Close-up View of the Hybrid
Delphinium 'Guardian Blue'
by Brian Johnston (Canada)
Over the past few years, I have searched
in vain for an exceptional Delphinium to photograph for a Micscape
article. Finally, during a recent trip to my local greenhouse I
noticed, behind a large grouping of white examples, this single,
extremely colourful plant. My search was finally over!
The cultivated Delphinium, (a
member of the Ranunculaceae,
or Buttercup family), possesses long, showy racemes containing variously
coloured spurred flowers. (A raceme is an unbranched, elongated
flower cluster in which each flower is attached by its stalk directly
to a central stem.) Delphiniums are often referred to as Larkspurs, although this
appellation is also used by the related genus Consolida. The genus name Delphinium derives from the Greek delphinion which refers to the
dolphin–like shape of the bud.
elatum ‘Guardian Blue’ possesses the strikingly colourful
flowers seen above. The small central petals are white, and they
are surrounded by rings of larger, patterned, purple petals. A
whorl of mottled blue and purple petals provides the background.
The 25 centimeter long flowerhead
begins to bloom at the base of the raceme, and about a week is required
for the process to be completed. The overall height of the plant
is about one metre.
A closer look at the unopened buds
reveals that they do rather look like fat dolphins (or tadpoles),
except of course for their colour! Notice that a spike-like green
leaflet grows from the point of connection of each bud’s stalk to the
The two views that follow show an
unopened bud with its spur (left), and a later stage bud in the process
of opening (right).
Mature flowers are about 3
centimetres in diameter, and are usually so tightly packed in the
raceme that they obscure the plant stem completely. Note, at the
top of the two images, the two smaller blooms that are in the process
These two flowers can be seen more
One of the main reasons for
choosing this particular hybrid is the intricate colour pattern
possessed by its petals. The image at right below, shows that
this pattern is reminiscent of a stained-glass window.
If we use the microscope to take a
closer look at one of the blue petals from a flower’s back whorl, it is
obvious that its surface is very three-dimensional. Near the
centre of the right-hand image there is a very tiny, pearl-like sphere
on the end of a fragile stalk. I have no idea of the purpose of
Near the tip of a similar, less
mature petal, there is an area with greenish colouration.
Photomicrographs showing the
pigmented cells within this section of petal appear below.
A higher magnification
photomicrograph of the cellular structure is again reminiscent of a
Between the green and blue areas of
still another petal, there exists a pinkish colouration.
Low and higher magnification images
of the cells in this area can be seen below. The image on the
right hints that the entire cell is not coloured. Instead, there
appears to be a thread-like internal structure which possesses colour.
Now let’s look at one of the large
pink petals from the front of a flower. Again, the surface is
It is very evident from the
photomicrographs below, that a cell’s colouration is due to multiple
pigmented, tangled filaments within the body of the cell.
As was mentioned before, the
Delphinium flower has several rings or whorls of petals. The
front-most whorl consists of four rather small, ribbon-like white
petals with a purple radial band. Beneath this whorl is a second,
and third, each of which possesses larger, roughly oval pink
petals. Finally, the rear whorl possesses even larger oval petals
with pink centres and deep blue edges.
At the flower’s centre, the whorl
of ribbon-like petals frame its reproductive structures.
In many other species, these
reproductive structures are organized in an orderly arrangement.
This is certainly not the case in the Delphinium!
Stamens and pistils appear to be in
a completely random arrangement.
Closer views reveal that anthers
(male pollen producing organs) are at first covered by green and yellow
‘caps’. Later, these caps disintegrate to reveal the actual
brown, pollen covered anthers.
photomicrographs of two anther-caps show their cellular structure, and
the pollen grains that have fallen onto them from mature anthers.
By removing most of the petals from
a Delphinium bloom, it is possible to see just how disorganized is the
group of anthers and their supporting filaments.
One such anther and filament can be
seen in the photomicrograph below.
If some of the stamens are removed
from a flower, the large number of pistils, (each composed of stigma,
style, and ovary), can be seen. The stigma and style are white,
while the ovary is bright green.
The unusually shaped tip of a
stigma can be seen below.
The surface of the ovary has many
pollen grains adhering to it.
Pollen grains are roughly
ellipsoidal in shape.
The striking beauty of the
Delphinium hides a darker side. Although insects fertilize the
flowers, and the larvae of some Lepidoptera species eat leaves and
stems, the plant is very toxic. The seeds are the most
poisonous. Foliage is less toxic, and toxicity decreases as the
plant ages. Toxicity is due to the presence of a number of
alkaloids including delphinine, delphineidine, and ajacine.
Delphinium’s dried, ripe seeds contain calcatripine, as well as gallic
and aconitric acids. Absorption of these compounds through the
skin may cause poisoning through excessive handling.
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.
An 8 megapixel Canon 20D 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 (with a dark ground condenser), and the
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 June
2009 edition of Micscape.
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