Close-up View of
by Brian Johnston (Canada)
If the name “Loosestrife” brings to mind
the tall, purple-flowered stalks of the much despised “Purple
Loosestrife”, Lythrum salicaria,
you have a perfect right to be puzzled. For some strange reason,
the members of the Lysimachia
genus, and the Lythrum genus are referred to as
Loosestrifes! So much for scientific exactitude!
The Fringed Loosestrife plants photographed for this article were
growing within a couple of metres of a stream. Common habitats
for the plant are swamps, pond margins, wet thickets, and moist wooded
slopes. Notice that the common factor in each of these
environments is the presence of consistently moist soil.
Lysimachia ciliata is native across Canada and in some American States.
A view from directly above a plant can be seen in the first
image. It is this perspective that shows the distinguishing
characteristic of Lysimachia ciliata.
The blooming flowers all face the
This strange orientation can be seen in the image below that shows a
typical 30 centimetre high plant.
New buds are protected by five, sharply pointed, green sepals (modified
leaves). The bud shown has just begun to open, revealing the
bright yellow petals of the flower.
Strangely, the yellow petals are curled into pointed cone shapes at
this later stage in the opening process. Notice that the interior
base of a flower has a reddish colouration. The green pistil can
be seen at the flower’s centre, and radiating out from the pistil are
the five filaments. The anthers are hidden within the petal
Slightly later, the “cones” unfurl to reveal the shape of the flower’s
Most Fringed Loosestrife petals are fringed, (hence the common name),
or toothed near the tip, which is sharply pointed. Flowers are
from 2 to 2.5 centimetres in diameter.
As can be seen in the two images that follow, the plant’s flowers are
on long pedicels growing from the axils of the upper leaves. The
five, pointed sepals at the base of each flower are also visible.
(A pedicel is a small stalk bearing a
single flower. An axil is the joining point of leaf to stem.)
If a petal is examined under the microscope, the cellular structure of
the upper (epithelial) layer can be seen. The first
photomicrograph shows one of the many “imperfections” on the surface of
a typical petal.
Strange glandular protuberances like the one below, grow from the edges
of most petals.
By contrast, the edges of sepals have hair-like protuberances, some of
which have localized red pigmented cells.
The red pigmentation of the cells at a petal’s base can be seen in the
low magnification photomicrograph on the right below. Although
the petal’s surface appears to be covered with pollen grains, this is
unlikely. Fringed Loosestrife pollen grains are not spherical
(see later in the article), and the spheres in the image appear to be
connected to the petal by thread-like stalks. I have no idea what
these objects are!
Two views of the reproductive structures of the flower can be seen
below. Five long, brown anthers (male pollen producing
structures) are held aloft by pale green filaments. At the
flower’s centre, a single, relatively long pistil can be seen. It is
composed of a darker green stigma (pollen accepting organ) supported by
a lighter green style. The green bulge at the pistil’s base is
the flower’s ovary (seed producing organ).
Two views of an anther can be seen below. Several pollen grains
cling to the surface.
The convoluted upper surface of the stigma can be seen in the image on
the right below. Notice the glandular protuberances on the
These glandular structures can be seen more clearly in the higher
magnification photomicrographs below. The ones in the image on
the right appear to have “dried up”.
A much higher magnification view of the tops of the glandular
structures can be seen in the image that follows. Notice the
small size of the flower’s pollen grains compared to the spherical
Lysimachia ciliata pollen
grains are egg-shaped, but they appear to have dimpled grooves on their
surfaces. The more three-dimensional looking view on the left was
produced by having the phase-contrast condenser off-centre, and by
utilizing a non-phase objective to produce the image.
Although the plant’s lowermost leaves are oval, those at the level of
the flowers are lanceolate (lance-shaped). The clearly delineated
vein structure can be seen in the two images that follow.
Under the microscope, the leaf’s surface appears glabrous (hairless),
but its edge is ringed by short thick hair-like protuberances.
On the underside of a leaf, the oval stomata and guard cells, that
control gas transfer into and out of the leaf, are visible.
It is interesting to note that members of the Lysimachia genus are sterile to
their own pollen. This prevents self-pollination, which is
counter-productive to the long-term survival of the genus.
All of 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
dark ground and phase contrast condensers), and the Coolpix 4500.
Dickinson, Timothy, et al. 2004. The ROM Field Guide to Wildflowers of
Ontario. Royal Ontario Museum & McClelland and Stewart Ltd,
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)
Microscopy UK or their contributors.
Published in the
December 2007 edition of Micscape.
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