Activity 2: How the mushroom got its spots


Teachers notes:

This activity is more suitable for KS1 and the lower KS2 years (Ages 5 to 9); however it is a useful tool to illustrate how some mushroom caps develop a spotted appearance and is therefore a useful demonstration to show to ages 10-11 .

See worksheet 11 of ‘How the mushroom got its spots’.

Describe the life cycle of the fungus called the ‘Fly Agaric’ or Amanita muscaria. This fungus helps trees such as pine and birch to grow by capturing water and nutrients from the soil and passing them to the tree. In return the tree gives the Amanita sugars that it has made during photosynthesis. Unfortunately the fruit body or mushroom made by this fungus is poisonous to humans. One of the substances that this fungus produces is called ibotenic acid. This substance is an excellent insecticide and in Victorian times the cap of this fungus was soaked in milk and left to stand on the kitchen shelf. Flies were attracted to the milky insecticidal liquid and were subsequently killed.

The Life Cycle of Amanita muscaria:

The life cycle begins when spores are released from the gills, which are plate like structures under the cap of the mushroom.  When spores land on a surface they begin to grow threads called hyphae.  These threads become longer and branch to form mycelium.  When environmental conditions are just right the mycelium of the fungus forms a tightly

packed knot, which gradually expands to form an immature (baby) mushroom.  When the mushroom is small it is protected by a special coat called the ‘universal veil’.  As it grows in the presence of food and water, the veil breaks and remnants of the veil are left on the top of the mushroom cap.

Here's what to do:

You will need a red balloon, two sheets of tissue paper, a water sprayer bottle and a balloon holder (supplied by most party shops) and a block of plasticine to hold the balloon sticks. Blow up the balloon very slightly to represent a baby mushroom.  Cover it with the tissue paper, holding the tissue paper in place with your thumb and forefinger.  Spray the tissue paper well with water (all living things need water for growth!).  Blow up the balloon which represents the mushroom growing.  The remnants of the veil (broken tissue paper) are left on the top of the cap (the inflated balloon).  That is how the mushroom gets its spots!


Clip the balloon onto a balloon stick and stick it into a block of plasticine until home time.

This is Amanita muscaria the 'Fly Agaric'.  You find its mushroom fruit body under pine and birch trees.  It is an ectomycorrhizal fungus and grows in close association with its host trees, using its underground network of mycelium to capture water and nutrients for tree growth.  In return the tree donates sugars (made during photosynthesis) to its fungal partner.

Demonstrating 'How the mushroom got its spots' at the Cambridge Science Festival 2010

More 'How the mushroom got its spots'

The 'mushroom spots' activity at the BMS 'Fungi Fun' event at the Royal Botanic Garden Edinburgh, October 2010.

Photographs by ama

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