Close-up View of the
by Brian Johnston (Canada)
The attractive blooms of this plant are
supported by 30 to 40 centimetre long, delicate stems. As a
macro-photographer, I dislike such stems intensely! Even indoors,
the slightest air movement causes the flower being photographed to
‘bob’ up and down, left and right, and even backwards and forwards
uncontrollably. What causes the air to move? Breathing, and
focusing the lens are the worst offenders. When I think of
the pincushion flower, it is the periods of breath-holding that come to
mind most readily. Unfortunately, long distance underwater
swimming is not one of my interests, although I have certainly had
enough training during the photography of this plant!
Pincushion flower’s common name
derives from the fact that its long, needle-like pistils resemble pins
sticking into a pincushion. The plant studied here is a member of
the teasel family (Dipsacaceae).
Some of its members belong to the genus Scabiosa, the
name of which was chosen because the plants were believed to cure
scabies. (Other sources refer to the name being derived from the
Latin scabiosa, which
translates to “rough”.) The species name columbaria means
columbaria is native to the Mediterranean region of Europe,
Western Asia and North Africa. Alternative common names are
Pigeon scabious, Small scabious and Dove pincushion. Forty years
ago, a grower for the Farplants organization, David Tristam, found an
exceptional example in a garden in Ireland. Cuttings from the
plant were grown by Tristam for many years, and the cultivar was
finally marketed as ‘Butterfly Blue’ in the late 1990’s. The
Perennial Plant Association awarded the title ‘Perennial Plant of the
Year 2000’ to Scabiosa columbaria
Notice in the images that follow,
that the stalk of one of the plant’s bud-stage flowerheads has grown
longer, and that the sepals (modified leaves) have begun to open out
into their final horizontal positions.
Long before the flower blooms, the
stem has lengthened sufficiently to allow the flowerhead to
actively “search for light”.
An immature flowerhead is ringed by
hairy, green, pointed sepals, and is composed of a number of light
coloured flower buds with many bright red, hair-like threads sticking
up between them.
The three images below show a
botanical abnormality – conjoined stems, and conjoined immature
flowerheads. The stems are downy-soft due to their being covered
with fine white hairs.
Side and back views of a ‘normal’
bud-stage flowerhead follow.
At higher magnifications, it can be
seen that the surfaces of unopened, individual buds, are also covered
with fine white hairs. Each red projection is a pappus.
(Pappus hairs are attached to the seed of a plant, and may aid in its
transfer to another location.)
As time passes, changes begin to
occur in the flowerhead. One change has to do with the shape of
the unopened buds. Those near the edge of the flowerhead become
oval rather than circular, and they increase in size compared to those
at the centre. In addition, all of the unopened buds take on a
This colouration can be seen
clearly in the two images below, showing outer, and inner portions of a
Finally, the buds begin to
bloom. Central ones open before those around the perimeter.
Shortly thereafter, the central
flowers have opened sufficiently to allow the flat-topped, beige
stigmas to be seen. Notice that the petals have parallel sides
(rather unusual), and a rounded tip.
Within a day, the flowerhead is
completely in bloom. I find it strange that the marketers of this
cultivar would choose to name it ‘Butterfly Blue’. To my eyes,
all of the plant’s blooms are more purple than blue! Perhaps
‘Butterfly Lilac Blue’ would be a better description.
The two images below show the ring
of pointed sepals, of varying length, that cup the bottom of the
Higher magnifications reveal their
The flowerhead is composed of
large-petaled ray flowers in an outer ring, and a central disk,
containing much smaller-petaled disk flowers. Ray flower petals
are much deeper in colour than those of disk flowers.
As you can see below, a visiting
insect would have a difficult time landing on the flowerhead’s central
disk, without coming into contact with several pistils, (beige stigmas
held aloft by purple styles).
On the other hand, the relatively
uncluttered surfaces of the outer ray petals might provide better, but
less efficacious landing spots.
The image on the right below shows
a low magnification photomicrograph of a petal. Notice its
At the top edge of a petal, tiny
cylindrical cells can be seen against the black background.
The shape of these cells can be
seen more clearly in the two images that follow, showing the central
area of a petal. Note that the strange colouration is produced as
a side-effect of using Adobe Photoshop’s
‘Auto Levels’ function to
If all of the flowers are removed
from one-half of a flowerhead, its structure becomes evident. In
the left image you can see individual tubular disk flowers, with their
petals fused together at the bottom. The image on the right shows
the increase in size of these flowers as one moves towards the outer
edge of the flowerhead. The outermost ring consists of flowers
that have larger, and more deeply coloured petals.
Earlier in the article I mentioned
the numerous red hairs, (pappi), that grow out from between the
flowers. In the mature flowerhead, their short length prevents
them from being visible to an ‘outside’ observer.
Although no mention has been made
of a flower’s male reproductive organs, they do exist! Stamens
are hidden deep within the flower’s fused petal tube, and are therefore
difficult to see. Pollen covered anthers, (male pollen producing
structures), are visible below in an outer ray flower (left image), and
in a central disk flower (right image).
The shape of an anther can be seen
in the photomicrographs that follow. The one at right shows the
anther’s supporting filament.
Several of the fine hairs that
cover the outer surface of a disk flower petal can be seen in the
higher magnification photomicrograph below.
A single disk flower is shown
below, with its pistil protruding almost twice the length of the petal
tube. The photomicrograph at right shows its white stigma, and
purple, supporting style.
Higher magnification reveals that
the surface of the stigma is covered with circular, stubby
The long cells that make up the
surface structure of the style can be seen below.
columbaria has leaves of variable shape. The one seen at
left is lance-shaped, and finely divided into lobes of differing size
and shape. The leaf seen on the right has a typical ‘lance’
shape. The upper surfaces of both are covered in fine hairs, with
those at the edge being longer, and having a larger diameter.
On the left below, is a
photomicrograph showing the cellular structure of the upper surface of
a leaf. The image at right shows a higher magnification
photomicrograph of the hairs growing from a prominent vein on the
leaf’s lower surface.
At first glance, the flowerheads of
Scabiosa columbaria look as
though they might belong to the aster family, (rather than the teasel
family), because of their similar ray and disk flowers.
Irrespective of their family origins, they are certainly unique, and
All of the macro-photographs were
taken with an eight megapixel Canon 20D DSLR equipped with a Canon EF
100 mm f 2.8 Macro lens which focuses to 1:1. A Canon 250D
achromatic close-up lens was used to obtain higher magnifications in
The photomicrographs were taken
with a Leitz SM-Pol microscope (using 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 Chemical Crystals
A complete graphical index of all of my crystal articles can be found here.
Microscopy UK or their contributors.
Published in the
September 2008 edition of Micscape.
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