Late summer orchids of Rondeau, all are species at risk!

 There are several highlights for botanizing later in the summer. Certainly the main highlight for me is to check on three orchid species that are found at Rondeau, all of which are quite rare in Ontario. One is so rare that its only Canadian location is at Rondeau. Another one is quite restricted, but so very small that the average person would not even see it. The third, and latest flowering one, is rare, but relatively widespread in the park and generally more visible.

 Keen botanists will likely already know the three I am talking about. The first, and rarest one, is the Nodding Pogonia (Triphora trianthophoros). 

Its peak time of flowering is typically the third week of August, although on rare occasions I have seen one or more in flower on even the last day of July. This year I went out into one of its best known locations on August 1, just to see what was happening, and was quite surprised to see several in flower. One even had a double flower!

The tricky thing with this orchid is its flowering strategy. All the buds develop to a certain stage, and then remain as is. It takes a fairly significant drop in the overnight temperature to trigger the buds to open on the morning of the second day following this temperature drop. All the buds that are ready will open, but just for a single day, and it may be a week before the next suitable temperature drop triggers the next set of buds to open.

The weather this August was anything but suitable for this flowering strategy. An overnight temperature would seem suitable, but then the next three nights would see the temperature drop even more! I think the plants were a little confused with this abnormal sequence, and as a result, their flowering was difficult to predict. On more than one occasion I went out expecting, or at least hoping, to see some in flower, but in some cases they flowered the day before and were not worth bothering to photograph. And the next set of buds were not well developed at all. This next photo shows what a single plant looks like, from a distance of about 6", with a 100m macro lens! They can be easily missed, even when one knows exactly what to look for, so I seldom go out unless I am quite sure they will be in flower, and if it is the wrong day, I don't spend much time looking so as to not accidentally step on them.

I do know where some are likely to be found, even if not flowering, and by being extra careful, I managed to find some that were tucked beside a fallen log, and almost impossible to see. This next photo is of a pair of even tinier plants with very undeveloped flower buds, and again, photographed with a 100mm macro lens from a close distance. The plants are merely 4-5 cm high. Even at that, I greatly cropped the photo to get this.

Overall it was one of the poorest years I can remember in my 50+ years of monitoring this endangered orchid. Probably the relatively dry weather at a critical time was partly the cause. However I did manage to get a few photos. These next two were taken in the 3rd week of August window. All were almost pure white, and while I always hope for some with a magenta tinge that I find even more attractive, the second photo is the only one that had even a very slight magenta tinge. Ones with a magenta tinge usually occur towards the end of the flowering season. Oh well, maybe next year.

 After blooming, the seed pods develop, as this next photo shows. Upon ripening, the seed pods will become erect, and start to dry, with the sides of the pod starting to split open so that a slight gust of wind will cause the seeds inside to disperse.

The second orchid I referred to, is about the same size as the previous one, and at least once the flowers open up, will remain open for several days. However for the more common variety of this one, Autumn Coralroot (Corallorhiza odontorhiza) which is also rare, the flowers don't open, but are self-pollinated! The rarer variety, known as Pringle's Coralroot and shown here, has flowers that do open. This first photo shows a group of four plants.

A closer look at the arrangement of flowers.

Closer....

And finally, a 'head-on' view of the lip of a single flower, which is probably only about 4 mm wide.

Not exactly a show piece for the horticultural industry, but an interesting orchid nonetheless, and it is native!

The third, and last orchid to be found flowering at Rondeau is the more common of these three. It is known as Great Plain's Ladies' Tresses (Spiranthes magnicamporum).

I found my first one with a few of the lower flowers starting to open up on September 13.

A couple of days later, there were a few more starting to open.

It is rare that all of the flowers are open at the same time, but sometimes most are. There are other species in the Spiranthes genus that look similar. A couple of the key characteristics of this one is that when in flower, it has a 'fragrance' that I think is similar to hot plastic. But without getting close enough to smell it, a close look shows a slightly yellow/tan colour well inside an open flower. None of the other Spiranthes have this coloration.

There is some slight hairiness to the outer white parts of the flower, and the sepals flare slightly back if viewed from the side.

 That's about it for Rondeau's orchids for this year. But by next May, another one of the 19 species of orchids will appear. Can't wait!

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