-term well-being of the species. (In both images, the
staminode is in the upper right corner, while the stigma, which
down, is at the bottom.)
The two views that follow show
hanger, and its attached pollen mass.
When photographed from an
angle, the receptive surface of the orchid’s stigma
Notice that the base of the
hybrid’s ovary is cupped by a leaflet. It’s the bottom of
leaflet that marks the end of the plant’s stem, and the
The flower’s ovary is pale
with raised, deeper green, longitudinal ridges. Its
Many, but not all Paphiopedilum orchids have
or patterned leaves. The one shown below belongs to the
Slipper Orchid studied in this article.
Details of the mottled
the leaf’s microscopically bumpy surface texture can be seen in
high magnification images below.
The Chinese and Japanese
began writing about orchids a couple of thousand years
the last few centuries, these unique flowers were actively
at first by gardeners of the wealthy aristocracy, and later by
interested in monetary gain. It’s believed that there may
than 35 000 orchid species, and in addition, many hybrid
the one shown in this article.
The low magnification, (to
macro-photographs were taken using a 13 megapixel Canon 5D full
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
lens, the MP-E 65 mm 1:2.8, was used to take the remainder of
Microscopy UK or their contributors.
Published in the
January 2012 edition of Micscape.
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