A Close-up View of the


Pulsatilla vulgaris  'Rubra'

by Brian Johnston   (Canada)

The pasque-flower belongs to the Buttercup family (Ranunculaceae), and is closely related to the genus Anemone.  For this reason, one of the alternative names for the plant is “meadow anemone”.   It is native to the short turf, and alpine meadows of North America, Europe, and Asia.  The Pulsatilla vulgaris species is native to Great Britain, but it is now very scarce in the wild.  Pasque-flowers’ finely dissected leaves, colourful blooms, and silky coating of fine hairs, make it a popular garden plant.

The genus name Pulsatilla is derived from the Latin pulso which means to strike, or set in violent motion.  Why this name was chosen is not entirely certain, although it may refer to the fact that all parts of the plant are poisonous and may cause stomach distress if ingested.  Vulgaris, the species name, translates to common.  The common name pasque-flower was given to the plant, due to the fact that it flowers around Easter time.  In Hebrew, the term for passover is pasakh, hence pasque.

This article focusses on the red variety of Pulsatilla called ‘Rubra’.  Other available colours are purple-violet, and white.  Cultivars have been produced with mixed colours, and even semi-double flowers.

The image above shows the main characteristics of a pasque-flower bloom.  It has six velvety petals with curled, pointed tips, surrounding a ring of bright yellow stamens, and a mass of pink-tipped pistils.  All plant surfaces are covered in fine, soft hairs as can be seen in the images below.  Note in the right-hand image, the location of the bracts (modified leaves).  In many flowers, these are positioned right beneath the bloom, but here they are considerably lower - midway between bloom and leaves.

A partially opened flower can be seen in the images below.  The most striking characteristic (other than the intensity of the bloom’s red colour), is the length and density of the downy hairs on the surfaces of the plant.

The top surfaces of petals feel velvety to the touch, but there are no significant hairs present.

Two photomicrographs show a petal’s upper surface at low (left), and high (right) magnification.  The hairs seen in the left image are extending into the view from beneath the petal.  The image at right shows the roughly spherical shape of the petal’s cells.  (The colour difference in the right image is due to the fact that Photoshop’s ‘auto-levels’ function was used to increase contrast.)

In contrast to the upper surface, a petal’s lower surface is extremely hirsute! 

Note the darker red spots, and three-dimensional radial veining, visible on the petal shown below.  The photomicrograph at right shows some of the hairs growing from the petal’s surface.

Three views of a fully open pasque-flower bloom follow.

If a flower’s petals are removed, the mass of reproductive structures is easier to see.  Multiple rings of stamens, consisting of yellow anthers (male pollen producing organs) supported by paler yellow filaments, grow from the flower’s base.  At the centre of the group of stamens is a column formed by many styles, topped by light pink stigmas (female pollen accepting organs).

An immature anther can be seen below.  The first image shows the overall bi-lobed structure.  The second reveals the point of connection of filament to anther, and the last image shows the hairs that grow from the surface of the filament.

A mature anther has a less smooth, more bumpy surface, with occasional adhering pollen grains.

Another example follows.

The two images below show the column formed by the many stigmas (pink), and their supporting styles (yellow-green).  The tip of each stigma stands out, as it seems to be semi-transparent.

One-half of a flower’s stamens were removed to obtain the view shown below.  Notice how the pistils spiral, from stigma tip to style base.  The bottom ends of the styles are hidden in a dense mass of long white hairs.

Two views of a stigma tip, from different angles, can be seen below.  Notice that the top-most cells are spherical, whereas lower ones are tubular in shape.

Along their length, the styles are covered in tiny hairs.

Stamens and pistils are joined at their bases to the bulbous structure shown below.  This is the ovary (seed producing organ).  The image at right shows the flower’s hairy stalk.

Although the top surface of a leaf has few hairs, tufts of long white hairs grow from the tips of each of the leaf’s lobes.

The under-surfaces of leaves have many long hairs, as can be seen in the photomicrograph below.

Also present are many oval stoma, and associated guard-cells, that control gas entry into the internal structure of the leaf.

The pasque-flower is not native to the area in which I live, but it is readily available in garden-centres in springtime, for planting in the garden.  Although its flowers are small, about five centimetres in diameter, their deep colour, and the plant’s downy surfaces, make it an attractive addition to the flower-bed.

Photographic Equipment

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 several images.

The photomicrographs were taken with a Leitz SM-Pol microscope (using a dark ground condenser), and the Coolpix 4500.

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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