Close up view of the wildflower corn speedwell
View of the Wildflower
by Brian Johnston (Canada)
Yellow and white wildflowers are
extremely common, and when one finds the much rarer, attractive
blue-violet blooms seen in the image above, it is worth taking a closer
look. This is particularly true since the plant doesn’t last very
long after flowering. In fact, it is one of the earliest bloomers
in the spring, and soon becomes obscured by the grasses and other weeds
that grow much taller. The plant photographed for this article
had already been partially hidden by long grass on a hillside, but a
hint of blue indicated its presence a moment before I would have
crushed it underfoot.
Veronica arvensis is an
annual, native to Europe, that normally grows in the form of a tangled
mat over the surface of the ground. If nearby plants compete with
it for sunlight, it grows upright stalks that can be up to 25 cm
high. (My plant was approximately 10 cm in height.) Near
the ground, the main stems branch into many side stems, however the
side stems themselves are mainly unbranched. Fine hairs cover
The common name “Speedwell” was chosen to reflect the speed with which
the plants spread. The species name arvensis is derived from the Latin
for “belonging to the plowed land”, and refers to its presence in lawns
As can be seen below, the plant’s flowers have four rounded petals,
with one being slightly smaller than the others. The flowers are
incredibly small – less than 5 mm in diameter! The corolla, a
structure formed by the petals, is a blue-violet colour which becomes
white at the “throat” where the petals are fused into a tubular
base. Darker, blue-violet lines radiate out from the flower’s
centre. They are thought to function as nectar guides to visiting
Closer views of a flower show its reproductive structures.
Emanating from the throat is a single pistil, and two stamens. In
most flowers, these structures have approximately the same length.
Notice the fragile style, and the much sturdier filaments.
Although the anthers, (male pollen producing organs), are actually blue
in colour, this is difficult to see because of their coating of white
Under the microscope however, the striking blue colour of the anther is
Higher magnification shows the ellipsoidal, or egg-shape, of each
Phase-contrast illumination, and a still higher magnification, reveal
that a grain has several longitudinal grooves on its surface.
The following two images show the surface structure of the stocky
filament that supports the anther.
A flower’s pistil consists of a thin white style and bulbous, white
stigma (female pollen accepting organ).
These two structures can be seen more clearly in the two
photomicrographs that follow. Notice the long, hair-like
protuberances that help collect, and retain pollen grains like the one
seen in the image on the right.
If a section of a Corn Speedwell petal is removed from the flower, and
examined under the microscope, its variable blue pigmentation, and
cellular structure are visible. Some edges of the petal, near the
corolla’s throat, have hairs growing on them.
At the very base of the corolla tube, the structure is green in colour
due to the presence of chlorophyll. Many hairs are also present
in this location.
Cool springtime temperatures can result in what are called
“infestations” of this tiny plant. In my opinion, a patch of Corn
Speedwell is better referred to as a visual “treasure”.
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. 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 photomicrographs were taken with a Leitz SM-Pol microscope (using
dark-ground and phase-contrast condensers), and the Coolpix
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.
- 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 April
2011 edition of Micscape.
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