Late summer orchids

 This post has been in the works for a few weeks, since there have been a few orchid species typical of the late summer, and several are rather rare. Currently there are 19 species of orchids known from Rondeau, 18 if which are native. I have seen all but one species, so far. Of course one of the highlight orchids is that endangered species, Nodding Pogonia a.k.a. Three-Bird's Orchid, which is currently only known in Canada at Rondeau.

It used to be known from a private woodlot in eastern Essex County, but hasn't been seen there for several decades. Forest changes and activities in the forest have undoubtedly resulted in its demise there, but it is still possible. Access to privately owned properties have become increasingly challenging, since the presence of an endangered species might result in restrictions to what the landowner has planned for their property.

Regardless, this species has been known from Rondeau since about the mid 1960s, and their are several locations in the park. Fortunately for the species, these locations are mostly away from existing trails and roadways, although on rare occasion one or more can pop up within view of a trail. I have been following/surveying this orchid since 1973, when I encountered it during my first year of working on the naturalist staff of Rondeau.

It may begin flowering in very late July and even flower into the middle of September, but its peak flowering time is about the third week in August. What makes this orchid so intriguing is that it is very small, and flowering is very weather dependent. All of the potential buds develop to a certain stage, and then stop. It is only after a significant drop in the overnight temperature, that all of those buds at this stage will open. And then they will only remain open for a day, and it may be a week or so before the next set of buds will open, depending on the temperature triggers.

This is what a developing orchid looks like before flowering. You can see by its size relative to last year's fallen leaves it is emerging through, it is anything but showy.

 Its scientific name, Triphora trianthophoros, as well as the Three-Bird's Orchid name, is based on the fact that usually a plant will produce three buds, and on rare occasions, all three will open on the same day! This next photo shows a single plant, with all three flowers open at once. I don't see this every year, but this photo was taken in 2024.

 

 This photo of the three flowers is located in the extreme upper left of this next photo.

I was quite pleased to come across this concentration of the orchid. Normally they will occur in small groups of three or four, or sometimes just be singles scattered on the forest floor. This was one of the largest concentrations I have seen in recent years. They are so photogenic, I have many dozens of photos from over the years. Certainly a macro lens and flash is required for the best photos.

Sometimes one gets a bit of a surprise along with the photo. This next photo is an example. At first I thought it was just another, typical flower.....

...but when I got a closer look at it on the computer, I noticed something peeking out.

I am not sure exactly what it is, but it is possibly a pollinator. When I was studying this orchid in the 1980s in preparation for writing the official status report, I collected some pollinator insects found on the plants, and it turned out they were mostly of the Halictid group which are types of sweat bees. This individual isn't fully shown, so it is not conclusive, but it has a strong resemblance to members of that group of insects.

A full frontal look at a plant with a single flower, may show the single, small roundish leaf, as in the following photo.

I particularly like the ones that have a tinge of magenta in the flower. Some are almost pure white, but it seems that later flowering ones are more likely to have the magenta tinge. I don't know what causes this, and some years they are almost all white ones.

Moving on to other late summer orchids, I have seen this next one called the Sphinx Ladies'-tresses.

Fairly similar, but flowering a bit later, usually about the middle of September, is this next one, which is called Great Plains Ladies'-tresses. It is a bit larger than the Sphinx and has a slightly yellowish tinge to it, especially when you look down the 'throat' of the flower. It also has a more fragrant scent to it.

The last orchid to flower at Rondeau is this next one, the Autumn Coralroot. And yes, this photo shows it in flower! There are two varieties of this orchid, and one will look like this, with a very small flower that hardly opens and droops downward, but the seed capsule forms anyway. This orchid is fairly rare throughout its range, and although I didn't look intensively for it this year, I only came across this single plant. However being as small as it is, and it isn't exactly showy, it likely occurs in places scattered throughout the pine-oak forest of Rondeau.

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