The Carlisle Mosquito Online

Friday, May 30, 2003


Pink Lady's-slipper

Click image for larger image (photo by Kay Fairweather)
Name: Cypripedium acaule, a member of the orchid family; common names include the pink lady's-slipper, moccasin flower, and stemless lady's-slipper. The lady's-slipper gets its common name from the large pouch on the flower which apparently reminded someone · who had never seen my slippers · of the toe of a lady's slipper or moccasin.

When and where seen: Starting in May, pink lady's-slippers can be seen blooming in the woods and wooded yards around town. I have several clusters in my backyard on School Street. Those in the more open areas are large and in full bloom; others in heavier shade are still in bud. Pink lady's-slippers are quite common alongside the paths in the Towle woods. This doesn't mean that it is okay to pick them.

Protection: All lady's-slippers, including the pink one, have legal protection in Massachusetts in the 1935 "Act to Protect All Wild Azaleas, Wild Orchids and Cardinal Flower."

Distinguishing characteristics: The pink lady's-slipper has two deeply-ribbed, opposing leaves low to the ground and arranged in a V-formation like the twin cylinders on a Moto Guzzi. The leaves and the single flower stalk rise directly from an underground stem. Very rarely will a plant have two flowers. The bilaterally symmetrical flower, occasionally white but usually pink and veiny, stands clear above the leaves on a stalk about a foot tall. The pouch is big enough to accommodate a large bumblebee.

Pollination: The tricky lady's-slipper lures the bumblebee into its pouch with promising signs of nectar. The bee must first pass under the stigma where tiny barbs scrape off any pollen the bee is already carrying. It finds no nectar · just a waste of time down a one-way street along which it can't help but pick up a fresh load of pollen. For the lady's-slipper, this process minimizes the likelihood of self-pollination. But the bumblebee soon learns to avoid lady's-slippers. The payback for these deceptive flowers is a dependency on naïve bees and a low pollination rate.

Life cycle: The lady's-slipper produces a huge number of extremely tiny seeds which are dispersed by the wind. This broadcast approach increases the probability that at least a few seeds may land in a suitable place. Since the seed is so tiny, it carries no food for the embryo. If it doesn't find an acceptable soil fungus that will provide water and nutrients to the young plant, it won't even germinate. Plants develop underground for years in a classic root-fungus symbiosis known as a mycorrhizal relationship. When sturdy enough, the plants break through the surface, produce leaves, manufacture their own food (giving some back to the fungus) and eventually flower. Even when plants are photosynthesizing their own food, the fungus remains beneficial by improving the roots' efficiency in absorbing nourishment. In the wild, the process from germination to flowering can take eight to sixteen years.

Lady's-slippers in the garden: If you want these native orchids in your garden, go to a source (like Blanchette Gardens) that has nursery-propagated plants. In your own back yard beyond the arm of the law, you will find that plants transplanted from the wild rarely survive and those that do are short-lived. The severing of the fungal mycelium must be a factor.

References: James R. Peek, New York State Conservationist Journal, April 1998; Carol H. Woodward and Harold William Rickett, Common Wild Flowers of the Northeastern United States.

2003 The Carlisle Mosquito