Close-up View of Deadnettle Hybrid 'Purple Dragon'
Deadnettle Hybrid 'Purple Dragon'
by Brian Johnston (Canada)
This colourful, and very attractive
plant, grows to a maximum height of about 20 centimetres and is
perfect example of the phrase “Good things come in small
packages”. Its many deep purple-red flowers contrast
with the silvery-green leaves. In suitable climates, the
an evergreen; unfortunately, the climate where I live is
extremely unsuitable one!
Leaves are dark green around
edge, silvery in the interior, and have purplish spots randomly
sprinkled over the surface. It may be for this reason that
its common names is the spotted deadnettle.
Groups of buds grow from the
axils, and the example shown is at a very early stage of
(about 3 mm in diameter).
When a group grows a bit
becomes possible to see the five spiky sepals surrounding each
bud. No colour is apparent at this stage.
Eventually, each bud appears
small white sphere nestled in a depression, and surrounded by
pointed lobes of the fused sepals.
In the image below, there are
rings of sepals, the upper one, with buds, and the lower
After blooming the entire corolla and reproductive structures
away, leaving the developing seeds at the base of the sepal
Closer views of the
buds reveal that they are completely covered by very fine hairs
make the bud look furry.
Now the buds begin to take on
pink colouration. Notice the tiny colourless insect in the
Conventional wisdom suggests
the ‘beauty’ of a plant is centred in its flowers.
is undoubtedly true, the bud stage sometimes gives the flowers a
run at overthrowing that wisdom. If you look carefully, in
of the images you can detect the unfurled ‘hood’ that will
become the tall, overhanging petal in the final blooming
Note that at this stage, the bud has finally grown out beyond
tips of the sepals.
maculatum flowers grow in clusters at the tips of
The flowers are remarkably similar to those of the snapdragon
upper of the five fused petals is particularly well developed,
hangs above the rest of the flower like a hood.
A side view of the flower’s
reveals the two lobes that form a ‘tongue’ at the front of the
flower. Just beneath the hood are the reproductive organs,
stamens and pistil.
The bright white base of the
corolla tube curves elegantly into the green cup formed by the
At the distance viewed in the
images below, it is just possible to resolve the four stamens
single forked pistil beneath the hood. Later we will see
clearer views of these structures.
As mentioned earlier, all of
bud, and petal surfaces are particularly hairy (hirsute).
Photomicrographs showing these
hairs can be seen below. The third image shows the tiny
that cover their surfaces.
Only if a flower is observed
below are its reproductive structures visible.
Each flower possesses four
anthers covered with yellow pollen. The filaments
these anthers are joined to the top of the fused section of the
tube about at the point where the colour changes from red to
A closer view of an anther
the fringe of colourless hairs that ring its dark body.
Side views show the point of
connection of the filament to the anther.
A slight change in focus gives
partial view of the flower’s stigma (white – pointing down in
At the point where the hood
the top of the corolla tube, there are two ‘shoulders’.
the white, hanging, thread-like structure that is positioned at
point of each shoulder. These structures also occur on
species of orchids.
The images that follow show
four anthers in a flower from different points of view.
Photomicrographs follow that
side views of an anther.
Higher magnifications allow
views of ellipsoidal Lamium
pollen grains on the surface of an anther.
Photomicrographs showing a
of grains on a microscope slide reveal surface details including
longitudinal groove that bisects each grain.
The upper portion of the
filament, which supports an anther, is also pollen covered.
In the image on the left, one
colourless, pointed lobe of the flower’s stigma is just
Other blooms, like the one shown on the right, have their
structures positioned deeper within the hood.
Since the pistil has a colour
similar to nearby structures, it is often difficult to
forked stigma against the background.
Removing the hood makes it
(somewhat) easier to see the flower’s pistil. Notice that
stigma’s position is roughly level with the anthers, which
increases the possibility of self-pollination. The base of
long supporting style is connected to the ovary positioned at
bottom of the corolla tube.
Stigmas in most flowers have
hair-like projections that help to capture pollen grains.
seems not to be the case in this species based on the
at right, below.
Plant stems are sturdy, and
relatively deep grooves along their length. Fine hairs
profusely on their surfaces.
maculatum’s shallowly lobed, heart-shaped leaves are
one of the
plant’s most admired details. Silvery-green, with a darker
edge, they have a complex and interesting vein pattern.
random, reddish-brown areas are attractive, although I believe
they may be signs of a problem.
Closer views of the upper
of one of the leaves can be seen below.
The cellular structure of a
upper surface is visible in the two photomicrographs that
Below are photomicrographs
the hairs growing from the lower surface of a leaf.
This strange looking sucking
was feasting on the leaf while I was working with it. Its
was so small that even looking carefully with the naked eye, it
This deadnettle cultivar is
groundcover in partly to fully shaded areas. Although its
are not large, the overall impression given by the plant is
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.
A 10 megapixel Canon 40D 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
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
March 2013 edition of Micscape.
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