A Botanical Hotspot Where Two Rivers Meet

Sometimes we Thursday Naturalists find a spot so rich in botanical bounty, we want to explore it more than once during the growing season.  That's why our group of botanizing buddies reconvened this week at Canal Park in Rensselaer County, near Lock 4 of the Champlain Canal, a site we had visited earlier this summer, in mid June.  Among our local flora, lots of changes will happen over the course of two summer months, and that's what we were there to discover this past Thursday. And we were not disappointed!

Canal Park is situated right where the Hoosic River enters the Hudson River, and it offers trails through the shady woods as well as along sunlit waterways and down onto an alluvial plain where many plants grow to remarkable size in the silt-enriched soil.  Eager to reach the sunnier parts of the park today,  we attempted to hurry ourselves along the shady first leg of the trail, where trees like this spreading Black Birch cling tenaciously to the steep banks along the canal, upstream from where the canal rejoins the Hudson.

Our pace was slowed, and occasionally halted, by our desire to enjoy such trailside sights as the abundance of mosses carpeting the banks. I was particularly delighted by this lovely mix of Brocade and Broom mosses (Hypnum imponens and Dicranum  scoparium). We were privileged to have our own bryophyte expert, Nancy Slack, along with us today to help us put some names to the wonderful variety of mosses we found.

The cute little yellow flowers of Agrimony (Agrimonia gryposepela) were quite visible in the dimly lit woods, but I was drawn to peer at the wee little spiky seedpods along the arching stems.

I admit I was totally puzzled by what these fine-leaved budding plants could be, until I remembered finding lots of the small purple flowers of Slender Gerardia (Agalinus tenuifolia) blooming here later in the summer.  Aha!  Of course!

We remembered seeing pretty white flowers on the Deerberry shrubs (Vaccinium stamineum) in June, so now we looked for the equally pretty pale-aqua fruits that are dotted with white.  And we found them in abundance!

Here was a genuine puzzler!  I recognized the frosted-green leaves of Pussytoes rosettes (Antennaria sp.), even though I was not sure of the particular species.  But I WAS sure that Pussytoes bloomed in early spring, so I knew that those pale, greenish-white, cone-shaped growths were not new flower buds.  They reminded me of the pine-cone galls that form on willow twigs, so I am going to assume that these growths are also galls.  And rather pretty galls, at that. They resemble tiny, frosted, pale-green roses.

With Google's help, I identified two insects whose larvae form galls on plants of the Antennaria genus. I wonder if one of them made these. The Everlasting Bud Midge (Asphondylia antennariae) or the Everlasting Tebenna Moth (Rhopalomyia antennariae)? Anybody know?



Here's where we emerged from the woods and stepped out onto the sunlit shore.  From this distance one would never guess how many interesting plants were blooming among all this greenery.

Canal Park is known to be home to at least three species of Bush Clover (Lespedeza spp.), but this Hairy Bush Clover (L. hirta) was the only one blooming today.  You have to look close to see its wee little rose-splashed white flowers.

Here's another flower it would be easy to miss if you weren't searching for it among the surrounding grasses.  This is Whorled Milkwort (Polygala verticillata var. ambigua). Despite this flower's common name, many of the plants we found here had alternate leaves as well as whorled ones, which is why we believe it is the variety called ambigua, which is known to have alternate leaves.

We found several species of Tick Trefoils today, but only this Showy Tick Trefoil (Desmodium canadense) was sporting these beautiful purple flowers.

Damp riverbanks will almost always be home to a number of Lycopus species, Mint-family plants that grow wreathes of tiny whitish flowers along the stem in the leaf axils.  The sharply toothed and lobed leaves of the one pictured here convinced us that this was L. americanus, known by one of its common names as Water Horehound.  I like that common name because I can associate sharp teeth with the word "hound."  Whatever helps!

Here's another Lycopus species, L. virginicus, distinguished by its toothed but not lobed leaves and the dark purple tinge of its leaves.  Its common name is Virginia Bugleweed.

This looks like one of our native sunflowers, doesn't it? But strictly speaking, it's not.   False Sunflower is one of its common names, while Oxeye is another.  Heliopsis  helianthoides is its scientific name.

The most distinctive feature of Oxeye that distinguishes it from a true sunflower is the presence of fertile rayflowers, in addition to fertile disc flowers. At this stage of the plant's maturity, we had to dislodge one of the ray flowers (what most folks would call petals) in order to discover both the seedpod attached and the tiny pistil, withered almost beyond recognition by now.

Here's another plant that prefers the damp soil along waterways or in wetlands.  It's called Ditch Stonecrop (Penthorum sedoides), and it has the cutest little chubby flowers that are ringed by their anthers, giving them a kind of spiky look.

If peered at closely, the individual florets of Narrow-leaved Mountain Mint (Pycnanthemum tenuifolium) are pretty little white flowers dotted with purple.  But I will admit that, from this distance, the plant has a rather untidy look to it.

The bright-purple flowers of this Monkey Flower (Mimulus ringens) looked pretty from any distance.

But again, you had to peer really close to appreciate the cute little dangly flowers of Turkeyfoot Grass (Andropogon gerardi).  Also known as Big Bluestem, this is a Great Plains grass that also makes its home on eastern savannas and sunlit river shores like this one.

Of the three native Bush Clovers known to grow in this park, this low-growing weak-stemmed species called Creeping Bush Clover (Lespedeza repens) is the one I'd most hoped to find in bloom, since this one is classified as a Rare species in the state.  I will just have to come back again, to see its pretty purple flowers.

There was lots more to see at this sunlit junction of the two rivers, but we still wanted to visit the low alluvial site upstream on the Hoosic before the day was much further along. When we got there, we were surprised to see how much of the rocky river bottom was now exposed by low water.

Back under the towering Cottonwoods and Sycamores that thrive in this floodplain, the Ostrich Ferns (Matteuccia struthiopteris) had grown to gigantic size in the rich alluvial soil.

Here, too, we found Green Dragon plants (Arisaema dracontium) that reached to our waists.

Way down beneath those gigantic Green Dragon leaves, we found clusters of green berries that will later turn red as the summer proceeds.

While we had to look DOWN to find the Green Dragon fruits, we had to look UP to see the super-tall Joe Pye Weeds (Eutrochium maculatum) that thrive along this shore.

And talk about BIG!  See how huge are the achenes (seedpods) that top the stems of Great St. Johnswort (Hypericum ascyron), each one about the size of a Chinese dumpling.  When in bloom, the flowers of this native species are also huge, for a wildflower.

Although the American Germander (Teucrium canadense) here was starting to go to seed, we could still find enough of its pretty pink florets to note the curving anthers and lack of an upper lip, features that distinguish this native Mint-family plant.

Hemp Nettle (Galeopsis tetrahit) is another Mint-family plant that thrives at this site.  An introduced species, it usually grows to about knee high, but here in this rich bottomland the plants grow shoulder high -- all the better to peer at its cute little flowers that look like a tiny ghost wearing a furry hood and a butterfly-wing breastplate.

Out on the shore, away from the shade of the trees, masses of the small Dogbane called Indian Hemp (Apocynum cannabinum) sprawled on the pebbles, bearing clusters of tiny greenish-white flowers.

Three different species of Smartweed also grew along this shore.  I would guess it is obvious how Nodding Smartweed came to acquire its common name.  Persicaria lapathifolia is its scientific name.

Common Smartweed (Persicaria hydropiper) can be immediately recognized by the intermittent blooms along its flower stalks, but an even more positive distinguishing feature is that those florets have only four petals. The other smartweeds growing here have five-petaled flowers.

Here's one more smartweed that populates this shore. This one is called Arrow-leaved Tearthumb (Persicaria sagittata), but my personal name for it is TearSHIN, suggested by my having once had to force my way through a thicket of it while wearing shorts.  Its sharply barbed stems really can tear your flesh, whether of thumb or anywhere else. And then your flesh will smart!  Keep your distance, but do peer closely to note the cute little clusters of closed and open flowers.

Okay, here is a real beauty of a flower, almost hidden among the shoreline grasses and sedges and cattails.  This is Great Blue Lobelia (Lobelia syphilitica), one of our loveliest native wildflowers.

Another blue native wildflower, called Mad Dog Skullcap (Scutellaria lateriflora), inhabits these damp shores.  This species is distinguished by its small flowers that grow on long, one-sided racemes extending from the leaf axils.

With so much of botanical interest to engage us here and for so long, I and my Thursday Naturalist friends decided to call it "lunchtime" and head back to the park's picnic area before we had a chance to explore these steep shale banks along the Hoosic.  But I had come here the day before to preview our walk, and I DID explore these banks then.

Probably the prettiest plant to populate these shale crevices was Harebell (Campanula rotundifolia).  It has very slender stems that allowed the flowers to wave in the breeze, so I had to hold it steady in order to take its picture.

Out on the sunny south-facing shore, masses of Tansy (Tanacetum vulgare) had sprouted from the flat riverside rocks.  An escaped garden herb and not a native species, Tansy nevertheless attracts many pollinators, including this amorous pair of Goldenrod Soldier Beetles.  They didn't seem to care that these golden blooms were not really goldenrod. I guess they had other things on their mind!

Another insect drawn to the Tansy blooms was this tiny dun-colored moth, clouds of them flitting and fluttering about the flowers and only occasionally landing long enough for me to get a picture. But this was moth bonanza!  Look at them all!  I'm still waiting for BugGuide.net to answer my query about what species they are, but I think they might be one of the aquatic moths of the Petrophila genus.  Moths of this genus frequent riversides, since they lay their eggs in flowing water and their larvae feed on aquatic plants.  And as their genus name suggests (it means lover of rocks), they sure did appear to love this rocky shoreline of the Hoosic River.

To learn more about this fascinating moth, here's a link to the post where I got my information about it:  https://uwm.edu/field-station/two-banded-petrophila/



Here was a plant I was NOT happy to find:  A big patch of the terribly invasive European Water Chestnut (Trapa natans).  When I return to Canal Park in a couple of weeks, hoping to find those bush clovers in bloom, I think I will bring some big plastic bags and remove as much as I can.  As this photo reveals, the water is so shallow here I can easily wade out into the water and grab that nasty stuff. Hopefully, before it produces its sharp spines.