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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Birds, orchids and a bit of catching up

 Birds continue to be one of my things of focus when I am out of doors, of course. An outing yesterday to Rondeau resulted in seeing a good variety, especially of warblers and other small passeriformes, but they were hard to get photos of as they darted in and out of berry bushes that lined the trails and roads. I also scanned the lake, hoping that my first of season Red-throated Loon might be in sight, but it was not to be. I did see about a dozen Common Loons, however, and relatively close.

There likely were more, as they spent a lot of time diving under, and so it was hard to tell exact numbers. I'm sure a scope and more time would have revealed quite a few more. They will be increasing in numbers as they move southwards from their northern lakes.

The only warbler that I got on camera was one of the dozens and dozens of Yellow-rumped Warblers, which greatly outnumbered all other species.

I did take a bit of time to photograph a few tree species that I hadn't bothered much with in the past. Some are native such as Green Ash

Many fruit

This species shows moderately long leaf petioles, not as long as those on White Ash, but certainly a lot longer as those on Black Ash.

Eastern Cottonwood

Swamp White Oak, from a few years ago

....and White Ash, which has much longer leaf petioles. All native ash species are considered to be at risk, since the Emerald Ash Borer (EAB) that arrived a couple of decades ago has killed off many. Fortunately even relatively young individuals produce seeds, so that there is a lot of regeneration going on, and maybe eventually the species will once again dominate native forests. They may not reach the longevity and large sizes of before the EAB days. Time will tell.

under side

upper side

And some that I photographed are not native, but fairly abundant, such as Black Locust. The first photo shows the typical leaf arrangement, with the leaves showing signs of a mining insect.

This next photo shows the typical double thorn at the base of some of the leaves on a main stem.

Northern Catalpa, shown next, is also a non-native species. It had been planted by various cottagers many years ago, and some of the fruits, and therefore new individuals, are showing up in places between Lakeshore Road and Harrison Trail.

Another non-native species, and the origin in the park is unclear, is White Popular, which can grow in large clones, especially in the sandy openings along the lake shore. The leaves are distinctive with their white edges, and quite whitish undersides.

On one occasion I took a quick look at a fallen branch along the trail, and noted this nest. It is likely a vireo nest, and given the location in the main part of the beech-maple forest, is a Red-eyed Vireo nest. This vireo species is by far the most abundant of the vireos at Rondeau,

I also saw this Northern Watersnake out for a stroll along Harrison Trail. It is quite a ways from what I would consider its normal habitat, but there it was.

One of the things I hadn't really discussed much in blog posts of a few weeks ago, is the current status of one of Canada's rarest orchids, the Nodding Pogonia. It wasn't a great year for them, although I did see several dozen in the general vicinity of the main patch. It was quite a few less than the sometimes several hundred I see here.

Most were singles, and were predominantly white. I always look forward to seeing the more magenta colour forms, but it didn't happen this year. And I missed the actual single flowering day on a few occasions, so sometimes I just saw them the day past their flowering, and the photo below shows what they look like then. We are looking at trying to be more accurate in knowing which day they will flower as it is very much a factor of overnight temperature, but that is a topic for another post.

Most were single blooms, but I did see a couple of double blooms. No triple blooms that I saw this year.

Another orchid that isn't nearly as rare, but still not a common species, is this next one, the Great Plain's Ladies' Tresses, which was at its peak in late September. The individual flowers don't last long, as you can see from this next photo, as the lowest flowers are already finishing up while the uppermost ones haven't begun to open. The unusual warmth at the time likely had some role to play.

And finally, just an update regarding my book 'Life on a Sandspit'.

I have expanded the locations where it is available. People have already been purchasing some for Christmas gifts! 

The locations now include the following:

Bayview Market, Rondeau

Book Brothers, Chatham

Mindful, Blenheim

Mitton's Jeweller's and gifts, Ridgetown

Five-Eau, Erieau

Molly and OJ's, Erieau

Sydenham Field Naturalists, Wallaceburg

Friend's of Rondeau, Rondeau Visitor Centre (although very reduced hours, and that gift shop may be closed until the Christmas break)

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A highly endangered native orchid

One of the highlights of my season, is to check on one of the rarest orchids in Canada. It is so rare, that it was first discovered in a privately owned woodlot in Essex County as recently as 1950, and a few years later was noted in Rondeau Provincial Park. In spite of periodic monitoring, the Essex County population may no longer exist, resulting in the only Canadian population being at Rondeau.

The orchid I am referring to is a tiny, diminutive and difficult-to-see native species with the common name of Nodding Pogonia, a.k.a. Three-bird's Orchid  and a scientific name of Triphora trianthophora. And this is what it looks like up close.....real close.

Nodding Pogonia

It is quite a pretty little thing, with the emphasis on little, especially if you find one that has that magenta tinge to the petals. Most specimens are white, but I am always attracted to the magenta ones when I can find them. Some years there are hardly any magenta ones with predominantly white ones being all there is to see, such as this next one.

I have had the privilege of following this plant population ever since 1973, when it was first pointed out to me by my naturalist colleagues during the first summer I was on the seasonal naturalist staff at the park. The numbers have fluctuated greatly over the decades, perhaps partly because it is so tiny and difficult to see especially when it isn't in flower, which is most of the time. During one of the best years for it in the mid 1980s, I counted more than 1400 plants, which was amazing. The 2008 year was probably the second best year I have noted. The poorest year was in 2012 when, although I found a couple of dozen plants, absolutely none produced open flowers and therefore none produced seed. I have had study plots set up for this population ever since 1986 and have monitored the population almost annually.

Look at the next image.

Make the image as large as you can, and count how many Nodding Pogonia plants you can see. Do you see any at all? This photo was taken with a standard focal length lens, from only a couple of feet away, which is a lot closer than you would normally be viewing the ground flora at. This is what the plant looks like most of the time, for reasons I will explain shortly. In actuality, there are about 15 plants in this cluster!

Did I say that this plant is little? The average height of this plant is no more than 12 cm, or about 4.5". The flower itself, when fully open, is typically less than about 2 cm high. There are usually only one or two small, roundish leaves, each of which is less than 1 cm in diameter. Clearly macro photography equipment is required for this diminutive denizen of the Rondeau forest!

It puts out, in a good year and if it is a healthy plant, about three flowers over the course of the season (hence the Triphora trianthophora, the latter epithet meaning three flowered). The greatest number of flowers I have ever seen on a single plant over the course of the season was 7. Many flowers only put out one or two, and it is surprising how many grow but do not put out any flowers at all! The next photo - one of my favourites -  shows a very rare occurrence, with three flowers on the same plant being open at the same time. And a magenta one at that! This was taken in August of 2008, the most recent year when there was a fabulous showing of the species at Rondeau and included a few magenta ones to choose from.

The earliest I have ever seen a flower was on July 31, and the latest I have seen one is about September 20. However the peak of flowering is about the third week of August.

A bit earlier I mentioned that the plant is in a non-flowering condition for most of the time. It has a very curious flowering strategy. The plants will develop flower buds at their own pace, but will not open right away. Instead they will remain unopened, waiting for an environmental trigger. When there is a significant drop in night-time temperature, then usually on the morning of the second day to follow, all of the flower buds that are at a certain stage of readiness, will open. They will remain open for only a day (or less if they are pollinated sooner), then close up. If they are pollinated, then seed development begins, but if they are not pollinated, they will dry up and that is the end of it......there are no second chances!

The next set of buds will develop, and after a similar weather related trigger, will open several days after the first set opened. Often that is at least a week later, but it all depends on the weather.....those cool August nights are highly beneficial to this species. The benefit to this flowering strategy is that since the plants are not plentiful, if they are all open at the same time, they are more likely to attract pollinators and be successfully cross-pollinated. Of course it begs the question: why don't the flowers remain open for more than a day, as most other plants do? This would increase the rate of pollination, one would think. I haven't come across any explanation for this one-day flowering, so as far as I know, it remains a biological mystery.

This next photo shows a nice magenta flower in peak condition. There is another flower bud (the lowest one) that opened a few days before, and another developing flower bud that will hopefully open in another few days.

The plants may be scattered singly or in clusters. Here is what a small cluster may look like when opened. This photo was taken with a 100 mm macro lens, from a distance of about 2 feet. They are certainly more visible here than in the third image of this post. But in the dappled light of the forest floor, even when they are in flower they can be next to impossible to see. They are very small!

Some other interesting aspects of this tiny orchid include:
-they don't have roots like many other plants. Instead they have a tuberous root that is situated between the leafy humus layer and the sandy soil. They have a very close association with mycorrhizal fungi, which is established in the leaf mould, from where they get some of their nutrients.
-the main pollinators are small bees of the Halictidae family.
-adequate moisture well before the growing season is highly important to support the mycorrhizal fungi as well as the plants themselves. In dry years, as it was in 2012, flowering is greatly diminished or even non-existent.
-these plants can be dormant for quite a few years. Even in the heart of their range, in the southeastern US, colonies or at least parts of the population can be dormant for several years at a time. More than one population which was believed to be gone, has re-appeared.
-after a flower has been open, it droops (hence the Nodding aspect of its name). If it has been pollinated, the seeds develop, and when the seeds are ripe, the seed capsule will extend straight up. Eventually the capsule will split at several points, allowing the extremely tiny seeds to escape and be carried away by even the gentlest breezes. If the seeds land on a suitable substrate, a new plant may begin.

Now that I have you all excited about this plant, I have some unfortunate news. You probably won't get a chance to see it.

Due to its extremely limited occurrence in Canada, its extremely erratic flowering behaviour, its diminutive stature (did I say it was very tiny?), and the strong likelihood that even careful visitors could inadvertently trample it, the small area where it occurs is not accessible to the public. It is well off the beaten path and difficult to access in the first place. It is legally Endangered, under both the federal Species At Risk Act (SARA) and corresponding provincial Endangered Species Act (ESA). Due to the highly protective intent and language of those pieces of legislation, great efforts are being made by Ontario Parks staff to ensure that no harm will come to this important element of Rondeau's, and Ontario's, flora.

So even if you never get a chance to see this wonderful little plant in real life, hopefully you can enjoy knowing a little more about it via this post, and know that it is still present at Ontario's second oldest and most species rich provincial parks.

Rich forest habitat near the Triphora population