(author on her way to launching her kayak – its to the right)
After having missed a summer kayaking I was overjoyed when I finally slid my little blue otter into the waters of North Pond this year.
It was a blue and gold day when I paddled out to see if the rose pogonias were still in bloom in the bog at the southwest end of the pond. These delicate pink and white native orchids with their fringed tongues that rise above a rich sphagnum moss community are a sight to behold for any orchid lover. I was amazed by this year’s abundance of flowers.
Attaching my line to a couple of cattails so I could drift and contemplate this marvelous boggy neighborhood, I was initially struck by the sheer diversity of plants that inhabited the nitrogen poor ‘island’.
That’s when I saw the pitcher plant flowers. Why is it that I am so enamored by these solitary dark crimson and green flower spikes? Perhaps because they seem so improbable in an otherwise low growing community of plants, except for a few, none of which tower over the pitcher plant inflorescences except for the occasional swamp maple and cattails. After examining one perfect five lobed flower with its central starred balloon like center I looked for its companion, the pure white flower of the diminutive sundew, also held high above tiny rosettes of sticky red clusters, but they had already gone by.
For the millionth time I wondered why it was that these two carnivorous plants grew in such close proximity to each other. I suspected some kind of mutualism or relationship must occur between the two, one that benefited both plants, but had never found any research to support this idea. I did know that the flowers of the two carnivorous plants, held high above the plants on stalks prevented the carnivores from trapping those insects that would pollinate them, an adaptation like most, that always amazed me. Both kinds of flower heads followed the sun, that is, they were heliotropic.
I pulled myself in close to the bog to inspect both the pitcher plant and its friend the sundew with my usual curiosity. Carnivorous plants occur in locations where the soil is too poor in minerals and/or too acidic for most other plants to grow (although in this seemingly diverse bog one might argue that point). The pitcher and sundew have evolved traps to lure, drown and digest animal prey to supplement nutrient-poor soils, providing us with a perfect example of the complex relationship between plants and the places they grow. Both are deadly traps for mosquitos.
The pitcher plant consists of a group of hollow, reddish-green leaves, each connected to a stem that extends roots downward into the bog. Each “pitcher” has an upper, flared lip that has hairs that curve downward and is generally partially filled with water. Insects attracted to the pitcher crawl inside the modified leaf and are prevented from leaving by the downward pointing hairs. Eventually the insects tire and fall into the water where they are digested for the most part, by bacteria. The products of digestion, high in nitrogen and containing amino acids, are absorbed by the leaf, supplementing photosynthetically produced organic matter. The water contained by the leaves supports a community of interesting organisms that include bacteria, protozoa, rotifers, and other creatures. In some places pitcher plants even devour spiders, salamanders, and small frogs.
The round-leaved sundew has a number of small rounded leaves attached to a central stem. The modified leaves form a sort of rosette. Each leaf has glandular hairs around its edge and most leaves have a drop of a sticky substance attached to the end of each hair. Insects like mosquitos and ants become trapped in the drops. When they try to escape their frantic motions cause the leaf to fold over the insect. The whole process takes about 30 minutes. The prey is subsequently digested and the digested nutrients, also containing essential nitrogen and amino acids, are absorbed into the plant, supplementing the food produced photosynthetically.
Amazing, don’t you think?
Another observation suddenly occurred to me while I was examining the two plants. Both plants were primarily reddish and green. This color correspondence might be another clue supporting my idea that these two plants benefited from each other in very specific ways…
Suddenly my eye caught the loon floating high and then sinking in the water nearby. This one was fishing. The loon dipped his/her head and bill into the water searching for fish with his very red eye that come fall would turn gray for the winter. The red eye, it is believed, filters out blue and green light making for more effective summer fishing. The brilliant red may also help a loon attract a mate.
The dark shadow on the water caused me to look up into a late afternoon sky, just in time to see the white eagle’s tail. A top predator was flying over my head. And it was late.
Reluctantly, I decided to paddle back to the dock. Hours had passed while I was enthralled by what I had seen at the bog and my never-ending unanswered questions.