Great Egret

Great Egret

Sunday, 26 July 2015

Some late season orchids of southern Ontario

The subject of orchids is of interest to a great many people. The average person would not be aware of the fact that there are approximately 60 species of orchids growing wild in Ontario, and 18 of them are found at Rondeau Provincial Park. There are actually 19 species that have been recorded for Rondeau, although one, the Helleborine (Epipactis helleborine) is not native.

I wrote about early season orchids quite some time ago, and you can find that post here. This post will carry on with the orchid theme, but focus on species one might find in the later part of the season.

One of the orchids currently in flower at Rondeau is Small Green Wood Orchid (Platanthera clavellata).

 These photos were actually taken a couple of years ago. In checking some of the plants yesterday, I only noted a couple of individual flowers actually open, but in the next few days they should all open up. As one can see from the photos, this orchid isn't spectacularly coloured, and can easily be missed unless an observer knows what to look for. Case in point: they are growing on this rotting log in the slough, which is covered with lots of other vegetation!
The sloughs are, comparatively speaking, full of water this year, making access to such fallen rotting logs difficult. On occasion, one can find them growing in the mucky soil at the edge of the slough.

An orchid that may still be in flower, but does not occur at Rondeau is White Fringed-Orchid (Platanthera blephariglottis). It has been recorded in wet prairie north of here, as well as in fens and bogs. I photographed this orchid in a beautiful bog in Huron County a few years ago.

Somewhat similar in structure but very different in appearance to White Fringed-Orchid is this next one, the Yellow Fringed-Orchid, although it is more orange than yellow.

Sadly this one is likely extirpated (gone) from Ontario. If it were still present, it would likely be in flower in late July to early August. There were historical records from savanna habitat in the Leamington area prior to 1901. And no, I am not old enough to have seen this there, nor did I discover a time machine.....I visited a very nice prairie/savanna area in the greater Toledo, OH area with two other orchid hunter/photographer types in the late 1980s where some of these fabulous plants still occur. The photos here are scanned from my slides taken during that memorable foray.

An attempt was made to grow some plants from seed in the mid-1990s and plant the young plants in promising habitat in the Ojibway Prairie area, where other historical records indicated they once occurred. Follow-up searches to date have not indicated that the plantings were successful, but it takes a few years for plants to mature and flower and it has been ten years or more since anyone last investigated.

One of the rarest orchids in Canada is one that will be flowering as soon as early August: Nodding Pogonia (Triphora trianthophora). It does occur at Rondeau, and is currently the only known location for it in the entire country.

I wrote extensively about this endangered orchid in a previous post, which you can see here.

Towards the middle of August, one of the several species of Ladies'-tresses orchids will appear. A rare one, which does not occur at Rondeau but on rare prairies elsewhere, is the Southern Slender Ladies'-tresses (Spiranthes lacera var gracilis). Note the spiralling arrangement of flowers, each of which as a distinctive green centre.

In very early September, one may be able to find one of the smallest of our native orchids, the Autumn Coralroot (Corallorhiza odontorhiza). It has a flowering and a non-flowering form, yet both appear to produce seed. It is about the size and diameter of a pencil, but with its brownish-purple stem and diminutive or non-existent flowers, is very difficult to find even when you know where it is. This next photo shows it in all of its non-flowering glory, greatly magnified!

Another Spiranthes is the Yellow Ladies'-tresses (Spiranthes ochroleuca). One of the sites in Chatham-Kent seems to have been destroyed, but another small population on private property is still around. I photographed this in September of 2014, although it is a little past its best. It has a creamy yellow centre of its flower.
The largest Spiranthes in our area is Great Plain's Ladies'-tresses (Spiranthes magnicamporum), appearing at Rondeau in good numbers by mid-September and lasting until about the first of October. Its flowers are relatively massive compared to the others in that genus, and it has a distinct scent. Some say it smells a bit like vanilla, but not to me. I think it smells faintly like a soft plastic toy that has been left in the hot sun for too long! Not sure what that says about my olfactory.......

The smallest Spiranthes that grows in Ontario, but has yet to be found at Rondeau, is Oval Ladies'-tresses (Spiranthes ovalis). One can tell from this next photo, where it is on the left and S. magnicamporum is on the right, just how small it is.

It is also the latest flowering orchid we have, often not beginning to flower until about the end of September and continuing well October. I even found one still flowering on November 11 one year. It was first found at Walpole Island in the early 1980s, but seems to have disappeared from there. However it is known from several locations on Pelee Island.

Oval Ladies'-tresses

So there is a bit of information on some of the orchids present in southern Ontario in the latter part of the season!


  1. A fantastic botanical blog posting! It amazes me how frail these plants are. Its too bad they couldn't be transplanted or boosted with seedlings. A great mix of information that is complimented with great photography... As always!

    1. Thanks, Dwayne....this group of plants always creates interest. Some orchids transplant easily, but most do not due to the mycorhizzal association they have with other elements of the soil.

  2. I remember your last orchid blog. They are what I call 'entertaining' flowers because of the many faces they present.
    love and blessings, Paula.

    1. Hi Paula.....orchids are entertaining in so many ways. I still have the photos of some that you sent awhile back.