Close up view of a bleeding heart cultivar
Bleeding Heart Cultivar
by Brian Johnston (Canada)
Bleeding Hearts are shade garden and
woodland plants that have a variety of alternative names such as
Dutchman’s Breeches, Dutchman’s Trousers, Venus’s Car, and Lyre
Flower. The cultivar studied here, ‘Burning Heart’, is a
introduction which forms 30 centimetre high mounds of fern-like
and deep red flowers.
It should be kept in mind that
members of the Dicentra genus
cocktail of poisonous compounds such as
isoquinoline-like alkaloids. Aporphine, protoberberine,
than 20 compounds structurally related to poppy alkaloids have
found in various Dicentra species.
As can be seen in the first
in the article, and the two that follow, the flowers in a raceme
from their stalks (are pendulous), and are shaped like hearts
downward pointing protuberances which are thought to represent
blood. (This accounts for the ‘bleeding’ part of the
Unlike the plant’s mature
its early stage buds are held upright by their short stalks and
stem holding the raceme. (A raceme is a group of flowers
emanating from a single stalk in which each individual flower
own stalk.) Only hints of their final colour can be
photographs taken at this point.
As the buds increase in size,
red colouration extends farther, and the stem holding the raceme
to droop. Notice that the heart-shaped portion of the bud
develops more slowly than the blood-drop protrusion.
My local Garden Centre
gave me ‘value added’ along with this Bleeding Heart
I got it home, I was surprised to find that it was crawling
with tiny green aphids. They played hide-and-seek with me
took the first day’s photographs. I would position the
so that no aphids were in view, and the moment I grabbed hold of
remote shutter release, they would spring into view. That
I took special delight in killing all of them by spraying the
liberally with ‘Raid’. The paper towels on which the plant
placed were covered with dozens of the little pests’
If a section of one of the
petals is examined under the microscope, its cellular structure
visible. (In order to increase contrast, I utilized
‘Levels’ function. This results in the images being
A much higher magnification
photomicrograph of a section of one of the flower’s curved
shows a cellular structure reminiscent of a stained glass
Dicentra flowers have a rather
unusual structure. There are 4 petals, two outer that form
‘heart’, and two inner that form the projecting ‘blood-drop’
projection. The outer petals are fused at the base forming
are referred to as two basal sacs, and free at the backward
ends. The inner petals are slender at the base, and
through the basal sac structure. These long petals are
forming a crested hood that encloses the flower’s stamens and
The three images that follow
the curved tip of one of the outer petals. Notice that the
revealed ‘inner’ surface is colourless around the edge and deep
at its centre. The first image also shows the crested hood
covers the flower’s reproductive structures. (The remains
of the aphids killed by the ‘Raid’ can be seen stuck to the
surface in the last image.)
If both stamens and pistil are
covered by this crested hood, how do insects obtain access to
them? The answer can be seen in the image below. A
narrow longitudinal slit runs the length of the inner petal tube
both sides. If you look carefully at the top of the slit,
see evidence of yellow pollen grains on anthers. Insects
long legs or a proboscis can probe through the slit to obtain or
deposit pollen grains in the search for a flower’s nectar.
Removing one of the flower’s
petals allows one to see the tightly packed reproductive
Six anthers are connected to a
composed of the six fused, colourless filaments. The
stigma is positioned at the centre of the ring formed by the
pollen covered anthers.
Higher magnification reveals
tight packing of these structures.
When both inner petals are
from the flower, over time the anthers separate and give a
of the bi-lobed stigma. Since under normal conditions
petals remain in position, it is not possible for the separation
After several hours, the
pale green style which supports the stigma becomes
appears that several anthers are connected by short filaments to
Under the microscope, details
the structure of an anther become clearer. So many pollen
cling to each anther that its apparent width is almost
The last image shows the spherical shape of pollen grains.
The female reproductive
(stigma) has two prominent horn-like lobes.
Photomicrographs show the red
coloured attachment of style to stigma (left) and a more highly
magnified view of one of the rounded lobes (right).
that many pollen grains adhere to the surface of the stigma but
surprisingly, not to the horns. (This stigma appears to be
missing one of its projections.)
Still closer views show the
cellular structure in the red band between style and stigma.
On the left below can be seen
pollen grains clinging to this coloured band. The image on
right shows the short coloured ‘stripes’ that randomly cover the
With all but one of a flower’s
petals removed, the position of the ovary at the swollen end of
stigma/style is revealed.
Within the ovary, developing
green seeds are visible.
Higher magnification reveals
surface texture of a seed (left), and its attachment to the base
ovary by a thin, dark green strip (right).
leaves are so deeply lobed
that they are usually described as being fern-like. Young
are yellowish green in colour, while more mature ones are
Closer views of the back
a leaf show its simple vein structure, and speckled appearance.
A leaf’s upper surface shows
Veins not visible in the
macro-photographs become apparent in a photomicrograph of the
surface of a leaf. A higher magnification shows the
their associated guard cells that control gas movement into and
the leaf’s interior.
Notice in the images below
cells around the edge of a leaf are colourless, and that the
colour deepens quickly as we look towards its interior.
The cultivar ‘Burning Heart’
patented variety with asexual propagation prohibited. It
from mid-spring through to the first frost, and certainly
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
December 2012 edition of Micscape.
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