Foiled Forays For a Rare Fleabane

Most folks know what Common Fleabane is, right?  Little daisy-like flowers with petals as fine as eyelashes, usually white but sometimes a little bit pink.  It grows in vacant lots and open meadows and along roadsides everywhere.  Erigeron philadelphicus is the scientific name for this very common native wildflower.  Well, I learned very recently that there is a super-rare variety of E. philadelphicus called Provancher's Fleabane (E. philadelphicus var. provancheri). It is shorter than the standard variety of Common Fleabane, and its rosette of basal leaves persists throughout the blooming time and it is not as hairy as the standard variety is.  Its typical habitat is rocky riverside shorelines or cliffs. I frequently paddle a section of the Hudson River that has sections that fit that description.  Might we find it there?

That was the question I received from Rich Ring, rare-plants monitor for the New York Natural Heritage Program. Rich's particular responsibility regards the rare plants of New York's state parks, and this section of river is part of Moreau Lake State Park.  Rich and I arranged to meet this past Wednesday (July 1) to search the Hudson River below the Spier Falls Dam at Moreau.  We certainly had a beautifully calm river when we set out to conduct our search. Here's the Hudson looking downstream from our launch site.

And here's the river looking upstream, where some little islands with rocky shorelines might provide  the habitat required by this small, endangered fleabane. We headed both upstream and down to explore these islands and other rocky sections of riverbank within the catchment between the Spier Falls Dam and the Sherman Island Dam a couple of miles downstream.

And here's the river about 10 minutes later, when the sky opened up and dumped more rain than I had ever considered possible.  My canoe filled up with water so fast I feared it would sink, so I beached my boat, turned it over, stood under a tree, and waited for the deluge to lighten up.  It took a long time -- well over half an hour without the slightest abatement of the downpour. But eventually the rain did stop, and we continued our explorations.

Well, we never did find that Provancher's Fleabane.  This plant prefers calcareous rock like marble or limestone, and most of the bedrock along this stretch of the Hudson is granitic, an acidic rock. Sure, we felt a bit disappointed.  But the sun had come out, the sky had turned blue, and we were on a beautiful stretch of river lined with forested banks and lots of other interesting plants. We even chanced upon an American Chestnut grown mature enough to produce its graceful spikes of fragrant white blossoms.  That's not a sight we can see very often!

This was one of the more colorful patches of bloom along the banks: an abundant growth of feathery-flowered Tall MeadowRue entwined with the rain-battered pink blooms of Hedge Bindweed, both native wildflowers.

Our paddle completed, we had a second disappointment this day, when we decided to check a nearby roadside location where we once had found a very large population of another endangered species called Large-leaved Avens (Geum macrophyllum).  Would you believe, at the very same site where we had counted over a hundred specimens of this plant just two years ago, this time we found not a ONE?  Oh well! At least this search had placed us within the proximity of hundreds and hundreds of Red Raspberry bushes, with many berries perfectly ripe and ready for the feasting.  Thank heaven for small favors!

On Saturday, July 4, I continued the search for Provancher's Fleabane along another stretch of the Hudson River, paddling alone.  This section, which lies above the Spier Falls Dam, is known to have a calcareous talus slope along the east bank, so the habitat might be more hospitable to this rare wildflower, which prefers a lime-rich substrate. The day was glorious, although quite hot.  I was glad to be on the water, which I shared with this family of ducks.

Well, if there's calcium in the rocks that tumbled down the eastern banks, I never found much  evidence of it in the riverside flora.  No definite calciphiles like Maidenhair Ferns or Spikenard did I see. I did, however, find a nice big clump of Large Sundrops (Oenothera sp.) with big showy yellow flowers.  It had quite a hairy stem, so it could have been O. pilosella, which is known to prefer calcareous wetlands.

But then, only a few paddle strokes along the shore from those Sundrops, I came upon this cluster of Rose Pogonia plants (Pogonia ophioglossoides), a plant I usually associate with acidic bogs. I have heard, though, that this pretty little orchid does tolerate soils with a higher pH than those typically found in bogs.  I would have described this habitat as a wet shore.

One of New York's most common native orchids, Rose Pogonia is also one of its prettiest.

As the afternoon wore on, even the cool water beneath my canoe could not overcome the sweltering heat of the sun bearing down on the eastern shore of the river, where I had been paddling for a mile or so.  So I scooted across to the west bank, shaded now by the high hills that rose from the banks as well as by the overhanging trees.  Among those overhanging trees were several American Hornbeams (Carpinus caroliniana) dangling seedpods that resembled stacks of angel wings.

It was much cooler here, and the shoreline was much swampier, too, than the rockier eastern shore. This large patch of Sweet Flag (Acorus calamus) protruded out into the river, inviting me to search among its single-veined spiky leaves to see if I could find its distinctive spadices.

Indeed, I did find many of the Sweet Flag's sausage-shaped spadices, but what also drew my attention here was this dragonfly, having only just emerged from its exuvia,  the cast-off skin that had covered it during its nymph stage. I cannot determine the species of a dragonfly at this stage, since it has yet to develop the colors of its fully mature existence.

UPDATE: Steven Daniel, a friend with much greater knowledge about dragonflies than I have, has sent the following information to me:  

"Your dragonfly is a female Stylurus (hanging clubtails).  All clubtails (Gomphidae) are easily told by the eyes that are separated by a bar, easily seen in your pic.  Stylurus are mid-late summer dragonflies, typically in rivers, and the only genus expected to be emerging now in our area.  I’m pretty sure it is S. spiniceps (arrow Clubtail) which I had emerging in a river near here on Friday.  Note that the last segment easily visible (there is a tiny one behind it - is notably longer than the one before (in dragonfly aficionado talk we say S9 is longer than S8), which is one distinguishing feature of S. spiniceps, even as a teneral that hasn’t developed its colors as yours.   Some years I see huge emergences of them.  Here is a pic I took the other day https://www.inaturalist.org/observations/51859488"

Here was a second exuvia, this one remaining where it had attached to a Pickerelweed leaf.

And like the dragonflies, the Pickerelweed flowers (Pontederia cordata) were only just emerging in the shallows.

I delighted in the various colors and textures of the plants that crowd this marshy shoreline. Here, Tussock Sedge with its gracefully arching stems and Sweet Gale with its marvelously fragrant leaves vie for space on a hummock at the base of a tree.

Again, no Provancher's Fleabane could I find along this stretch of riverbank above the Spier Falls Dam.  But any disappointment I may have felt was certainly assuaged by the gloriousness of the day and the beautifully varied flora I did find along the banks.  And to top it all off, this Belted Kingfisher actually stayed put long enough for me to grab its image, however blurry.  In all my previous experience, this exceedingly elusive bird has always swept far ahead of me as my boat approached its perch. Today was my lucky day!