A close-up view of fringed loosestrife.

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 ground!

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 “cones”.

Slightly later, the “cones” unfurl to reveal the shape of the flower’s petals.

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 supporting style.

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 glands.

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.

Photographic Equipment

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.

References

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)

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