A (second) close-up view of the teasel, Dipsacus fullonum
(Second) Close-up View of the
by Brian Johnston (Canada)
Spectacular because of its large,
unusual, egg-shaped flower-head, and its one to two metre height, the
teasel certainly stands out in the landscape.
Like other wildflowers, the plant
is known by many names. Dipsacus,
its genus name is derived from Greek, and means ‘to thirst’. This
refers to the fact that rainwater collects in a bowl-like structure at
the point where each basal leaf joins the main stem. For this
same reason, the Romans called the plant ‘Venus’s basin’, and the early
Christians in Ireland referred to it as ‘Mary’s basin’. Teasel’s
species name fullonum refers
to the occupation of a fuller, someone who used the dried flower-heads
to comb the tangles from wool. Thus ‘Brush and comb’, and
‘Fuller’s herb’ are other common names for teasel. Another name,
‘Johnny-prick-the-finger’ refers to the plant’s defensive array of
formidable prickles, or spines.
Teasels belong to the family Dipsacaceae. Although their
flowers appear similar to other composite flowers, there are technical
reasons for considering them separately. One of these is the fact
that in a composite flower, the edges of stamens are packed together
forming a cylinder around the style. In a teasel flower however, the
stamens are separate from one another.
The first image in the article
shows a typical flower-head in bloom. Notice the long, leaf-like
bracts that branch out from the base of the flower-head, and curve up
artistically around the bloom.
The following two images show a
flower-head in the ‘bud’ stage. The developing buds are well
protected by the tightly packed array of extremely stiff, sharply
pointed bracts that resemble bristles or spines. Notice that
these bracts are relatively short near the flower-head’s base, but
increase in length near its apex.
As is evident from the following
sequence of images, the flower-head begins to bloom in a ring around
its middle. Later, as we will see, the most central of these
flowers will die and two separate rings will continue to bloom, one
moving up towards the apex, and one moving towards the base.
Although individual flowers are difficult to see at this magnification,
their anthers, which extend out some distance from the flowers
themselves, are easily discernable. In total, there are
approximately 2000 flowers in each flower-head.
A closer view of the base of a
flower-head shows the top of the plant’s stem, and the ring of upward
Carrying a teasel plant home from
the ‘wild’ is not an easy task. Its stem is covered by extremely
tough, sharp spines. Even getting a grip on the plant in order to
cut through the stem is very difficult. (I usually hold the stem
with pliers while cutting it, and then transfer the stem to a cardboard
paper towel tube for the trip home.) Notice that the spines grow
along the light coloured ridges that run the length of the stem.
Between these ridges are pale green, spineless grooves.
The images that follow show the
rings of green bracts that grow from the top of the stem. Several
rings are visible, with the outer ones being longer than the inner
ones. The lower surfaces of these bracts are sparsely covered
Much closer views of a bract can be
seen below. Notice that individual spines are white in colour,
and thus they contrast with the green of the bract. Closer
examination reveals that the edges of a bract are white or light brown
Near the base of the flower-head,
the bristles are about the same length, or shorter than the
flowers. Although the bristles are green at their bases, they are
brown just beneath the tips, and white at their tips. The first
image shows anthers and filaments growing out from the flowers’ pale,
purple-tipped tubular corollas.
Near a flower-head’s apex, these
bristles are longer, and brown from base to tip. Notice the
orange globule of insect ‘spit’ adhering to the side of one of the
The three images that follow show
the pale green unopened flower buds, and their associated
bristles. The second image shows the long, transversely curved
shape of the bristles.
Views looking down onto the top of
a flower-head appear at right, and on the next pages. Notice that
the dome-like buds nearest the ring of blooming flowers have a deep
pink tint, while those farther away are less deeply tinted.
The images that follow show buds
that are about to bloom. In the first three, notice that the
light purple corollas of individual flowers are visible.
As was mentioned earlier, the
flowers in the central ring soon shrivel and fall from the
flower-head. This leaves many empty sockets which can be seen in
the image below. Upper and lower rings continue to bloom.
Four images follow that reveal the
top of the egg-shaped flower-head at this point in the blooming
process. Notice in the last image, how far each flower’s stamens
protrude beyond the corolla.
Macrophotographs showing the lower
section of the same flower-head reveal different bud tints that
indicate their order of opening.
As one moves up the magnification
scale, the flowers’ stamens, consisting of pale purple anthers and
colourless supporting filaments, become easier to resolve.
By choosing appropriate viewing
angles, and by using still higher magnifications, the structure of
individual teasel flowers can be seen. Each flower consists of a
tubular corolla 10 to 15 mm in length which is almost white near the
base, and pale to deep purple near its four-lobed end. Four
stamens protrude from each flower, and as can be seen in the third
image, so does a single white pistil.
Photomicrographs of the stigma, and
stocky supporting style can be seen on this page. Notice the
almost spherical pollen grains clinging to both stigma and style.
In the first two images, note how much greater the diameter of the
style is than that of a filament.
One lobe of the four-lobed corolla
is larger and longer than the others. The corolla tube does not
appear smooth at this magnification.
The reason for this rough
appearance can be seen in the four photomicrographs that follow.
These show the cellular structure of the corolla lobes. Notice
that some of the cells near the edge of the corolla lobes are much
larger, and have a rounded cylindrical shape (first two images).
Others on the surface of the lobes have a stubby hair-like appearance
(last two images).
As we get closer and closer to the
flower-head, the liberal coating of pollen grains on the surface of
anthers becomes visible. At the limit of the magnification
possible with my equipment, the spherical shape of the grains is
Under the microscope, the oval
shape and colouration of an anther can be discerned.
Still higher magnification shows
that pollen grains have a barrel shape rather than a perfectly
spherical one. As well, tiny protuberances are visible on a
Different illumination shows that
the upper surface of the anther is completely covered by pollen grains.
Extremely tiny, downward pointing
hairs cover the surface of a supporting filament in the high
magnification photomicrograph at right.
Beneath the flower-head, several
leaves can be seen growing from the stem. Notice that they are
stalkless and are arranged opposite one another. Each leaf tapers
towards its ends.
If the under-surface of a leaf is
examined using the microscope, the oval stomata and guard cells that
control gas entry into and out of the leaf are clearly visible.
Several bulbous glandular hairs can be seen growing from the colourless
While taking the previous
photomicrographs, I detected motion in the field of view. Closer
examination revealed numerous sucking insects on the leaf’s upper
surface. Notice the dark, almost black spots within each insect’s
The upper section of the teasel’s
stem is divided into two sections at the junction point of the
leaves. Notice the smaller diameter of the upper section, and its
darker colouration, with fewer ‘prickles’.
Beneath the junction point, the
colourless spines, and speckled brown longitudinal bands on the stem
Teasel is a biennial plant that
lives for two years. During the first year only a basel rosette
of ground hugging leaves reveals its presence. In the second
year, a long stalk is sent up which branches to hold numerous
egg-shaped flower-heads. During the autumn of the second year the
plant dies, and the stem, leaves, and flower-heads turn a brown
colour. Both the stalks and flower-heads persist through the
winter, often projecting up through the snow in a very attractive
display. The plants seen below were photographed in late August,
and had begun the transformation to brown.
Closer views reveal that the stems
retain their green colouration longer than the empty flower-heads.
In addition to being used
historically in the textile industry, dried teasel flower-heads were
utilized as bizarre ornaments in winter flower arrangements. In
New England they were even used by rural housewives to sprinkle water
on clothes before ironing!
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.
A 10 megapixel Canon 40D 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 (using a dark ground condenser), and
the Coolpix 4500.
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 July
2010 edition of Micscape.
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