Checking in on Rare Plants at Moreau Lake State Park

How could it be, that in one of the driest summers I can recall, the water level at Moreau Lake remained so high for most of the season I could not walk around the lake on the shore?  And yet now, after several days of drenching rain that filled other water bodies to the brim, the level of Moreau Lake has fallen enough to reveal long stretches of sandy or pebbly or muddy shore? The cause of the rising and falling water levels in this kettle lake remain quite a mystery, but the important thing for me is that I can now walk around the lake.  Most of the way, anyway, with my feet on dry or only damp land.  And I was excited to be able to do so.  A number of really rare plants grow along this shore, and at last I could go check on them.

The first plant I went to check on was Whorled Mountain Mint (Pycnanthemum verticillatum var. verticillatum),  an Endangered species in New York State with only five other populations recorded across the entire state.  When a state rare-plant monitor assessed our Moreau Lake population back in 2014, he counted 273 individual plants thriving along the shore of a cove, making it one of New York's  most abundant populations of this plant.  How many would I find today?  Over the nine years since I first discovered this super-rare plant at Moreau, the lake has risen and fallen remarkably and many times over, sometimes completely submerging the original site of that Mountain Mint population and drowning many plants.  And now, the shrub cover has spread substantially, shading so densely the original site, the habitat might no longer be congenial for this rare plant.  As I made my way down a forested bank to the sandy shore, I was relieved when I saw one of the original patches of this plant still intact. The plants had finished flowering, but their signature spiky seedheads remained quite noticeable.  As did the strong minty fragrance they emitted when I pinched them!  Whew!  At least a few Whorled Mountain Mints still survive, still producing the seeds that could re-build the original population.

I  found very few others, though.  Maybe 20 plants in all, in two widely separated patches along the shore.  There might be more, still holding on beneath the dense shrubs that I could not push through.  But at least I did find some very healthy-looking plants, and some still retained a few of their tiny blooms.

The shoreline shrubs certainly appeared healthy, their numbers not at all diminished, but rather enhanced by the intermittent flooding.  The most abundant of these shrubs is Buttonbush (Cephalanthus occidentalis), whose perfect orbs of tiny white flowers have yielded now to rosy red seed heads.

The most abundant wildflower on this sandy shore was Boneset (Eupatorium perfoliatum), each plant abuzz with many visiting pollinators.  I recognized this Northern Paper Wasp (Polistes fuscatus)  immediately because of the two red spots adorning its yellow-striped black abdomen.  When this colonial wasp is guarding its honeycomb-like paper nest, it would be unwise to get this close to it, for Paper Wasps are known to defend their nests quite fiercely.  But away from their nests, this wasp is not at all aggressive.  And it's also likely the nests have already emptied of the young that required  defending.

Here was another visitor. Or, more likely, a regular inhabitant of this cove: a young Green Frog that was kind enough to sit still for its portrait.

My next destination was a stretch of dry sand along the south-facing north shore of Moreau Lake.  No matter how high or low the lake's waters rise or fall,  there always seems to be enough sandy shoreline here to support a second truly rare plant, this one another state-ranked Endangered species called Small-flowered Dwarf Bulrush (Cyperus subsquarrosus).  When I first encountered this wee little flatsedge back in 2018, a year when the water was very low, I found literally thousands of these tiny plants thriving on just about every foot of either sandy or pebbly shore.   Would I still find some today?

Oh yes, I sure did!  I really didn't bother to count them this year, when I saw how abundantly they were  thriving in both the dry and the damp sand along this stretch.  Even though this plant is very, very tiny, it is relatively easy to spot, with its swirly leaves of a distinctive gray-green color, two features that distinguish it from the many other flatsedges and other ground-hugging plants that share the shoreline.

This photo gives a better indication of how small the Small-flowered Dwarf Bulrush is. You can also see the little rounded spikelets that resemble tiny pinecones.  The spikelets of other flatsedge species tend to be, as might be expected, flatter than these.

Satisfied that "my" Small-flowered Dwarf Bulrushes were still abounding here, I continued around the lake, crossing over a bridge that separates the main lake from a back bay.  I was impressed by this exuberant spray of Goldenrod flowers (Solidago sp.) among the many that lined the trail over the bridge.

A single plant of New England Aster (Symphyotrichum novae-angliae) growing nearby announced its presence by the vivid purple of its large flowers.

A crowded patch of  Bird's Nest Fungus (species unknown to me) was not yet ripe enough to display the tiny "eggs" that rest in these cup-shaped "nests."  At present they resembled some miniature marshmallows covered with toasted coconut.

Now I have reached the newly walkable shore of Moreau Lake's back bay, only recently emerged from inundation. This is a muddy (rather than sandy or pebbly) shoreline that supports a wide variety of plants I seldom find along other stretches of shore around the lake.

This back bay shoreline is where I find the most abundant numbers of the native wildflower called Small-flowered Agalinis (Agalinis paupercula). This dainty purple-flowered species was until recently rated as a Rare plant in New York, but since equally abundant populations have been found, it is no longer classified as a rare species.  In my experience, though, I have not found this pretty plant, which bears its small flowers on very short stalks, at any other location I have explored but this one.

This Small White Aster is an equally abundant wildflower along the back bay.  I am surmising it is  Symphyotrichum racemosum, an aster species known to grow at this location.  But I confess I have difficulty distinguishing among several species of small white asters that can be found here.

I was happy to find a single plant of Water Smartweed (Persicaria amphibia) still blooming this late in summer.  The shallow muddy water along this shoreline is this native wildflower's favored habitat,  and  (true to its specific name) it can occasionally be found growing on the muddy shore as well as floating  on the water.

What a sweet little blue wildflower!  It's our native Small-flowered Forget-me-not (Myosotis laxa), and it is so small it helps to have bunches of them like this, in order to detect them.

This Pickerel Frog can be hard to detect, as well, for its spotted skin serves as good camouflage along this shore.

There was one more rare plant  I wanted to check on, and this one is really rare!  Until we found it at Moreau Lake State Park in 2019,  Pringle's Autumn Coralroot (Corallorhiza odontorhiza var. pringlei) had been considered to be extirpated from New York since a last sighting in 1903, way out west of Saratoga in Monroe County.   We have since found dozens of this tiny native orchid at Moreau, although this drought-ridden summer has discouraged their numbers significantly.  Although I could not find any plants on the same day I walked around the lake to check on those other rare plants,  I did find a small group of them when I returned two days later. And this time I was accompanied by noted New York botanist David Werier, author of the important botanical resource, Catalogue of the Vascular Plants of New York State.  We were in luck. The flowers had opened, revealing the single broad purple-spotted lower petal that helps to distinguish this super-rare Pringle's variety from the very common standard variety of Autumn Coralroot.

An even more significant feature of the Pringle's variety of this orchid is the fact that the florets are open, revealing the reproductive structures within (including the pollen bundles),  unlike the closed, self-pollinating florets of the standard C. odontorhiza var. odontorhiza.

This open-floret feature proved to be especially interesting to Mr. Werier, who was actually able to examine the minute interior reproductive organs through his magnifying loupe.

Mr. Werier explained to me that structural features of the reproductive organ he was able to observe could be instrumental in supporting his and other botanists' assertion that the Pringle's Autumn Coralroot is a genuine, distinctive, and definable variety.  Apparently, there is some controversy about this issue among taxonomists.

I bet if we could bring those skeptical taxonomists to Moreau Lake State Park when both varieties are fully in bloom (as they are now),  they could see for themselves how different the two varieties appear, even to the naked eye. And if they apply their magnifying loupes, they could see for themselves what Mr. Werier was quite elated to have observed.  I bet there aren't many other places, besides this location, where the flowers of both varieties can be seen blooming at the same time.