Tuesday, September 18, 2018

The Dwarf Bulrush Hunt Continues!

So what's the big deal about this wee little non-showy plant shown above, the Small-flowered Dwarf Bulrush?  Well, New York State has listed Cyperus subsquarrosus (that's its scientific name) as one of the state's rarest plants, placing it in the category of Endangered.  But as I recounted a few posts back, a state rare-plant monitor and I discovered uncountable numbers of it growing along Moreau Lake, and that was just on one small portion of the lake's shoreline.  On another day, I returned to Moreau Lake State Park and explored the whole eastern shore of the lake, finding comparable numbers there.  Then once again, on a day  pouring rain, I walked the rest of the way around the lake, and I found so much of the Small-flowered Dwarf Bulrush that I feel confident in declaring it grows all around the lake on every shore that is sandy or pebbly, its numbers declining to few or none wherever the shore becomes mucky or where tall vegetation grows out into the water.  This blog post documents my walk around the lake on that rainy day, September 9, 2018.

I started my walk on the southern end of Moreau Lake, just past the boat launching site, proceeding clockwise.  I could see lines of vegetation marking how low the water in the lake has fallen these past 3 or 4 years, possibly exposing a seedbank of our plants that had been waiting underwater all that time, ready to grow when exposed once more to sunlight and air.

Sure enough, as soon as I passed the area that groomers keep clear of vegetation,  I began to see our little Dwarf Bulrush (which, by the way, is a flatsedge and not a bulrush).  I included the toe of my shoe in this photo to show how truly tiny it is, which may account for why it may have been overlooked for many years.  It was last reported from Moreau Lake in 1961.  That's 57 years ago!

As I continued, I soon discovered how very happy Small-flowered Dwarf Bulrush was to inhabit this shore.

But it liked this shore only so long as the habitat remained sandy or pebbly.  I soon reached a muddy area where cattails crowded into the lake,  and the plant promptly disappeared.

I continued my walk along the western shore of the lake, passing through a flat area just teeming with shoreline plants, including vast numbers of Spotted Jewelweed (Impatiens capensis) dangling their bright-orange flowers.

There were many other colorful flowers here, including this Blue Vervain (Verbena hastata) with just a few of its bright-blue flowers remaining on the stalks.

Despite the rain that started falling more heavily now, masses of Sweet Everlasting (Pseudognaphalium obtusifolium) were still attracting lots of bumblebees and wafting the delightful smell of maple syrup on the humid air.

The deep-pink flowers of Small-flowered Gerardia (Agalinis paupercula) added points of bright color to the tangle of vegetation.

I was truly surprised to find these vivid blooms of New York Ironweed (Vernonia novaeboracensis) sharing its space with bright-yellow plumes of goldenrod (species un-determined).  This species of Ironweed, although not really native to Saratoga County,  has been planted in a nearby rain garden near the park's nature center, so I imagine that seeds from that garden could have made their way out here to the shore.

The flattened scarlet stems of this plant created carpets of brilliant color out here on the shore, and at first I couldn't imagine what species they might be.

But a closer look revealed the narrow leaves and ruby-red seed pods of what could only be Canada St. John's Wort.  But these plants were so much larger than the Canada St. John's Wort I usually find (Hypericum canadense), I wondered if they could instead be the Greater Canada St. John's Wort (H. majus)? I will have to consult some of my botanist friends to find out.

Update: I recently showed this Hypericum to noted botanist Jerry Jenkins, and he had no doubt at all that this was indeed Hypericum canadense and NOT H. majus. So that settles that!

Nodding Bur Marigold (Bidens cernua) is one of the prettiest plants that Nature saves for the last days of summer, and I was delighted to find it thriving here among all these other native wildflowers that crowd the muddy flats along the lake's western shore.

Down near the water where a tiny stream entered the lake, an area of bright-green reeds was starred with the brilliant white flowers of arrowhead (Sagittaria sp.).

I spied one arrowhead plant growing out in the rain-dimpled water, and now I could discern the distinctive narrow leaves of Grass-leaved Arrowhead (S. graminea).

Approaching the park's swimming beach, I knew I would find no plants of interest there on the bare-raked sand, so I hurried along to cross a bridge and reach the lake's northern shore.  Here again, I could see lines of vegetation lining the damp sand.  Would our little flatsedge resume its place here?

Oh yes, it sure did!  And oddly enough, it thrived here the most abundantly among the stems of a sparse patch of Phragmites, one of the most invasive species found on the lake.  I'm sure as the Phragmites patch grows denser, the Dwarf Bulrush will like this spot less.

But not to worry!  Even if the Phragmites should drive our Cyperus subsquarrosus completely off the north shore, there would still be uncountable numbers of this Endangered species thriving along the eastern shore.  The stretch of eastern shore pictured here is more stony than sandy, but that did not discourage our little flatsedge one bit.  It seems just as happy to grow in pebbles as it does in sand.

By this point, both the flatsedge and I were getting soaked by the rain.  I'm sure the plant didn't mind the rain, but I was getting cold and tired.  Happily, I had reached the point where I had completed my circuit of the lake. Now I could call it a day and return to my car, knowing that Cyperus subsquarrosus (perhaps better known by its previous name Lipocarpha micrantha) was not endangered at all along the shores of Moreau Lake.


Lynn's mom said...

Your trip, the photos, your words: all such a bright spot in my day. Thank you for caring so much about these woods and waterways and letting us all know what you've found.

The Furry Gnome said...

That's a lot of interesting plants!

threecollie said...

What a neat trip! And thanks for the bur marigold ID. Saw some recently and wondered.