A Close-up View of a Lady's Slipper Orchid
Close-up View of a
Lady's Slipper Orchid
by Brian Johnston (Canada)
article focuses on another hybrid
Lady’s Slipper orchid with a more flamboyant structure, but less
colourful appearance than the first.
Most Paphiopedilum orchids are terrestrial, meaning that
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 using Paphia, one of the surnames
Aphrodite, and pedilon
meaning a sandal, the genus translates to “Aphrodite’s sandal”.
in reference to the bulbous pouch which is the orchid’s
Most of the Lady’s Slipper
that I have seen possess long thin stems that hold the flower(s)
above the rosette of leaves. This particular hybrid, for
reason, had such short stems that the flowers nestled amongst
leaves. Both the white dorsal sepal, and the two yellowish
petals, have subtle structural details that make this hybrid my
favourite of the three that I have photographed.
Many Paphiopedilum orchids have mottled,
or patterned leaves; however this one has undecorated ones, each
bisected by a deep crease.
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. Two of the three
can be seen as the wavy-edged wings that angle down from the
centre. The third petal is grotesquely transformed into
flower’s distinctive pouch. This deformed, slipper-like
petal is called the labellum
or lip of the orchid,
we will see later, it plays an important part in the
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 be caught in the trap.
Unfortunately for the insect,
inside of the pouch is lined with shiny, slippery cells – except
location! On the interior dorsal wall (the back of the
there exists a “ladder” composed of tiny upward pointing
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. (In the image below, if you look inside the pouch
immediately below the staminode, the location of the climbing
The three images that follow
(with increasing magnification), the upward-angled hairs that
insect in its escape from the pouch via the back wall.
Views of a flower’s dorsal
show its ornamental shape, and curious spotting. Although
background colour is white over most of its surface, near the
changes to light green.
The shield-like staminode that
hides the flower’s reproductive structures is shaped like an
heart in this hybrid. The yellowy-orange, nose-like
near its centre gives the staminode a vaguely “fried egg”
Except near its “nose”, the
staminode is coated with fine, purple hairs. These hairs
in density near its connection to the column. In both
flower’s white stigma peeks out from under the staminode’s
The column holding the
reproductive structures can be seen in the two views that
Near the base of the column, the hairs are much longer, and have
greater diameter. In both images, one of the bloom’s two
is visible just to the right of the staminode.
The image below shows the
positions of the male and female reproductive organs in the
Slipper orchid. Each anther is attached to the column by a
horn or “hanger”. Immediately below the anthers is the
disk-shaped, white stigma with its active surface facing down,
from the anthers.
In Paphiopedilums, the pollen is held
in a waxy, fairly undefined mass with the consistency of mealy
beeswax. In the images below, this mass of pollen is
yellowish-white with a bright red outer layer. The shiny
brownish-yellow material attached to the outermost region of the
mass, is called the anther cap.
sticky, waxy cap is what gets stuck to the leg or body of an
insect as it brushes against the structure. As the insect
away, it carries the cap, and the attached pollen mass with it –
perhaps to the stigma of this flower, or perhaps to the stigma
nearby flower of the same species. Self-fertilization
the result of the first possibility, and cross-fertilization the
of the second. Of course, cross-fertilization is preferred
the long-term well-being of the species.
In this hybrid, each anther is
bi-lobed. The second image shows why it is so easy for the
to be carried away by an insect that comes into contact with the
cap. The point of connection of the anther to its “hanger”
appears relatively weak.
As an insect climbs out of the
labellum “trap” it “sees” the bottom (active) surface of the
Orchids can be found growing
of Earth’s continents, except Antarctica. Over the
80 million years that they have existed, their flowers have
attract, deceive, and manipulate insects in order to maximize
possibility of fertilization. Lady’s Slipper orchids are
examples of one such strategy.
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
December 2011 edition of Micscape.
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