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Jan. 22, 2010

Mushroom Prints

by Austen Saltz

Click to enlarge images
From death caps to puffballs, the fruiting bodies of fungi can be grouped into about a dozen major categories. Mycologist Roy Halling walks us through the wide world of mushrooms and takes us on a fungi foraging foray on the grounds of the New York Botanical Garden in the Bronx.
 
Grade Level: 6th – 8th grade
Subject Matter: Life Science
National Standards: NS.5-8.1, NS.5-8.3
 
 
Overview
Mycology, the study of mushrooms and other fungi, has helped increase our awareness and understanding of fungi and how they affect our daily lives. Fungi play an important role as decomposers, breaking down organic matter and recycling nutrients. Fungi also are responsible for the production of beneficial drugs such as penicillin, and of fermented foods such as breads, wines and cheeses. All over the world, mushrooms also are cultivated for human consumption.
In this lesson, students will be amateur mycologists--collecting and analyzing various mushrooms. Through observation and discussion, students will gain knowledge of the basic anatomy of mushrooms, their life cycle, and their method of reproduction through spores. Students will learn to create spore prints of mushrooms and label and preserve their spore prints, just like a mycologist. Students also will learn that by comparing spore prints, they can identify different mushroom species.
 
Activity Materials
3 - 4 different kinds of whole fresh mushrooms (preferably gill mushrooms)
Sheets of white paper
Glass cups or bowls large enough to cover mushroom caps
Magnifying lenses
Clear hairspray
 
Vocabulary
Fungus – (plural: fungi) an organism from the Fungi kingdom that is separate from animals, plants, or bacteria. Fungi lack chlorophyll to make their food. Instead, they dissolve and absorb their food.
Spore – a small, single cell responsible for reproduction by certain organisms. Spores are extremely resistant to environmental damage and can grow into a new organism.
Hypha – (plural: hyphae) a thread-like tube that forms the body (or mycelium) of a fungus.
Mycelium (plural: mycelia) - the vegetative or non-reproductive part of a fungus made up of a collection of thread-like tubes (or hyphae).
 
What To Do
  1. Start the lesson by having the students watch the video. Ask the students to explain what kind of work a mycologist does. The activity allows students to understand the work of a mycologist.
  2. If possible, take students out on their own fungus foray in a wooded area or local greenmarket where they can pick out different kinds of whole mushrooms--not the packages of sliced mushrooms available in supermarkets. Alternatively, hand out three to four different kinds of whole, fresh mushrooms to each student - including some mushrooms with their mycelia. Ask students to compare and contrast each type of mushroom. N.B.: If mushrooms are picked outdoors, DO NOT eat them! Some mushrooms may be poisonous!
  3. Secure a flat surface where the activity can be left undisturbed, preferably overnight.
  4. One at a time, cut off each mushroom’s stem just below the cap, exposing the circular gill (the thin radiating plates under the mushroom cap). Ask students what they think the gills are for.
  5. Have the students place each cap, gill side down, on a separate piece of white paper. Make sure the students label each sheet with the name of the mushroom and where the mushroom was picked or purchased.
  6. Then have the students carefully cover each of the mushroom caps with the open end of the glass bowl or cup. Leave the covered mushroom caps undisturbed for at least 24 hours. Ask students to predict what will happen to the mushroom caps overnight.
  7. The next day, ask students to observe their mushrooms caps. Are there any obvious changes? Carefully remove the glass covering from each mushroom cap.
  8. Gently lift the mushroom caps from the paper. There should be a radial mushroom spore print under each cap. If a spore print is missing, ask students to think about what variable(s) may have caused the spore print not to appear.
  9. Ask students to observe the spore prints with a magnifying lens and to describe what may have transpired on the sheets of white paper. Compare and contrast the spore prints with each other. Why are some spore patterns different than others? Can these differences help mycologists identify different mushroom species?
  10. After observation, preserve the spore prints by gently spraying each one with clear hairspray. Spray at an angle to avoid blowing the spores away.
What's Happening?
Mushrooms are part of the Fungi kingdom. Mushrooms have two main parts – the fruiting body and the mycelium. When we think of mushrooms, we often think of the soft caps and stems that we see on display in the grocery store or growing from the ground. However, hidden beneath the surface of the soil grows the mycelium. The mycelium grows as it absorbs nutrients from its surroundings. It can grow and live for many years, even after the fruiting body dies. Mushrooms do not have chlorophyll to make their own food. Instead, they feed on dead or decaying organic matter around them.
 
The cap and stem that we commonly eat make up the mushroom’s fruiting body, whose main purpose is to produce microscopic cells called spores. A spore is much like a seed. It contains all of the genetic material that will grow and produce the fruit of the mushroom. In order to grow, a spore needs to land in a suitable environment (a warm, moist and shaded area). When a spore lands on an ideal setting, it sends out thread-like filaments called hyphae. Underground, these hyphae move outward and produce the web-like mycelium. A stalk and cap will grow above ground from the mycelium. Mycologists use spore size, shape and color to help identify an unknown species of mushroom.
 
Topics for Science Class Discussion
  • How does the Fungi kingdom differ from other kingdoms?
  • How does spore reproduction differ from seed reproduction? How are they similar?
  • Why are fungi a vital part of our ecosystem?
  • How many species of mushrooms have been documented? What is the estimated percentage of undocumented species?
Extended Activities and Links
  • Measure and compare the diameter, radius and circumference of various mushroom caps.
  • Dissect and label parts of a mushroom.
  • Grow your own mushrooms at home or in school. Create a slideshow of the life cycle of your mushroom by taking pictures during various stages of its growth. Mushroom growing kits are available for $18 - $25 at:
  • Create a chart of other types of fungi and label them as friends (positive impact) or foes (negative impact). Are there some fungi that are both?
  • Experiment with yeast, another form of fungi found in many households, and observe the build up of carbon dioxide released from activated yeast.

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About Austen Saltz

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