Living on the edge
By Alyssa Nyberg
When we go for a walk in our woods, my daughter runs ahead and shouts out, “Mom, look, a moss!” We get down on our knees, feel the soft carpet of leaves and admire the moss’s green beauty. She has found a hair cap moss (Polytrichum species). We share a smile and then she is off and running to the next patch of moss that she can find…and there are a lot of patches. They are growing all along the trail, on the sandy soil, on living trees, on decaying trees, on rocks, on sand. Wherever we seem to look…moss!
Personally, I find mosses pretty cool. They are wild and crazy, living on the edge, literally. Mosses live where other plants cannot. Mosses have no roots, but rather threadlike rhizoids which allow them to attach and live on horizontal and vertical surfaces that are nearly impenetrable, such as cliffs, rocks, tree bark and sterile sand.
Mosses don’t mind being short. They are miniscule as a matter of survival. They can be as small as a millimeter in height or grow to 10 centimeters in lush, shaded rainforest habitats. Mosses are small in size in order to stay within what is called the “boundary layer”, the layer of slow moving air found just above the surface of the ground, rock, tree, etc. Boundary layers differ in height depending on the surface over which the air moves, and therefore moss height will differ as well. You have likely experienced the boundary layer if you have ever lain down on the ground and watched the clouds go by. Down on the ground the air moves more slowly, and is also warmer and more humid. These are the very conditions in which mosses thrive: moist, warm areas with little airflow.
When a moss is ready to produce spores, which provide the next generation of plants, it will raise its spores up on long stalks called setae. The stalks lift the spores above the boundary layer and into faster moving air which then carries the spores to new locations.
The leaves of mosses are simple in shape, often only one cell thick to allow water and carbon dioxide to easily penetrate throughout the leaf. Leaf shape varies among the different species of mosses, from lance shaped to circular. But all mosses consist of many tiny leaves, packed in together to prevent drying and desiccation.
I admire mosses for their patience. Mosses are completely and utterly, 100% dependent upon rain and moisture in the air. They wait for rain, and if rain doesn’t come, they just keep waiting. Mosses, unlike most plants, lack vascular tissue which moves water from the roots to the leaves. (Remember, mosses do not have roots.) So, when there is little moisture in the air, like on a hot day in July for example, the moss dries up. But as evening falls and the humidity rises, the moss will rehydrate and become lush once again. Mosses can lose up to 98% of their water content and still survive. Scientists have found that they can rehydrate mosses that have been kept dry in boxes for 40 years!
Want a little bit of fun with moss? Find a clump of moss growing near your home, bring it inside, set it on a plate next to a sunny window and let it dry out. Then, when you need a little excitement, take a small glass of water and slowly, gently, drizzle it over the moss. The leaves will unfurl and turn green right before your very eyes. When you are finished with your moss experiment, return it to where you found it so that it may continue to grow.
Mosses are a plant that can be admired any time of year, spring, summer, fall and winter. You can find mosses green and growing in the heat of summer and even at the edge of snow, like my daughter and I did during our walk in the woods last week.
There are some 22,000 species of mosses on earth. Indiana is home to roughly 225 species of moss. Admittedly, I know very few of them, but am interested to learn them in the days, months, and years ahead.
Come on out to Kankakee Sands to explore the world of mosses. How many different kinds can you find? There are many mosses which grow in the shade of Conrad Station Savanna, and many which grow in the wide open prairies of the Kankakee Sands restorations. Come for a hike and admire the mosses… and of course, feel free to lie on your back and watch the clouds go by too.
The Nature Conservancy’s Kankakee Sands is 10,000 acres of prairie and savanna habitat in Northwest Indiana and Northeast Illinois, open every day of the year for public enjoyment. The Nature Conservancy in an international, non-profit organization. For more information about Kankakee Sands, click here or call the office at 219-285-2184.