A Close-up View of the Wildflower
"Deptford Pink"

(Dianthus armeria)

by Brian Johnston   (Canada)

This small, but brightly coloured wildflower was given its name due to the fact that it was supposed to have grown in abundance during Tudor times in the fields near Deptford UK, now an industrial section of London.  Although the population of Deptford Pink plants is thought to be on the increase in Europe and North America, in the UK it is in serious decline.  In fact, the plant has an endangered listing, and is therefore protected in many areas.  I imagined that “Pink” referred to the colour, however some sources say that it relates to the serrated edge of each petal looking as though it was trimmed by “pinking shears”.  The genus name Dianthus comes from the Greek dios, meaning “of Zeus” and anthos, meaning “flower”, translating roughly to “flower of the god(s)”.  The species name armeria derives from the Latin flos armeriae, a type of flower.
The plants photographed for this article were growing in an open field near a row of trees.  The field was mowed infrequently, and the plants would appear a couple of weeks after each cutting.  This limited their height to about 15 centimetres.

Deptford Pink flowers grow in small clusters at the end of a thin stiff stem, which can be from 15 to 25 centimetres high.  Each approximately one centimetre diameter flower has five petals with toothed edges, and a sprinkling of small white spots.  The light green leaves are blade-shaped and often form V’s near the top of the plant.

Note in the two images that follow, the five lance-shaped (lanceolate) greenish-brown bracts, (modified leaves) immediately beneath the petals. These bracts tend to cover the tubular base of the flower and prevent the flower’s trumpet shape from being apparent.  In addition, most plants have three narrow green leaf-like bracts at the base of each flower.

A flower has five stamens, each consisting of a pale filament holding aloft a purple or red anther, (male pollen producing structure).  There are also two stigmas, (female pollen accepting structures), although they are out of focus in the images below, and are not visible.

Under the microscope a purple anther can be seen attached to its paler rod-like filament.  Several pollen grains are sticking to the surface of the anther.

A red anther is shown below.  The higher magnification image on the right shows many roughly spherical pollen grains.

Notice the single pollen grain at the centre of the image on the left below.  To the right is an enlargement of the grain revealing the faceted shape, and the circular depression on each face.

Each Deptford Pink flower has two stigmas which project out a considerable distance.  This I suppose increases the chance of fertilization by insect visitors.  Each stigma is hairy, and tends to be pink in colour at the tip.  Notice also that the upper bracts are striped in two shades of green, and are covered in fine hairs.

The following two images show the almost transparent glandular protrusions that encircle the stigma.  These hairs ensure that any pollen grains brought by visiting insects are retained by the stigma when the insect leaves.

Some of the surface detail on a pollen grain adhering to the stigma is visible in the image below.

The following photomicrograph illustrates the adherence of pollen grains to the glandular stigma hairs.

While examining a flower petal under the microscope, I was surprised to find that at the centre of each white spot on the petal’s surface, there is a single tiny hair growing perpendicular to the surface.  (What, I wonder is the purpose of these hairs?)

Before blooming, a Deptford Pink plant has very grass-like leaves.  This makes identification very difficult until the plant blooms, revealing the characteristic flowers.  As the photograph shows, all surfaces are covered with fine downy hairs.  The higher magnification image on the right shows a very immature bud, tinged with red.

The fine hairs at the edge of a leaf are visible in the photomicrograph below.  On the right is an image of a hair like structure which was growing from the base of one of the bracts.

Although this diminutive member of the pink family can’t compete with its more spectacular close relative the carnation, it nevertheless deserves close study when one is lucky enough to find a specimen.

Photographic Equipment

The photographs in the article were taken with an eight megapixel Sony CyberShot DSC-F 828 equipped with achromatic close-up lenses (Nikon 5T, 6T, Sony VCL-M3358, and shorter focal length achromat) used singly or in combination. The lenses screw into the 58 mm filter threads of the camera lens.  (These produce a magnification of from 0.5X to 10X for a 4x6 inch image.)  Still higher magnifications were obtained by using a macro coupler (which has two male threads) to attach a reversed 50 mm focal length f 1.4 Olympus SLR lens to the F 828.  (The magnification here is about 14X for a 4x6 inch image.) The photomicrographs were taken with a Leitz SM-Pol microscope (using a dark ground condenser), and the Coolpix 4500.  


The following references have been found to be valuable in the identification of wildflowers, and they are also a good source of information about them.

A Flower Garden of Macroscopic Delights

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.

 All comments to the author Brian Johnston are welcomed.

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