Close-up View of the Wildflower
by Brian Johnston (Canada)
The red clover plant is so common that I
suspect most people simply
accept its presence in the environment, and seldom take a second glance
at this small, but colourful wildflower. In fact, up - close, the
red clover is a thing of great beauty - not only for its striking
colouration, but for the uniqueness of its form. My hope is that
the images in this article provide the impetus for you to uproot a
plant and have a close look at one of our most ubiquitous wildflowers!
I am constantly on the lookout for
information about the wildflowers
that I macro-photograph. Occasionally, I find a particularly
obtuse description, that is “meaty” in the scientific sense, but
distinctly lacking in the transference of information to the
uninitiated. One of the “best” that I have found refers to the
blooms of the red clover.
mostly terminal, sessile, short-peduncled, usually closely
subtended by the stipules of the upper pair of leaves, dense,
subglobose to ovoid, 1.2–3 cm long; flowers sessile, 10–15 mm long,
rosy purple to creamy-white, erect; calyx-tube campanulate, narrower at
base, 10-nerved, pubescent including the inner margin of the
throat,.The teeth filiform from a triangular base, sparsely hirsute,
porrect, the upper about equaling the tube, the lower almost twice as
long; corolla about twice the length of the calyx….”
If the above is perfectly clear to
you, perhaps you might want to skip
to another Micscape article. This article is based more on the
concept of a “picture being worth a thousand words”.
Red clover belongs to the Fabaceae family, (previously called
Leguminoseae family), which has
many members, including the peas, beans
and peanuts. Family members have the ability to take nitrogen
from the atmosphere, and with the aid of soil bacteria, make it
available to other plants. The process is called “nitrogen
fixation” and is very important to the agricultural industry.
All red clover flowers have a
purple-pink colour, but there is
considerable variation in the intensity of this colouration. The
images below show a particularly colourful flowerhead. The bloom,
(about 2.5 cm in diameter), is composed of up to one hundred individual
flowers called florets.
The images show the main distinguishing
characteristic of the species - oval leaflets with a prominent white
“V” mark in the center. This marking is called a chevron.
Notice also that the stem and leaflets are intensely hairy.
The characteristic chevron markings
on the leaflets can be seen even
more clearly in the two images of red clover buds. It is unusual
to find a specimen as perfect as the one on the right. It is also
unusual (and supposedly lucky), to find four leaflets instead of the
normal three! (The genus name Trifolium
translates to “three
leaved”. The species name pratense
translates to “meadow”.)
As the flowerhead begins to bloom,
florets open in order from top to
The irregular edge of a leaflet’s
chevron is evident in the high
magnification photograph below.
Floret density in the flowerhead is
also variable. Some heads,
like the one on the left have florets spaced far enough apart, that the
underlying structures can be seen. Others, like that on the
right, are packed solid with florets. (Men often show the same
variation in scalp hair density. Unfortunately, my head now bears
a greater resemblance to the flowerhead on the left than to that on the
A closer look reveals the structure
of individual florets. The
upper-most petal has a noticeable vertical groove. This petal
forms the “banner” or “standard” of the flower.
banner are two lateral petals referred to as “wings”. It is these
wings that cause the flower’s structure to be called papilionaceous,
(like a butterfly). Finally, beneath the wings are two petals
joined to form the “keel”.
This keel encloses the reproductive
structures of the flower.
Immediately beneath the flowerhead,
there are usually three green
bracts (modified leaves) with
an intricate two-shaded green
pattern. These bracts abruptly taper to a slender tip. Many
hair-like green projections or rods, which themselves are covered with
finer hairs, can be seen growing up between the tubular bases of the
Viewed from beneath the flowerhead,
these bracts are very
attractive. Notice that all surfaces are covered with long fine
white hairs - particularly the stem. (The stem is more properly
called the peduncle.)
Occasionally, as in the bloom shown
below, the bracts are some distance
down the peduncle. This allows a clearer view of the hairy green
projections between florets.
The images below reveal the dark
red vertical stripes that decorate the
banner petal of each floret.
Higher magnification reveals a
common problem that occurs in the
macro-photography of small objects
like the florets of the red
clover. Even using the minimum
aperture of the Sony F-828 camera, (f 8), the depth of field is still
insufficient to keep all parts of the floret in focus
simultaneously. (The section of each floret that can be seen in
the photographs is about 4 mm long.)
If the two petals forming the
“keel” of the floret are removed, the
reproductive structures hidden beneath are revealed. Ten brown
anthers atop pale green filaments surround the single stigma, and the
style that supports it.
The anthers are the male pollen producing
organs, while the stigma is the female pollen accepting organ.
A closer view of an anther, using a
microscope, reveals its triangular
shape. Several pollen grains can be seen on its surface.
The stigma also has pollen grains
adhering to its surface.
A much higher magnification shows
that each grain is roughly
ellipsoidal in shape and has a longitudinal groove. The surface
is not smooth.
I mentioned earlier that the
intensity of colour varies in red clover
plants. Notice the paler shade in the bloom on the right.
Several additional images of this
lighter bloom follow. It is
interesting to note in the second image, that the florets have bloomed
from bottom to top. Many unopened florets are visible at the top
of the flowerhead (facing the observer).
Even higher magnifications reveal
the long tubular bases of the
florets. Notice that the stalks between florets are red-brown in
A much higher magnification of one
of the stalks shows it to be covered
with white hairs.
Other similar stalks in a different
flowerhead are green, and spotted
Finally, here are three additional
images of this extremely common
I can remember as a child, pulling
bunches of red clover florets from a
flowerhead, and sucking on the tubular ends to taste the sweet
nectar. Today, I am older and wiser. Examining flower parts
under the microscope has revealed the many animal denizens, invisible
to the naked eye, that inhabit flowers. The thought of swallowing
these creatures has taken all the fun out of such activities - a
perfect example of the innocence of youth!
The majority of the photographs in
the article were taken with an eight
megapixel Sony CyberShot DSC-F 828 equipped with achromatic close-up
lenses (Canon 250D, 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.) A few of the photographs were taken with an eight
megapixel Canon 20D DSLR equipped with a Canon EF 100 mm f 2.8 Macro
lens. 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.
- Dickinson, Timothy, et al.
2004. The ROM Field Guide to Wildflowers of Ontario. Royal
Ontario Museum & McClelland and Stewart Ltd, Toronto, Canada.
- Thieret, John W. et al.
National Audubon Society Field Guide to North American Wildflowers -
Eastern Region. 2002. Alfred A. Knopf, Inc. (Chanticleer Press,
Inc. New York)
- Kershaw, Linda. 2002. Ontario
Wildflowers. Lone Pine Publishing, Edmonton, Alberta,Canada.
- Royer, France and Dickinson,
Richard. 1999. Weeds of Canada. University of Alberta
Press and Lone Pine Publishing, Edmonton, Alberta, Canada.
- Crockett, Lawrence, J.
2003. A Field Guide to Weeds (Based on Wildly Successful
Plants, 1977) Sterling Publishing Company, Inc. New York,
- Mathews, Schuyler F.
2003. A Field Guide to Wildflowers (Adapted from Field Book
of American Wildflowers, 1902), Sterling Publishing Company, Inc.
New York, NY.
- Barker, Joan.
2004. The Encyclopedia of North American Wildflowers.
Parragon Publishing, Bath, UK.
Microscopy UK or their contributors.
Published in the June
2006 edition of Micscape.
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