Monday, June 19, 2023

Orchids, Islands, Larval Chambers: Sunday Afternoon on the Hudson

I was alerted by a Facebook Memory that the wee little native orchid called Shining Ladies' Tresses (Spiranthes lucida) was blooming exactly one year ago this week on the shore of the Hudson River at Moreau. So that's where I went yesterday, setting off in my solo canoe to hug the river's shore.  These orchids are so small, they hide easily among the riverbank grasses.  So I stashed my paddle and inched along, grabbing rocks and branches to pull me along as close to the banks as the water's depth would allow me passage.



Aha!  Could those be my orchids, snuggled in tight between a couple of boulders?



Indeed they were!  And this year, TWO plants were sharing this narrow space.  Although the white florets were just beginning to open, I could distinctly see their yellow lower lips, a defining trait of this early-blooming species of Spiranthes.




Delighted by locating "my" orchids (and hoping the predicted rain would hold off a while),  I happily paddled further along the shore, wondering what other treasures I might find.  I drew to a halt when I spied this patch of Marsh Marigold (Caltha palustris), its showy yellow flowers long gone, but its now-split-open seedpods as pretty as any flower.


Another nearby Marsh Marigold plant held some seedpods that were not yet open, and colored a remarkable pink.




Lovely! And amusing, too. Each pod resembled a pink-backed porpoise, leaping in formation with its fellows.




I next paddled out on the river to pull up on the shore of a small island, the closest one of a cluster of four that lie in mid-river.




When I first started paddling this stretch of the Hudson, back in the 1990s, these islands were thinly forested with oaks and birches, but over the years, beavers and high water have toppled most trees except for a few pines. The habitat is now more meadow-like, with Low Blueberry, Black Huckleberry, Arrowwood and Silky Dogwood shrubs, Virginia Creeper, Royal Fern, and lots of Poison Ivy.  I'm happy to note, however, that some wildflowers still persist, including this lovely Blue Flag (Iris versicolor). And best of all, lots of Early Azalea thrives here to perfume the air in late May.




In the damper, sandier parts of the the islands, many plants of Blue-eyed Grass (Sisyrinchium sp.) abound.



Sharing the space with the Blue-eyed Grass are many bright-yellow Small Sundrops (Oenothera perennis) and scatterings of Bluets (Houstonia caerulea).


Later this summer, the flowers of several species of St. John's Wort will decorate the damp sand, and even now, the leaves of hundreds of Marsh St. John's Wort plants (Hypericum virginicum) glow ruby red when backlit by the sun. They will later have pretty pink flowers.




Uh oh!  Here's a very pretty flower that makes me very worried when I find it where native wildflowers are rightfully at home.  This is Yellow Iris (Iris pseudacoris) and it is definitely not growing where it is rightfully at home.  This iris is a highly invasive import from Eurasia and Africa, and left to its own devices, it will eventually completely supplant our native riparian wildflowers.  Well, you can be sure I did not leave it to expand its footprint here on this shore. 




One of our wildflowers that that Yellow Iris would endanger is a native orchid called Tubercled Orchid (Platanthera flava), which in other years I have found thriving by the dozen on the same river island as that invasive iris.  Not this year,  though.   Orchids are like that. They sometimes wait a few years between blooming, or they just move on.  At least I found some of their basal leaves, although they looked ratty enough to be from a previous year. Ah well, maybe next year!




I could not find any Tubercled Orchids, but I sure did find an interesting phenomenon among the Royal Ferns.  Just as I had discovered for the first time a year ago,  the tips of many fronds had been rolled into hollow orbs, secured with silk. But this year, I knew immediately what they most likely were: protective chambers where sawfly larvae can safely feed until they pupate there within.



Here's a closer look at one of these orb-shaped chambers, shaped and secured with silken threads.



After much searching on Google last year, I finally found a site that mentioned a likely candidate for the little green larva feeding inside the rolled-up fern leaves. On a site from the University of Wisconsin/Milwaukee,  I learned that "the sawfly on  the Royal and Cinnamon ferns is probably in the genus Strongylogaster, whose larvae famously enjoy ferns."


How the heck did that tiny green larva poop out so many and such big pellets of frass?! Sorry, little critter!  I did sacrifice you (but mercifully quickly) in my search for information about you.


Did I mention the larvae were tiny?



1 comment:

Steve Plumb said...

Sent back in time from 6/10/24 to see the sawfly larvae.
Always a pleasure to read about a part of the Hudson River that still feels wild.