July is peak orchid season on PEI, and so I am always pleasantly surprised to run into one of our late-flowering species in fall. I came upon a small patch of this lovely Yellow Ladies’-tresses (Spiranthes ochroleuca) in early October.
We have seven species of Ladies’-tresses on the Island, named for the way their ranks of flowers resemble long, braided hair. While you may have hated math class in school, you can’t escape being surrounded by physical expressions of mathematics in nature. The fractal geometry of some ferns, the predictable arrangement of plant leaves along a stem, and the Fibonacci sequence found in many flowers and seed heads are all common examples of applied mathematics. My favourite example is the helical arrangement of Ladies’-tresses.
Yellow Ladies’-tresses is native to the Island but wasn’t confirmed here until 1980. Despite being able to tolerate disturbed habitats (the one shown was growing on an old woods road), it’s considered rare in the Province and is only know from a couple of dozen locations, mostly in Kings County.
The Orchid Family (Orchidaceae) is one of the largest and oldest families of flowering plants, comprised of roughly 28,000 species and dating back some 100 million years. They’ve had a long time to evolve beautiful, complex flowers and reproductive strategies. Yellow Ladies’-tresses is pollinated by late-season Bumble Bees but is also capable of asexual reproduction, producing seeds from unfertilized flowers.
The fall flowering Ladies-tresses are the most complicated group of orchids we have, with much classification and re-classification over the years. That said, I’m particularly fond of Yellow Ladies’-tresses, with their subtle yellow colour, dense soft fuzz, and delicate curves of the top and bottom of each flower.
If you missed seeing our Island’s beautiful orchids this year, I have good news! You can find photos of some of those I found this year (and showed people during my 2023 field workshops) in these two blog posts here on PEI untamed: