Pink Lady's Slipper Orchid at Hammond Pond

Pink Lady's Slipper Orchid (Cypripedium Acaule)

 Ever since I got my National Audubon Society's Regional Field Guide (so far my only non-bird field guide) and learned of orchids native to the US, the idea of searching for these beauties has captured my mind. I assumed that such amazing plants and flowers as these orchids could only be in remote locations such that I would never be able to find them. Then I moved here and started reading Suzette's blog, Bird News of Nahanton Park, to learn that at least one native orchid, the Pink Lady's Slipper, can be found in our local Newton, MA parks. For some reason I was never free in the spring to explore the park while the orchids are blooming, so I was very excited when my neighbor had told me that she had just seen some orchids at Hammond Pond.

So last weekend, after some time at work, I dropped by Hammond Pond and Webster Woods and headed into the woods in search of orchids (and of course a few birds too) with my camera and tripod. Back in the woods, I was lucky enough to not only find two flowering plants, but also what I think was a third plant that did not have a flower spike. The flower is so amazing that it gives this orchid its name. Cypripeduium acaule, commonly known as the Pink Lady's Slipper or Moccasin Flower is named for the pink pouch (In the Cypripedium orchid sub-family, the labellum forms this pouch) that superficially resembles footwear (though I think other Lady Slipper Orchids have more of a slipper appearance).

Cypripedium acaule

I was inspired by my encounter with these Pink Lady's Slippers to read more about these amazing plants of our suburban wild lands. I think the coolest thing I learned about them was their method of pollination. On the front of the pouch, where it folds in, is actually a trap door (best seen on the top picture). Only strong species of bees are able to push their way into the pouch as they are drawn to the flower by its color and a faint sweet odor that the bees associate with nectar. But once the bee forces its way inside the pouch, he finds that there is no nectar or reward and he cannot exit the same way. Instead the pouch forces the bee to climb up the inside of the pouch towards the top. This top opening of the pouch is partially obscured by the column (which contains the stigma and pollinium) and the staminode (a more burgundy flap on the column). As is visible in the picture to the right, the column and staminode create two routes out of the pouch through which the bee can make his escape. As the bee exits, his back comes into contact with the yellow waxy ball of pollen (also visible in picture). Now this bee being a smart bee, will most likely have learned that the Pink Lady's Slipper flower has nothing he is interested in and traps him to boot. And thus the bee will not make the same mistake twice. But if we and the Pink Lady's Slippers are lucky, then this bee will be of the adventurous variety and will, against logic, visit a second Pink Lady's Slipper. While he navigates this trap and maze once more, this time the pollen already on his back will adhere to the stigma of this second flower just before he reaches the opening to have yet more pollen deposited on his back. (There is an excellent blog post here with a photograph labeled with the bee's route through the flower)

Cypripedium Acaule

Because most bees are likely to quickly learn to avoid Pink Lady's Slipper flowers, only about 5% of flowers are pollinated in a given year. This may actually be advantageous as seed production is very taxing to the plant. But to make up for this dismal pollination rate, Pink Lady's Slippers can live on average for about 20 years! Their low pollination rate, long life span, and very specific habitat requirements makes it very important to not disturb these orchids so that we can protect our native population.

I have to say that I look forward to observing these Pink Lady's Slipper orchids in the future and one day I'll have to venture forth in search of more of our wild orchids.


P.S. I did mention I was looking for birds too. Some of the best finds were Great Blue and Green Herons, Cedar Waxwings, Red-eyed Vireos, a Great Crested Flycatcher, and for a few seconds I had a great view of a stunning male Rose-breasted Grosbeak!