A Close-up View of the Chinese Pagoda Primrose
Close-up View of the
Chinese Pagoda Primrose
by Brian Johnston (Canada)
mist of primroses within her breast
This Primula vialii hybrid certainly
looks different than other Primroses! Perched atop a long
cylindrical stem, its two-toned, rocket-shaped flower-head has
brilliant red bracts, and orchid pink flowers. The plant
about 40 centimetres in height, and has a rosette of short,
shaped basal leaves. Other common names for this species
Foxtail Primrose, Poker Primrose, Orchid Primrose, and Wayside
The Primula genus of perennials
contains around 400 species, most of which are found in the
Hemisphere temperate regions. China and the Himalayas
greatest number of species, and Primula
vialii is in fact native to China’s Yunnan Province.
Images follow that show the
long stem, and two-toned flower-head.
Most leaves in the basal
are positioned vertically, and thus show their ‘back’ surface to
The ‘front’ of a leaf is
hairy and possesses a central longitudinal vein with irregularly
As can be seen below, each
an extremely concave ‘back’ surface, and strikingly toothed
The two images that follow
white ‘peg’ that forms the tip of each tooth along a leaf’s
Notice in the image at left
how prominent is the main vein on a leaf’s underside. It
extremely hairy. The photomicrograph on the right shows
the teeth along the leaf’s margin, and the bulbous-tipped
hairs that grow from its surface.
The cellular structure of one
the ‘pegs’ at the tip of a tooth can be seen in the image on the
Stomata and guard cells, which
control gas entry and exit from a leaf’s underside, are visible
Photomicrographs follow that
the segmented glandular hairs that grow from the veins on the
of a leaf.
Viewed from directly overhead,
glandular hairs appear as shaded spheres.
A leaf’s main vein is not
deeply in the undersurface of the leaf, but is very prominently
with minimum connection between vein and leaf.
The plant’s main stem has an
approximately circular cross-section, with a single, shallow
longitudinal groove on its surface.
Closer views reveal that the
is also liberally covered with short glandular hairs.
The following sequence of
taken with increasing magnification, shows a very early
flower-head. At this point the buds are still completely
protected by pale green bracts, (modified leaves). Near
of the flower-head, hints indicating the eventual red colour of
bracts have begun to appear.
A week later, these same
brilliantly red coloured on an almost white background. At
stage, no signs of the underlying flower buds are visible.
At the middle of both images
you can see the purple tips of bud petals peeking out from
bright red bracts.
If the surface of one of the
is examined under the microscope, its cellular structure becomes
Higher magnification reveals
While working with the plant,
noticed that most of the structures comprising the flower-head
covered with what appeared to be microscopic ‘snow
the microscope, these appear to be tufts of white fibrous
whose purpose is unknown.
The three images that follow
the flower-head in bloom. Flowers have five pink, pointed
fused at the base to form the corolla. At the centre of
flower, there is a group of yellow anthers. Note that the
the stem has been angled away from the viewer in order that he
can see into the recesses of the corollas. Normally, the
are angled downwards, preventing the reproductive structures
This normal orientation can be
in the images below. Note that each flower is attached to
stalk through the narrow tubular base of the flared
many images, the pure white tufts of fibrous material mentioned
can be seen coating the inner surfaces of corollas.
The cellular structure of the
surface of a petal is visible in the photomicrographs
the variable shape of pollen grains in the second image.
Closer views of the ring of
at the centre of each flower’s corolla can be seen in the images
follow. Some flowers possess six anthers, while others
have only five.
The image that follows on the
shows a portion of the tubular base of a flower’s corolla.
shadow is being cast by some internal structure. The image
right shows this structure – an anther joined to the wall of the
corolla by a short, remarkably small diameter filament.
The final views show more
magnified anthers with their variably shaped pollen grains.
The hybrid Primrose studied in
article, Primula vialii
Pagoda’, was awarded the Royal Botanical Society ‘Award
Garden Merit’ in 1993. It is indeed a spectacular plant!
Twilight hath folded up, and
Seeking remoter valleys long
Not yet hath come her sister
George William Russell
(1867 – 1935)
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 10 megapixel Canon 40D
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
The photomicrographs were
using a Leitz SM-Pol microscope (using a dark ground condenser),
the Coolpix 4500.
A Flower Garden of
A complete graphical index of
of my flower articles can be found here.
The Colourful World
A complete graphical index of
of my crystal articles can be found here.
Microscopy UK or their contributors.
Published in the
June 2012 edition of Micscape.
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