Close-up view of the wildflower heal-all, Prunella vulgaris

This extremely common plant is found worldwide, and may grow as tall as 40 cm in the “wild”, or as short as 2 cm in locations such as your lawn, where it is frequently cut or mowed. Its common names, Heal-All, Self-Heal, and Cure-All are a reference to its use in “herbal medicine”. Wouldn’t it be wonderful if the appellations were actually correct! (I suspect that the “-All” part might be a slight exaggeration!)

Prunella vulgaris is a member of the mint family (Lamiaceae). Some botanists refer to two varieties of the species, the European one being called vulgaris, and the North American one being referred to as lanceolata. Both species grow in most locations, and since they are almost indistinguishable, the particular species name is not overly important for this discussion.

The image above shows a Heal-All flowerhead in full bloom. The many shades of purple, violet, and green make this a very attractive, (but small), wildflower.

Two images of the bud-stage of the flowerhead, (inflorescence), can be seen below. The structure is composed of parts that are so tightly packed, that they are difficult to distinguish. Keep in mind that the inflorescence of Prunella vulgaris is described as a verticillaster. The flowers are borne in rings, (or whorls), of decreasing diameter at intervals up the stem. As the tip of the stem continues to grow, additional whorls are added. This type of inflorescence is common in members of the mint family. In the images, there are green leaflets indicating each new level, and reddish-purple sepals (modified leaves) that are flattened into an envelope, from which the buds and flowers will emerge.

When a flower blooms, its pale purple petals emerge from the sepal envelope.

Notice that the top of the verticillaster is flattened. In most flowerheads, the blooms are arranged vertically in rows, at right-angles to one another.

Other Prunella vulgaris plants, like the one shown in the images that follow, look quite different. This is an example taken from a lawn which is cut frequently. The purple colouration of the bracts doesn’t have enough time to intensify, and so the flowerhead appears much greener than the earlier one. Also notice that the flowers are not arranged in the perfect four-fold symmetry of the earlier one.

Heal-All flowers have two petal-lobes, forming an upper lip that is hooded, arching out over the stamens, and a lower lip which is less intensely coloured. Notice that the sepal pockets have a sharply pointed fringe. The green leaflets are also fringed, but this time with long white hairs.

A front and side view of a blooming flower can be seen below. Beneath the upper and lower lips, the flower’s petals are fused to form the corolla tube.

Under the upper, hood-like lip are the flower’s four stamens, arranged in two pairs – an upper and lower. The flower’s pistil grows between the two upper stamens, but it is difficult to see in this image.

In the closer view at left, below, one of the stigma’s two lobes can just be seen beneath the hood, projecting down like a fang. In the view on the right, the entire stigma is visible, with both its lobes, in the middle of the group of anthers.

Speaking of anthers (male pollen producing structures), here is a photomicrograph showing one. A multitude of white pollen grains sit on the top surface, which is purple in colour. Between the white base and the purple top, is a light blue band. The forked filament that supports the anther is also present in the image.

Closer views of Heal-All’s pollen grains can be seen below. Each is ellipsoidal in shape, and has a noticeable longitudinal groove on its surface.

Here is a much better view of the forked stigma, (female pollen accepting organ), positioned between the upper two anthers.

Under the microscope, each lobe has adhering pollen grains.

Higher magnification views of a stigma lobe follow. In the first image, you can see that part of the lobe’s surface is covered by thick, hair-like protuberances.

Segmented hairs growing from the top surface of the flower’s upper petal are shown below.

Once a flower has bloomed, the wind, or some other disturbance, causes it to fall out of the sepal pocket. The pocket then looks like a bulged open envelope. Examples of these flowerless envelopes can be seen below. (Purple-fringed sepals, like those shown below, tend to occur more in “wild”, rather than “lawn” plants.)

For comparison, here is an example showing a lawn flowerhead that has completely finished blooming.

The plant’s leaves are lance-shaped (lanceolate), and are positioned opposite one another.

Upper and lower views of a leaf’s surface are shown below. Notice the extremely tiny hairs that grow on the leaf’s edge, and on the prominent vein on its underside.

In my area, Heal-All plants begin to bloom in early May, and continue until the end of September. They are truly ubiquitous – I have found them in the most unlikely places! Unfortunately, many are so small, that a passerby might miss them. The next time you go for a walk, look for them. They are worth a close-up view!

Photographic Equipment

Approximately half of the photographs in the article were taken with an eight megapixel Canon 20D DSLR and Canon EF 100 mm f 2.8 Macro lens. An eight megapixel Sony CyberShot DSC-F 828 equipped with achromatic close-up lenses (Canon 250D, Nikon 6T, and Sony VCL-M3358 used singly, or in combination), was used to take the remainder of the images.

The photomicrographs were taken with a Leitz SM-Pol microscope (using a dark ground condenser), and the Coolpix 4500.

References

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, NY.

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.

A Flower Garden of Macroscopic Delights

A complete graphical index of all of my flower articles can be found here.

The Colourful World of Chemical Crystals

A complete graphical index of all of my crystal articles can be found here.

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