Exploring the Mystique of the Mushroom
There is a certain mystique that surrounds mushrooms. Existing in the form of over 45,000 different species, these fungal fruiting bodies can be strikingly diverse in form. The delicate mycelium, roughly analogous to a plant's roots, can pervade vast expanses. Even so, predicting where and when the mysterious sprouting bodies will appear seems quite impossible. A combination of conditions, including temperature, humidity, sunlight, and soil, must be just right for a mushroom to sprout and thrive.
To explore the mushroom's mystery, I took an expedition into my backyard. This was the most convenient locale to do so, as I could visit it often for continuous observation. In addition, my yard teems with biological activity due to the large amount of decaying wood, including stumps and logs, from several large cottonwood trees (Populus deltoides, members of the willow family) that were cut down several years ago. Most of my yard is grassy, shaded, and slightly uneven in elevation. Numerous trees and shrubs line the edges of this plot of land, creating moist and darkened areas. Despite this advantageous environment for mushrooms, I did not expect to find much; before this expedition, I had not seen even one mushroom in the yard.
On October 1, 2002, the first day of the expedition, one of the first mushrooms I discovered was a cluster of "LBMs," or little brown mushrooms (Aurora p. 32), which remain unidentified; new species sprouted at a rate faster than I could check them out. It seemed completely pointless, and often impossible, for me to try to identify them one by one since they were so abundant, yet each had its own minute differences. Still, I guessed that these mushrooms were in the Psathyrella genus, since they seemed to match the descriptions of the common features of Psathyrella, including the distinctly delicate flesh and the tendency to grow in large groups. Upon lifting the low branches of some creeping evergreen juniper shrubs (Juniperus horizontalis), I discovered a thick carpet of tiny caps. The myriad little mushrooms completely obscured the soil beneath them. The stalk, roughly 5.8 centimeters tall, was almost translucent in color. The conical cap, about one centimeter in diameter, was dry, fibrillose, and varied from a gray to a light gray-brown color. The adnate, broadly attached gills were a darker shade of brown.
How long would these mushrooms live? Since these LBMs were under the protection of the bushes, I supposed them to be thriving, and expected them to survive for a long period of time. I was quite shocked when I found them gone the next day. The delicacy and fleeting quality of mushrooms quickly became apparent to me. I realized that it was important to record my observations as soon as I found any mushrooms, since it was impossible to predict how long they would remain. Later on, a smaller patch of the LBMs returned in the same location. I have discovered numerous similar patches all over the yard.
At first I simply recorded observations in my field journal, listing observations and characteristics rather haphazardly. Not long afterward, though, I realized that I had to come up with a method, a way of recording observations. I wanted to condense large amounts of information into something more manageable. I found that using charts to record all the characteristics of the mushrooms I documented was organized, easy to read, and neat. Furthermore, I categorized each mushroom under a group number, based on its general location in my yard. This also gave me a handy way of referring to the mushrooms I could not identify with a scientific name. With a sketch and a picture of each fungus, my directory of the mushrooms in my backyard was complete.
On the first day of my expedition I also found a pristine white mushroom. The dry cap was like a small ball on a tall, smooth, white stalk. Nowhere in my references could I find any information about a cap of this oddly spherical shape, so I temporarily named it "Number 1." Nearby were similar white mushrooms, which I named Group 3, but the shape of the cap of Number 1 was far too different to have been the same type. Imagine my surprise when the next day, the smooth, round ball of Number 1 had opened into a convex-shaped umbrella! Light brown gills were exposed, and where the edges of the "ball" had torn off the stalk, a tiny ring of flesh was left. As the mushroom matured in the following days, I realized that Number 1 and Group 3 were the same type of mushroom, Lepiota naucina. This particular incident helped me realize that mushrooms can indeed change radically in shape. I had found mushroom Number 1 in its button stage, and I had to wait to find its mature characteristics.
Another mushroom I found to be particularly interesting. The Coprinus micaceus, an inky-capped mushroom, decays in a way very different from most mushrooms; it digests its own cap with enzymes as it ages. The cylindrical caps of the younger mushrooms change shape drastically: they open up into a bell shape as they mature. They grew in three large, tightly packed clusters of about eight on a shaded grassy patch. As the mushrooms aged, the ooze that came from the decaying flesh dripped onto the grass below. This was the inspiration for a poem by Percy Bysshe Shelley:
Their mass rotted off them flake by flake
Till the thick stalk stuck like a
Where rags of loose flesh yet tremble
Infecting the winds that wander by.
The last line of this stanza refers to the millions of spores that are released when the cap disintegrates and curls back. This exposes the gills to the air so that the cap and surrounding gills do not impede the spores' trajectories.
Lignicolous mushrooms (those that grow on wood), most of which grew on the cottonwood stumps and logs, also abounded in my yard. Most of these mushrooms were quite fleshy and large. For example, a Polyporus squamosus growing in a shaded, damp area of the yard was 9.7 centimeters in cap diameter. It was the first porous mushroom I had uncovered, and I found the yellow pores fascinating. On the underside of the mushroom cap were countless tiny tubes that dropped spores into the air. It was also the first mushroom I found whose stalk position was lateral instead of central, which helps to keep the tubes even more exposed to the air. This particular specimen was relatively hardy, since its life spanned almost the entire month of October. It underwent temperatures ranging from 42.6°F to 75.8°F.
On the same stump as the Polyporus squamosus I found a few thriving Polyporus (Caloporus) pescaprae. These were also large, fleshy, and long-lived. With a tan, speckled cap and stem and white pores, it grew on the stump's exposed top where the tree had been cut. Each of these species seemed to have its own ecological niche. Years ago, the cottonwood, a living organism towering over 50 feet high, was an open system, taking in energy from the sun. When it was cut down and could no longer procure energy, it became a dead, closed system. Fungi and bacteria then played their ecological roles in breaking down the tree. The tree's materials are broken down into their basic parts for other plants to use. This is where fungi find their niches. I hypothesized that the role of Polyporus squamosus is to break down the bark and wood around the perimeter of the stump, while Polyporus pescaprae breaks down the heartwood. Perhaps these two mushrooms, though they live in the same habitat, thrive without competing with each other; each has its own niche in the complex web of life. I found several other pairs of mushrooms that seemed to have this same type of complementary niche relationship.
I then tried to examine more than just the macroscopic physical features of mushrooms. To examine mushrooms at the cellular level, I observed a mushroom specimen of Number 13 under a microscope with 1600x magnification. Using an oil-immersion lens and a crystal violet stain, I obtained exceptional views of gill and cuticle samples. The sample had a lower layer of light brown cells topped by a layer of dark brown spore cells. The only visible organelles were the nuclei in the spore cells and the thick cell wall.
Group #6 Species: LBMs (Little Brown Mushrooms-unidentified)
|Cap||Gills||Annulus/ Ring||Stem/ Stalk||Volva|
|Color||tan/ochre gray at edges light circle in center||brown||none||white, opaque||none|
|Other||2 cm wide||
3 mm wide in diameter|
5 cm tall
- Grows in clusters—confluent stems
- Small, non-fleshy
I also made a spore print of mushroom Number 12 to explore yet another feature of mushrooms. The resulting spore sample looked like a negative image of the mushroom's gills. Fascinated, I would have liked to have made a microscope sketch and a spore sample for each mushroom in my directory.
|These photographs illustrate the mushrooms' progression of decay over a three-week period.|
Before the onset of colder temperatures, I had discovered more than 14 different types of mushrooms in my yard and had documented 12 of them. Using the map of my backyard, I observed that mushrooms grew exclusively in the western half of the yard. This is most likely due to the lower elevation of that portion of the yard, which makes it closer to the water table. In addition, there are many more trees and shrubs on the western side, contributing even more to its shaded and moist environment. Furthermore, the mushrooms that lived under the cover of these trees tended to be hardier and had longer life spans.
In the spring, I hope to continue my expedition and investigate the effects of the seasons on mushroom life. Through the experience of this first expedition, I have learned that humidity and soil temperature readings for each day would have been helpful data to collect. This data could then be used to predict when certain mushrooms are most likely to sprout.
Further understanding of mushrooms could be quite advantageous to humans. We might find new mushrooms that have life-saving medical uses. And each study adds another piece to the ecological puzzle. By being more aware of the world around us, we may take better care of it and better understand our own niche.
The unique physiology of a mushroom continues to amaze me. I was astounded to find so many mushrooms. But why had I found so many when I had never seen a mushroom in my yard before? It's possible that there was a sudden spurt in mushroom activity, but the more likely answer is that I had never taken the time to look carefully. Natural wonders awaiting our discovery teem all around us, even in the tiniest of environments. Discovering them for myself has been a wonderfully fulfilling experience.
"A Peek Into the World of Mushrooms," February 23, 2001. Retrieved from the World Wide Web on October 3, 2002: http://www.allaboutmushrooms.com/mushrooms.htm.
Aurora, David. Mushrooms Demystified. Berkeley: Ten Speed Press, 1986.
Jordan, Peter. Mushroom Identifier. New York: Lorenz Books, 1999.
Laessoe, Thomas, Gary Lincoff, and Anna Del Conte. The Mushroom Book. New York: DK Publishing, 1996.
Lentz, Paul, and John Stevenson. "Mushroom." Microsoft Encarta Online Encyclopedia 2002. Retrieved from the World Wide Web on October 2, 2002: http://encarta.msn.com/encnet/refpages/RefArticle.
Little, Elbert L. Field Guide to Trees, Eastern Region. National Audubon Society. New York: Alfred A. Knopf, Inc., 1980.
McCormick, Bonnie and Christy MacKinnon. Characteristics of Prokaryotic and Eukaryotic Cells. NASA's NOVA Phase III Department of Biology. Retrieved from the World Wide Web on November 2, 2002: http://www.uiwtx.edu:6070/mccormic/mars/activity3.htm.
"Percy Bysshe Shelley."Bartleby.com: Great Books Online. Retrieved from the World Wide Web on October 10, 2002: http://www.bartleby.com/people/ShelleyP.html.
Rinaldi, Augusto, and Vassili Tyndalo. The Complete Book of Mushrooms. New York: Crown Publishers, Inc., 1974.
Wood, Michael. "Fungus Photos." MykoWeb. Retrieved from the World Wide Web on October 3, 2002: http://www.mykoweb.com.
More About This Resource...
This winning entry in the museum's Young Naturalist Awards 2003 examines mushrooms. Yushan's narrative essay, with illustrations and photographs, details:
- how she set out to look for mushrooms in the "advantageous environment" of her backyard
- her surprising discovery of more than 14 different types in this place where she had never before seen a mushroom growing
- her conclusion that "natural wonders awaiting our discovery teem all around us, even in the tiniest of environments"
Less than 1 period.
Supplement a study of biology with an activity drawn from this winning student essay.
- Send students to this online article, or print copies of the essay for them to read.
- Challenge students to go on an expedition in their yards or some other familiar environment, looking for a plant or animal species they've previously overlooked.
- Have the students share their findings with the class.
OriginYoung Naturalist Awards