Close-up View of White Viper's Bugloss
White Viper's Bugloss
by Brian Johnston (Canada)
Books on wildflowers and weeds usually
mention that the flowers of Viper’s Bugloss, also known as
Blueweed, Blue Devil, Blue Thistle, Snake Flower and Viper’s Grass, are
blue in colour. Occasionally mention is made of rare white
flowers for this species. Although I kept a constant lookout
during the plant’s growing period, I had never come across one.
Over the years I have written two articles about the common blue
version, and this summer I finally found four white plants in an area
containing hundreds of the normal plants. I pass by this area
almost every day, and I am certain that the white plants did not bloom
in earlier years. Why they suddenly appeared is a mystery.
White Echium vulgare may be rare, but it
certainly is not as strikingly beautiful and photogenic as the blue
variety. Nevertheless I consider it a duty to provide this
article for purposes of completeness. Identical in structure to
the blue variety, the only difference is colouration. This
situation reminds me of the albino skin pigmentation in humans.
It is not just the skin colour that is different, but also the hair and
eye colour. All parts of these albino plants are muted in colour
as though someone had decreased the colour saturation in
As can be seen in the first image
in the article, the flower is funnel-shaped, with five shallow
lobes. Notice in the image below that flowers bloom one at a time
on each of the curved (like a scorpions tail – hence ‘scorpioid’)
racemes. (A raceme is a group of flowers connected to a stem
where each flower is connected to the stem by a stalk.) Also
notice that the flower’s stamens and pistil extend out beyond the
Buds appear on the lower scorpioid
Simply looking at the upper portion
of the plant’s stem, you might get the impression that the many green,
pointed bracts, (modified leaves), are covered with very fine,
down-like hairs. Warning
– that would be a big mistake! Each of those almost microscopic
hairs is a hard, fine, glass-like spine able to penetrate skin with
ease. Pulling a Viper’s Bugloss plant from the ground with your
hand would be a painful experience that you would never forget.
The first image below shows typical
Viper’s Bugloss buds. On the right is an image showing a
partially open flower.
The frothy bubbles on one of the
scorpioid racemes is created by an insect that, as children, we called
When viewed head-on, the raceme has
a V shape, with longer pointed green bracts framing two rows of shorter
bracts that hide the developing white buds.
Under a bud which is about to
bloom, there is a particularly long bract that dwarfs the others.
Projecting from the open mouth of
the flower are several of its bi-lobed anthers. As yet these
structures are not releasing pollen.
Under the microscope, the cells
constituting the petal’s surface are clearly visible.
In mature flowers the stamens, and
the single pistil project some distance from the front edge of the
Under the microscope, one of the
anthers has started to release its pollen, a process referred to as
Pollen grains appear to have an
If the surface of a dehiscing
anther is examined with higher magnification, sticky, thread-like
structures called viscin threads are visible. Usually, these
threads link the pollen grains together as they are expelled from an
If you look closely, it is possible
to distinguish the lower flower’s pistil in the image below. It
is colourless, and the stigma at its tip is forked (bi-lobed). On
the right is a photomicrograph showing the entire stigma.
Higher magnification views of one
of the two lobes, show that its tip is covered with receptive,
The plant photographed for this
article remained on a table for three days. Two insects seemed to
have made the upper stem of the plant their permanent home, since every
time I investigated they were happily doing whatever insects do –
eating I suppose.
For anyone who has touched a
Viper’s Bugloss plant, the most important structures are its pain
inducing spines. Essentially every surface except the petals are
covered by these glass-like needles.
Higher magnifications show their
structure and speckled surfaces.
Finally, here are a few additional
images of my insect ‘friends’. They seem unaffected by the forest
of lethal spines that constantly surround them.
Back in the mists of time Viper’s
Bugloss was thought to be able to expel poisons and venom from the
human body, and to cure viper bites. It is because of this
dubious ability that it was given the common name Viper’s
Bugloss. One early writer stated that “Viper’s Bugloss hath its
stalks all to be speckled like a snake or viper, and is a most singular
remedy against poyson and the sting of scorpions.” How fortunate
we are that we live in an era where the scientific method informs
doctors, rather the appearance of the remedy!
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.
A 10 megapixel Canon 40D 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
The photomicrographs were taken
using a Leitz SM-Pol microscope (using a dark ground condenser), and
the Coolpix 4500.
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.
Microscopy UK or their contributors.
Published in the
October 2011 edition of Micscape.
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